 |
 | Home | Contact Us | FAQ | Search & Site Map | Link to Us |
 | Sign In | Join | Other 45 Sites in Network |
| PhotoKB HomeDiscussion Groups Digital Photography Digital PhotoDSLR CamerasZLR CamerasPoint & Shoot CamerasFilm Photography 35 mmLarge FormatMedium formatDarkroomFilm and LabsOther EquipmentPhoto Technique Nature PhotographyPeople PhotographyTechnique GeneralGeneral Photo Topics General TopicsAustralian PhotographyUK PhotographyDirectoryPhoto Clubs |
Photo Forum / Digital Photography / DSLR Cameras / March 2005Nikkor 12-24 vs. Canon 10-22
Finally I am going to switch from film totally. I am to either go Canon or Nikon and totally based on this WA question. I will do 85% of my work with the WA lens. My work is crime scenes. Mostly alleys and interiors ... some at night. I prefer not using flash and rather use a tripod when necessary. Which lens is better with regards to sharpness and lack of distortion? Not having a big budget, it is going to be D70 or Rebel XT based solely on this lens choice. Thank you all for any input. Marty > Finally I am going to switch from film totally. I am to either go > Canon or Nikon and totally based on this WA question. I will do 85% of [quoted text clipped - 9 lines] > > Marty I don't now whether you do this 'officially' for police or legal reasons, but if you will be in a position to rely on your shots as evidence in a court, you may be called on to prove the authenticity of your pictures. A negative is generally regarded as incontrovertible proof of authenticity, but the ease with which digital images can be tampered with generally means it is harder to prove the image as genuine. Canon is working on (may have it on the market now, as I haven't been following the progress) a system that will be proof of authenticity for a digital image, for the reasons outlined above. I am unaware of any move in that direction by Nikon, or any other maker of digital cameras. This may well dictate your choice of camera, and hence lens. Colin >> Finally I am going to switch from film totally. I am to either go >> Canon or Nikon and totally based on this WA question. I will do 85% of [quoted text clipped - 26 lines] > >Colin Thank you. I do use the stuff in homicide defense cases ... mostly death penalty. I have been doing this for about forty years as a cop first and defense after that. (I am pretty old.) The standard here in Maryland is that the picture fairly and accurately represents the scene as it was observed by the photographer. I have never been asked for a negative ... yet. Nor have I been asked if the photos were made using film or digital. I have, during the past two years, used some digital p&s without question so far. Thanks again for your input. FWIW: Canon's "data verification kit" has been available for quite a while. I've seen a web page on it, and a magazine (web) article on it, but I just went to the Canon USA web site ... and their search capabilities are soo anemic that you will have a hard time finding it. The "official" name is "Canon Data Verification Kit DVK-E2." http://www.dpreview.com/news/0401/04012903canondvke2.asp http://www.adorama.com/ICADVKE1.html http://www.bhphotovideo.com/product/266214/CADVKE1/REG/4969 http://www.canoncompanystore.com/epages/annex.storefront > >> Finally I am going to switch from film totally. I am to either go > >> Canon or Nikon and totally based on this WA question. I will do 85% of [quoted text clipped - 37 lines] > > Thanks again for your input. > FWIW: > Canon's "data verification kit" has been available for quite a while. I've > seen a web page on it, and a magazine (web) article on it, but I just went > to the Canon USA web site ... and their search capabilities are soo anemic > that you will have a hard time finding it. The "official" name is "Canon > Data Verification Kit DVK-E2." Based on what Marty and McLeod (the working pros in this area) have both indicated, this would appear to be another solution for a problem that doesn't exist. Walt > Based on what Marty and McLeod (the working pros in this area) have both > indicated, this would appear to be another solution for a problem that > doesn't exist. Legal systems move slowly (as they should). Society is still figuring out how seriously to take cryptographic evidence. Perhaps it will take an unusual case to establish the admissibility of this kind of cryptographic evidence. Like one where the facts are hotly contested and the photographer is dead or otherwise unavailable. I'm not holding my breath. But it's a cool idea and I do think it deserves and will some day see its day in the sun.  SignatureBen Rosengart (212) 741-4400 x215 Sometimes it only makes sense to focus our attention on those questions that are equal parts trivial and intriguing. --Josh Micah Marshall > Based on what Marty and McLeod (the working pros in this area) have both > indicated, this would appear to be another solution for a problem that > doesn't exist. > > Walt It might exist someday. Wait until some circumstance arises where a defense lawyer has an opportunity to call the photo into question. >> Based on what Marty and McLeod (the working pros in this area) have both >> indicated, this would appear to be another solution for a problem that [quoted text clipped - 4 lines] > It might exist someday. Wait until some circumstance arises where a > defense lawyer has an opportunity to call the photo into question It would take an incredibly big case and clear alteration of evidence to get long-standing legal precedent set aside. Walt >>>Based on what Marty and McLeod (the working pros in this area) have both >>>indicated, this would appear to be another solution for a problem that [quoted text clipped - 9 lines] > > Walt Well, it can still happen despite how slim the chances might be. The lawyers should start to get ready to prove their photographic evidents. > > It might exist someday. Wait until some circumstance arises where a > > defense lawyer has an opportunity to call the photo into question > > It would take an incredibly big case and clear alteration of evidence to get > long-standing legal precedent set aside. I'm sure of it. But things have a funny way of coming about. What if a journalist snapped photos of a crime in progress with a digital camera and those photos were used as evidence, much as closed- circuit video footage is? Would someone dare accuse the photographer of digital manipulation, and would the judge be stupid enough to believe him? >> > It might exist someday. Wait until some circumstance arises where a >> > defense lawyer has an opportunity to call the photo into question [quoted text clipped - 10 lines] > digital manipulation, and would the judge be stupid enough to believe > him? Accuse - certainly. And if the images were the only evidence the prosecution had, the accusation might carry some weight. But the images are never the only evidence. This issue has to be considered within the global context of what occurs in a trial. And if it ever happens that a conviction is lost because of it, then the technology will be needed. But by then, everything discussed here today will be technologically "old news." Walt > > circuit video footage is? Would someone dare accuse the photographer of > > digital manipulation, and would the judge be stupid enough to believe [quoted text clipped - 4 lines] > never the only evidence. This issue has to be considered within the global > context of what occurs in a trial. You're correct in the fact the prosecution could never go to trial with photos alone - but they could go to trial with their case heavily dependant on photographs of the crime in progress. > And if it ever happens that a conviction is lost because of it, then the > technology will be needed. But by then, everything discussed here today > will be technologically "old news." > > Walt Well, a conviction was lost because a glove "didn't fit". Well, that, really lousy police work and a star-struck judge. Canon seems to be thinking a little too far ahead on this issue. To my knowledge, no one is using/has bought those data verification kits. The one market they may of had, crime scene/police photographers, apparently doesn't need them! 2005-03-09, Brian C Baird wrote: >[...] > Canon seems to be thinking a little too far ahead on this issue. To my > knowledge, no one is using/has bought those data verification kits. The > one market they may of had, crime scene/police photographers, apparently > doesn't need them! I find that hard to believe. Even outside crime scene/police work the need to be able to ,,sign'' digital documents (be it photo's or something else) is obvious, and people have been doing it for a long time (way before 1999 so how this patent came about someone mentioned in another posting...). Well, if it is true, it is time to get worried about the police force... -peter > I find that hard to believe. Even outside crime scene/police work the need > to be able to ,,sign'' digital documents (be it photo's or something else) > is obvious, and people have been doing it for a long time (way before 1999 > so how this patent came about someone mentioned in another posting...). The patent isn't on signing data, it's on a camera that signs its output. This is cool because as long as the camera is relatively tamperproof, the photographer need not be trusted! (You can see why spying and insurance came to mind as target markets.) SignatureBen Rosengart (212) 741-4400 x215 Sometimes it only makes sense to focus our attention on those questions that are equal parts trivial and intriguing. --Josh Micah Marshall >> I find that hard to believe. Even outside crime scene/police work the need >> to be able to ,,sign'' digital documents (be it photo's or something else) [quoted text clipped - 5 lines] >tamperproof, the photographer need not be trusted! (You can see >why spying and insurance came to mind as target markets.) I don't want to know how you can patent something a trivial as that. (If the camera has to sign it, there is a trivial way around it, just have to camera encrypt the data and have some other device decrypt and sign the data. Using public keys this is relatively easy to secure, doesn't require anything special in the camera (other than a public key) and provides confidentiality when images are transmitted wireless.). SignatureThat was it. Done. The faulty Monk was turned out into the desert where it could believe what it liked, including the idea that it bad been done by. It was allowed to keep its horse, since horses where so cheap to make. -- Douglas Adams in Dirk Gently's Holistic Detective Agency >>The patent isn't on signing data, it's on a camera that signs its >>output. This is cool because as long as the camera is relatively >>tamperproof, the photographer need not be trusted! (You can see >>why spying and insurance came to mind as target markets.) > > I don't want to know how you can patent something a trivial as that. It fits all the criteria of a patentable concept. Lots of things are "trivial" once someone else has thought of it and told you about it. > (If the camera has to sign it, there is a trivial way around it, just > have to camera encrypt the data and have some other device decrypt and > sign the data. Using public keys this is relatively easy to secure, doesn't > require anything special in the camera (other than a public key) and > provides confidentiality when images are transmitted wireless.). No. (I guess it's not so "trivial" after all.) SignatureBen Rosengart (212) 741-4400 x215 Sometimes it only makes sense to focus our attention on those questions that are equal parts trivial and intriguing. --Josh Micah Marshall >> I don't want to know how you can patent something a trivial as that. > >It fits all the criteria of a patentable concept. > >Lots of things are "trivial" once someone else has thought of it and >told you about it. Get real. >> (If the camera has to sign it, there is a trivial way around it, just >> have to camera encrypt the data and have some other device decrypt and [quoted text clipped - 3 lines] > >No. (I guess it's not so "trivial" after all.) What no? The signature box generates for each camera a public/private key pair. The public key is transfered to the camera. (How you transfer the public key depends on who you trust, it is possible that the camera needs a private key of its own to allow the key to be installed in a secure way). For each image the camera generates a random key for a shared key system and encrypts the image. The camera encrypts the shared key with the public key of the signature box. The signature box is the only thing that can decrypt the image. After decryption, the box signs the image. Be my guest, how do you break this scheme... SignatureThat was it. Done. The faulty Monk was turned out into the desert where it could believe what it liked, including the idea that it bad been done by. It was allowed to keep its horse, since horses where so cheap to make. -- Douglas Adams in Dirk Gently's Holistic Detective Agency > What no? The signature box generates for each camera a public/private key > pair. The public key is transfered to the camera. (How you transfer the [quoted text clipped - 4 lines] > and encrypts the image. The camera encrypts the shared key with the > public key of the signature box. There is nothing here to prevent impersonation of the camera. Perhaps you didn't understand the point of the exercise? SignatureBen Rosengart (212) 741-4400 x215 Sometimes it only makes sense to focus our attention on those questions that are equal parts trivial and intriguing. --Josh Micah Marshall >> What no? The signature box generates for each camera a public/private key >> pair. The public key is transfered to the camera. (How you transfer the [quoted text clipped - 7 lines] >There is nothing here to prevent impersonation of the camera. >Perhaps you didn't understand the point of the exercise? There is because the 'public key' is not public. (That's why I included the text about installing the key in a secure way and having a per camera public/private key pair). Of course the signature box can impersonate the camera. But that should be no problem. SignatureThat was it. Done. The faulty Monk was turned out into the desert where it could believe what it liked, including the idea that it bad been done by. It was allowed to keep its horse, since horses where so cheap to make. -- Douglas Adams in Dirk Gently's Holistic Detective Agency > There is because the 'public key' is not public. I am committed to being friendly and polite in this newsgroup. So I am not going to discuss cryptography with you any more. SignatureBen Rosengart (212) 741-4400 x215 Sometimes it only makes sense to focus our attention on those questions that are equal parts trivial and intriguing. --Josh Micah Marshall > (If the camera has to sign it, there is a trivial way around it, just > have to camera encrypt the data and have some other device decrypt and > sign the data. Using public keys this is relatively easy to secure, doesn't > require anything special in the camera (other than a public key) and > provides confidentiality when images are transmitted wireless.). I'm not sure why it has to be that involved. Each individual camera could have a key associated with its serial number. Sign the image with the private key and anyone can D/L the public key (from the OEM website) and verify it. Cheers, Alan Signature-- r.p.e.35mm user resource: http://www.aliasimages.com/rpe35mmur.htm -- r.p.d.slr-systems: http://www.aliasimages.com/rpdslrsysur.htm -- [SI] gallery & rulz: http://www.pbase.com/shootin -- e-meil: there's no such thing as a FreeLunch. >> (If the camera has to sign it, there is a trivial way around it, just >> have to camera encrypt the data and have some other device decrypt and [quoted text clipped - 6 lines] >the private key and anyone can D/L the public key (from the OEM website) >and verify it. The assumption is that what you just wrote was non-obvious in 1999 and a patent was granted. So, if you want to work around the concept of having the camera sign the image, you have to have some other device do the actual signing. SignatureThat was it. Done. The faulty Monk was turned out into the desert where it could believe what it liked, including the idea that it bad been done by. It was allowed to keep its horse, since horses where so cheap to make. -- Douglas Adams in Dirk Gently's Holistic Detective Agency > The assumption is that what you just wrote was non-obvious in 1999 > and a patent was granted. > > So, if you want to work around the concept of having the camera sign > the image, you have to have some other device do the actual signing. I see. If this feature is actually required, a new body can be issued with the appropriate s/w. Cheers, Alan Signature-- r.p.e.35mm user resource: http://www.aliasimages.com/rpe35mmur.htm -- r.p.d.slr-systems: http://www.aliasimages.com/rpdslrsysur.htm -- [SI] gallery & rulz: http://www.pbase.com/shootin -- e-meil: there's no such thing as a FreeLunch. >>> (If the camera has to sign it, there is a trivial way around it, just >>> have to camera encrypt the data and have some other device decrypt and [quoted text clipped - 9 lines] > The assumption is that what you just wrote was non-obvious in 1999 and a > patent was granted. I disagree, it was obvious even then. The whole mechanism of signing and public/private key cryptography was well known: putting it in a camera should IMHO not be patentable. -peter >>>I'm not sure why it has to be that involved. Each individual camera >>>could have a key associated with its serial number. Sign the image with [quoted text clipped - 7 lines] >public/private key cryptography was well known: putting it in a camera >should IMHO not be patentable. I agree with that. SignatureThat was it. Done. The faulty Monk was turned out into the desert where it could believe what it liked, including the idea that it bad been done by. It was allowed to keep its horse, since horses where so cheap to make. -- Douglas Adams in Dirk Gently's Holistic Detective Agency > I disagree, it was obvious even then. The whole mechanism of signing and > public/private key cryptography was well known: putting it in a camera > should IMHO not be patentable. Nothing that is software should be patentable. Software patents are evil. SignatureJeremy | jeremy@exit109.com >> I disagree, it was obvious even then. The whole mechanism of signing and >> public/private key cryptography was well known: putting it in a camera >> should IMHO not be patentable. > > Nothing that is software should be patentable. Software patents are evil. Agreed. The technology in question is a marriage of software and hardware, so it's not as clear-cut as all that. SignatureBen Rosengart (212) 741-4400 x215 Sometimes it only makes sense to focus our attention on those questions that are equal parts trivial and intriguing. --Josh Micah Marshall >> Nothing that is software should be patentable. Software patents are evil. > > Agreed. The technology in question is a marriage of software and > hardware, so it's not as clear-cut as all that. But it's not an invented device, it's just a way of using something that already exists. It's no more a marriage of software and hardware than any other software is, by virtue of running on a hardware computer. SignatureJeremy | jeremy@exit109.com > But it's not an invented device, it's just a way of using something that > already exists. It's no more a marriage of software and hardware than > any other software is, by virtue of running on a hardware computer. I don't agree. It's a system that happens to include a software component. But I think there's room for reasonable people to disagree on this. SignatureBen Rosengart (212) 741-4400 x215 Sometimes it only makes sense to focus our attention on those questions that are equal parts trivial and intriguing. --Josh Micah Marshall >> But it's not an invented device, it's just a way of using something that >> already exists. It's no more a marriage of software and hardware than [quoted text clipped - 3 lines] >component. But I think there's room for reasonable people to >disagree on this. Given the existance of a digital camera with downloadable firmware, adding a digital signature function is just software. The reason a camera is not a general purpose computer is not due to hardware limitations, but due to the fact that the hardware details are not published. The fact that there is both hardware and software is commonly used in Europe to circumvent the part of the patent law that prohibits software patents. The only extra hardware you need for security in an untrusted environment is some amount of temper resistant storage (and other hardware protection). But that is generic and not new. Secure digital co-processors were invented well before 1999. I doubt that Canon cameras are actually temper resistant. They probably assume that nobody is going to reverse enigneer them. SignatureThat was it. Done. The faulty Monk was turned out into the desert where it could believe what it liked, including the idea that it bad been done by. It was allowed to keep its horse, since horses where so cheap to make. -- Douglas Adams in Dirk Gently's Holistic Detective Agency > I doubt that Canon cameras are actually temper resistant. I doubt that as well. If we're right, then that's the single biggest difference between their implementation and the proposal I worked on. BTW, in addition to secure storage, I figured you'd want a way to keep an attacker from impersonating the sensor. I figure by simply protecting the connection between the sensor and the rest of the system. SignatureBen Rosengart (212) 741-4400 x215 Sometimes it only makes sense to focus our attention on those questions that are equal parts trivial and intriguing. --Josh Micah Marshall >> But it's not an invented device, it's just a way of using something that >> already exists. It's no more a marriage of software and hardware than [quoted text clipped - 3 lines] > component. But I think there's room for reasonable people to > disagree on this. Sorry. I see no "invention" here whatsoever, unless there is some new and previously-nonexisting component in the camera somewhere that wasn't mentioned. If you're talking about a "method" or "process", I consider patents on those to be the same as software patents -- completely indefensible. SignatureJeremy | jeremy@exit109.com > >> I find that hard to believe. Even outside crime scene/police work the need > >> to be able to ,,sign'' digital documents (be it photo's or something else) [quoted text clipped - 7 lines] > > I don't want to know how you can patent something a trivial as that. Have you seen the patents that have made it through the system in the last 15 years? Greg > Have you seen the patents that have made it through the system in the last > 15 years? I particularly like 5443036. The patent system is completely broken. SignatureJeremy | jeremy@exit109.com > Accuse - certainly. And if the images were the only evidence the > prosecution had, the accusation might carry some weight. But the images are > never the only evidence. This issue has to be considered within the global > context of what occurs in a trial. You are without a clue. If someone submits evidence that is later shown to be a forgery or similar on the part of the submitter, it casts a major pall on the rest of the case. So severe a dread, that the likelihood of dismissal, mis-trial or at least suppression of other evidence (and the concommitant loss of a prosecution/defense) is very high, if not an absolute certainty. Indeed, it can effect other, unrelated, cases. This isn't idle speculation: it has happened. www.google.com: rampart los angeles police www.google.com: toronto drug squad scandal www.google.com: FBI lab scandal etc etc etc It strikes me that anything that can preclude abuse to a very high degree of probability, is fairly easy to implement, at almost no user cost, is a Very Good Thing and to be Highly Desired. > And if it ever happens that a conviction is lost because of it, then the > technology will be needed. A character of intelligence is to foresee predictable consequences of one's actions. Only an idiot would build a house on a river flood plain, asserting that "if the house is lost only then the technology for a better house construction or location be needed". Why adopt a "new" form of evidence that is open to trivial abuse? Why accept the mere word of the photographer that the image is a "faithful" rendition of the scene, when, in addition, there could be a proof-process that stretches from the court room, though whatever information processing systems, all the way back to who was touching the camera at the time the shutter was tripped? (c.f. chain of evidence rules.) Basically, why lay the groundwork for a future scandal? >Why adopt a "new" form of evidence that is open to trivial abuse? Why, indeed? Fortunately, no such new form of evidence is being proposed > Why accept the mere word of the photographer that the image is > a "faithful" rendition of the scene . . . Because, basically, that is the primary form of evidence that the courts require. Technology is all very well, but with the exeption of a few special cases (speed cameras, for example) evidence must be presented and sworn to by a human being. There are two important principles here; somebody affirming under oath that the evidence is true, and that same person being present, in court, to be cross-examined. > There are two important principles here; somebody affirming > under oath that the evidence is true, and that same person > being present, in court, to be cross-examined. What good is the affirmation if in fact the image was modified along the way to court? Even subtle changes can be highly signifigant. This is what a "digital chain of evidence" would establish: in addition to the guy who took the picture, we can now call the guy who processed the image, the guy who printed it, the guy who drove the courier truck, or whatever. Basically, if necessary, the proveance of the bits before the court could be completely established right back to the analog to digital converter, exactly analogous to physical evidence. Interestingly, the recent case of USA v. Ahmed Abdel Sattar, Lynne Stewart and Mohammed Yousry (see http://www.lynnestewart.org/transcripts.html) had some difficulties in this area. Some of the audio intercepts used as evidence in the case were only in digital form as the original tapes were missing, destroyed, gone or otherwise unusable. Various transformations were done on these files, from computer to computer and software system to system. The defence team tried to make the obvious point, but (if I recall -- it's been a while since I read the transcripts), the evidence was allowed in anyways more or less because the judge simply believed the government or whomever they called make the affirmation to "trust us, everything is ok". > What good is the affirmation if in fact the image was modified along I suggest you move this thread to a law forum. Signature-- r.p.e.35mm user resource: http://www.aliasimages.com/rpe35mmur.htm -- r.p.d.slr-systems: http://www.aliasimages.com/rpdslrsysur.htm -- [SI] gallery & rulz: http://www.pbase.com/shootin -- e-meil: there's no such thing as a FreeLunch. > Canon is working on (may have it on the market now, as I haven't been > following the progress) a system that will be proof of authenticity for > a digital image, for the reasons outlined above. It's out there; in its second version, even. The part is the DVK-E2. The press release says it works with the 1Ds and the 1D MkII. I'd guess it works with the 1Ds MkII as well. Somewhere on dpreview, it says that this thing works with the 20D, but I have a 20D and I don't believe that that's correct. http://www.dpreview.com/news/0401/04012903canondvke2.asp I was awfully chagrined when the DVK-E2's release was covered on Slashdot about a year ago, as I had been working for several months on a nearly identical invention. Canon and I even identified the same target markets: news, law enforcement, insurance, and spies -- though they didn't mention spies in their press release. :-) The patent, it turns out, dates from 1999 or thereabouts. So I wasn't even close. SignatureBen Rosengart (212) 741-4400 x215 Sometimes it only makes sense to focus our attention on those questions that are equal parts trivial and intriguing. --Josh Micah Marshall Op Tue, 8 Mar 2005 15:43:20 +0000 (UTC) schreef Ben Rosengart <br+rpdss@panix.com>: >t's out there; in its second version, even. The part is the DVK-E2. >The press release says it works with the 1Ds and the 1D MkII. I'd >guess it works with the 1Ds MkII as well. Somewhere on dpreview, it >says that this thing works with the 20D, but I have a 20D and I >don't believe that that's correct. From the website of B&H: The Canon EOS-1Ds Mark II and EOS 20D digital cameras can prove it's images are unaltered, original files. The Data Verification Kit DVK-E2, consisting of a dedicated memory card, a Secure Mobile (SM) card reader, and special software for Windows 2000/XP is able to verify that EOS-1Ds Mark II and EOS 20D image files are absolutely unaltered. The system is so precise, that even the slightest discrepancy is detected. This may well be a landmark for digital imaging in law enforcement and other documentary uses. When the EOS-1Ds Mark II and EOS 20D user shoots with the verification system activated (P.Fn-31), a code is automatically generated based on the image contents and attached to the image. When the image is viewed, the data verification software determines the code for the image and compares it with the attached code. If the photo has been retouched in any way, the codes will not match, thus verifying that the image is not the original. you can send email to me using mendelson-at-mendelson-dot-nl www.mendelson.nl > From the website of B&H: > [...] > > When the EOS-1Ds Mark II and EOS 20D user shoots with the verification > system activated (P.Fn-31), The 20D doesn't have "personal functions", it has "custom functions", and they only go up to 18. I've looked at all of them and none is for data verification. SignatureBen Rosengart (212) 741-4400 x215 Sometimes it only makes sense to focus our attention on those questions that are equal parts trivial and intriguing. --Josh Micah Marshall Op Tue, 8 Mar 2005 16:01:43 +0000 (UTC) schreef Ben Rosengart <br+rpdss@panix.com>: >> From the website of B&H: >> [...] [quoted text clipped - 5 lines] >and they only go up to 18. I've looked at all of them and none is >for data verification. Then the B&H website must be wrong. And so is amazon: http://www.amazon.com/exec/obidos/tg/detail/-/B0002XQJFA/002-6192499-9763241?v=glance. >Additional Accessories In addition to Canon's EF series of lenses and Speedlites, several other accessories are designed to work specifically with the EOS 20D. The Battery Grip BG-E2 adds a vertical shutter release, and is compatible with up to two of Canon's BP-511/511A/512/514 lithium-ion battery packs, or alternatively a set of six AA batteries, for greater convenience when traveling. Canon's Semi Hard Case EH/7-L can accommodate the EOS 20D with a small zoom lens (EF-S17-85mm f4-5.6 IS USM included), and the EOS 20D is compatible with Canon's DVK-E2 image data verification kit to check original image data authenticity, whenever verification is essential. and http://www.dpreview.com/news/0408/04081909canon_eos20d.asp and http://www.canon.ru/products/about.asp?id=1298 ?????? EOS 20D ?????????? ? ????????????? ????????????? ?????????? ??? ???????? ?????? DVK-E2, ??????? ??????????? ? ?????? ????????? ????????, ? ??????? ? ? ??????????? ?????? ??? ???????? ??????????? ?????? ???? ??????? ???????????. and: http://www.canon.lt/products/about.asp?id=1298 and http://www.canon.co.uk/about_us/news/consumer_releases/eos20d.asp and: http://www.canon.com.ph/inpage.asp?mainContent=327 and: http://consumer.usa.canon.com/ir/controller?act=SNAModelSuppliesAct&fcategoryid= 816&modelid=10464 and finally from canon USA: Data Verification Kit DVK-E2 9314A001AA In Stock Price: $1,100.00 Like its predecessor, this kit can verify whether or not a photo is an untouched original. But its use of a Secure Mobile (SM) card reader, instead of an IC card reader, makes it more compact than the previous version. Moreover, the versatile DVK-E2 is able to verify images photographed by the EOS-1Ds as long as they are appended with a data verification image. Includes card reader, IC card, Software CD. Models: EOS 1D Mark II, EOS 20D, EOS 1DS end of list and quotes. But how it works? I don't know, i don't own a 20D yet. Bart you can send email to me using mendelson-at-mendelson-dot-nl www.mendelson.nl > Op Tue, 8 Mar 2005 16:01:43 +0000 (UTC) schreef Ben Rosengart ><br+rpdss@panix.com>: [quoted text clipped - 5 lines] > Then the B&H website must be wrong. And so is amazon: > [...] Five bazillion vendors plus Canon themselves can't be wrong, eh? I just checked the manual. The hitherto-mysterious Custom Function 18, "Add original decision data," is indeed for use with the DVK-E2. Sorry for spreading misinformation, and thanks for setting me straight! SignatureBen Rosengart (212) 741-4400 x215 Sometimes it only makes sense to focus our attention on those questions that are equal parts trivial and intriguing. --Josh Micah Marshall Op Tue, 8 Mar 2005 16:47:08 +0000 (UTC) schreef Ben Rosengart <br+rpdss@panix.com>: >> Op Tue, 8 Mar 2005 16:01:43 +0000 (UTC) schreef Ben Rosengart >><br+rpdss@panix.com>: [quoted text clipped - 7 lines] > >Five bazillion vendors plus Canon themselves can't be wrong, eh? Not only vendors but also the always correct Canon Lituania :-) ! you can send email to me using mendelson-at-mendelson-dot-nl www.mendelson.nl >From the website of B&H: > [quoted text clipped - 6 lines] >discrepancy is detected. This may well be a landmark for digital >imaging in law enforcement and other documentary uses. In the crypto world this is usually called a digital signature. The easiest way to do this is give each camera a small piece of temperistant storage (for the key), and a certificate for the key. (And updated firmware to compute signatures). No need for a dedicated memory card, or a secure card reader. The tricky part is of course to make sure that the key is well protected. (Given the decicated memory card and the secure card reader, it is possible that the actual digital signature is computed in the secure card reader, and that before that a less secure scheme is used. A MAC between the camera and the secure card reader is also possible, but that does not require a dedicated card. The deciated card suggests that the card recognizes the camera, that camera does not do anything special, and that the secure card reader recognizes the card and computes the signature.) SignatureThat was it. Done. The faulty Monk was turned out into the desert where it could believe what it liked, including the idea that it bad been done by. It was allowed to keep its horse, since horses where so cheap to make. -- Douglas Adams in Dirk Gently's Holistic Detective Agency >>From the website of B&H: >> [quoted text clipped - 16 lines] > >The tricky part is of course to make sure that the key is well protected. It would be simple enough to use a MD5 hash of a combination of the image and the camera's model number and serial number -- plus a private key hidden in the camera. This should suffice for a signature. (Hmm ... toss in the date too -- so that can be verified as well -- compare the date stored in the image's info fields with that rolled into the MD5 hash, so a photo taken later could not be substituted.) >(Given the decicated memory card and the secure card reader, it is possible >that the actual digital signature is computed in the secure card reader, [quoted text clipped - 4 lines] >and that the secure card reader recognizes the card and computes the >signature.) The card could contain its own serial number, too. I presume that such are available on flash cards. They are certainly encoded in modern SCSI drives, and can be read by the system. Of course, something like PGP (or some other private-key/public-key cipher) would be better (more secure), but that would require more processing power in the camera -- perhaps taking the frame rate down to something like one frame per minute. :-) O.K. On a 300 MHz Ultra-SPARC CPU, a md5 hash of a 1.5 MB JPEG image takes: 0.06u 0.04s 0:00.17 58.8% that is -- 60 mS of user time, 40 mS of system time, or 0.17 seconds of wall clock time, with the CPU having 58.8% of the system's resources at the time. A similarly fast and capable CPU in the camera would take something closer to the sum of the first two -- or 100 mS (0.1 seconds). A PGP signature would take somewhat longer, and a full PGP encryption of the entire file would take significantly longer -- so it depends on how much security you need -- and how much you are willing to accept that the encrypted image may become unrecoverable from a single bit error near the beginning. :-) I think that the PGP signature would be the best, with a private key in the camera (or the flash card), and a public key in the reader for verification. That way, it would not matter whether the reader was destroyed, as long as a record of the public key was available. And -- there is no real reason to keep the public key secret, so *anyone* could verify a copy of the image. Enjoy, DoN. SignatureEmail: <dnichols@d-and-d.com> | Voice (all times): (703) 938-4564 (too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html --- Black Holes are where God is dividing by zero --- > It would be simple enough to use a MD5 hash of a combination of > the image and the camera's model number and serial number -- plus a > private key hidden in the camera. This should suffice for a signature. > (Hmm ... toss in the date too -- so that can be verified as well -- > compare the date stored in the image's info fields with that rolled into > the MD5 hash, so a photo taken later could not be substituted.) Make it SHA-256, in light of the recently discovered flaws in MD5 and SHA-1. And how about tossing in GPS info as well? :-) > Of course, something like PGP (or some other > private-key/public-key cipher) would be better (more secure), but that > would require more processing power in the camera -- perhaps taking the > frame rate down to something like one frame per minute. :-) You weren't speaking of a public-key system when you referred to a "private key"? > O.K. On a 300 MHz Ultra-SPARC CPU, a md5 hash of a 1.5 MB JPEG > image takes: I think the expensive part is the public-key math -- which is still not so bad since you're only signing a hash, not the message itself. (Ok, I'm handwaving here, I'm not actually sure which is more costly.) > A PGP signature would take somewhat longer, and a full PGP > encryption of the entire file would take significantly longer There's also no real reason to do that. > -- so it > depends on how much security you need -- and how much you are willing to > accept that the encrypted image may become unrecoverable from a single > bit error near the beginning. :-) I think that the PGP signature would > be the best, with a private key in the camera (or the flash card), and a > public key in the reader for verification. Agreed, though it could just as easily be x.509. As my friend Thor pointed out to me when I was working on this, you can include the camera public key in the signed image, if you sign it with the vendor's private key. Then there's only one public key that everyone needs: the vendor's. I have some very nice diagrams of all of this that I commissioned when I still thought I was going to apply for a patent. :-) Talk about your expensive mistakes. SignatureBen Rosengart (212) 741-4400 x215 Sometimes it only makes sense to focus our attention on those questions that are equal parts trivial and intriguing. --Josh Micah Marshall >> It would be simple enough to use a MD5 hash of a combination of >> the image and the camera's model number and serial number -- plus a [quoted text clipped - 5 lines] >Make it SHA-256, in light of the recently discovered flaws in MD5 >and SHA-1. O.K. I wasn't following that. > And how about tossing in GPS info as well? Probably not a bad idea, if the camera is equipped to record GPS info into the image (something which would be useful in some fields -- including your spies. :-) >> Of course, something like PGP (or some other >> private-key/public-key cipher) would be better (more secure), but that [quoted text clipped - 3 lines] >You weren't speaking of a public-key system when you referred to a >"private key"? Not in the first instance -- just as something unique to the camera, and not predictable from the camera's serial number and model number. Maybe a hash of the owner's birthdate, plus other bits of information, or anything else, as long as it is not a known relationship to anyone else. Or even better -- a digitization of his/her right big toe (finger?)print. :-) >> O.K. On a 300 MHz Ultra-SPARC CPU, a md5 hash of a 1.5 MB JPEG >> image takes: > >I think the expensive part is the public-key math -- which is still >not so bad since you're only signing a hash, not the message itself. >(Ok, I'm handwaving here, I'm not actually sure which is more costly.) Actually -- the most expensive, I believe, is the generation of the initial public-key/private-key pair -- at least based on the initialization of PGP. >> A PGP signature would take somewhat longer, and a full PGP >> encryption of the entire file would take significantly longer > >There's also no real reason to do that. Agreed. Anyone should be able to examine the image, and to use it without needing to decrypt it. (Though your spy might like the encrypted version. :-) >> -- so it >> depends on how much security you need -- and how much you are willing to [quoted text clipped - 4 lines] > >Agreed, though it could just as easily be x.509. O.K. I was mentioning PGP as the one most easy to come by, and most familiar to me. (That and GPG.) >As my friend Thor pointed out to me when I was working on this, >you can include the camera public key in the signed image, if you >sign it with the vendor's private key. Then there's only one public >key that everyone needs: the vendor's. O.K. If the public key is in the encrypted signature, and not in the unencrypted info. >I have some very nice diagrams of all of this that I commissioned >when I still thought I was going to apply for a patent. :-) Talk >about your expensive mistakes. Sorry about that. Better luck with your next project. Enjoy, DoN. SignatureEmail: <dnichols@d-and-d.com> | Voice (all times): (703) 938-4564 (too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html --- Black Holes are where God is dividing by zero --- > Actually -- the most expensive, I believe, is the generation of > the initial public-key/private-key pair -- at least based on the > initialization of PGP. Fortunately that doesn't have to be done in the camera. >>As my friend Thor pointed out to me when I was working on this, >>you can include the camera public key in the signed image, if you [quoted text clipped - 3 lines] > O.K. If the public key is in the encrypted signature, and not > in the unencrypted info. No reason for the public key to be encrypted. It's public. It just needs to be signed. >>I have some very nice diagrams of all of this that I commissioned >>when I still thought I was going to apply for a patent. :-) Talk >>about your expensive mistakes. > > Sorry about that. Better luck with your next project. Thanks. I can't really complain: I had fun, and maybe some day I'll get to use what I learned about the patent system. SignatureBen Rosengart (212) 741-4400 x215 Sometimes it only makes sense to focus our attention on those questions that are equal parts trivial and intriguing. --Josh Micah Marshall >> Actually -- the most expensive, I believe, is the generation of >> the initial public-key/private-key pair -- at least based on the >> initialization of PGP. > >Fortunately that doesn't have to be done in the camera. Amen! >>>As my friend Thor pointed out to me when I was working on this, >>>you can include the camera public key in the signed image, if you [quoted text clipped - 6 lines] >No reason for the public key to be encrypted. It's public. It just >needs to be signed. You're right. I was thinking private key for whatever reason, instead of reading what you actually wrote. >>>I have some very nice diagrams of all of this that I commissioned >>>when I still thought I was going to apply for a patent. :-) Talk [quoted text clipped - 4 lines] >Thanks. I can't really complain: I had fun, and maybe some day I'll >get to use what I learned about the patent system. My experience with it came at no cost (and no gain) to me. I was working for an Army R&D lab at the time, and they paid for the patent processing, and provided the legal expertise. Of course, they got the rights to use it for Government purposes, and only if there was a private enterprise application would I get any possible royalties. Of course, there weren't. :-) Enjoy, DoN. SignatureEmail: <dnichols@d-and-d.com> | Voice (all times): (703) 938-4564 (too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html --- Black Holes are where God is dividing by zero --- >> And how about tossing in GPS info as well? > > Probably not a bad idea, if the camera is equipped to record GPS > info into the image (something which would be useful in some fields -- > including your spies. :-) There is at least one SLR that EXIF's GPS data into image file. I don't remember which. Signature-- r.p.e.35mm user resource: http://www.aliasimages.com/rpe35mmur.htm -- r.p.d.slr-systems: http://www.aliasimages.com/rpdslrsysur.htm -- [SI] gallery & rulz: http://www.pbase.com/shootin -- e-meil: there's no such thing as a FreeLunch. >>> And how about tossing in GPS info as well? >> [quoted text clipped - 4 lines] >There is at least one SLR that EXIF's GPS data into image file. I don't >remember which. Without a built-in GPS, how can you trust the GPS data? SignatureThat was it. Done. The faulty Monk was turned out into the desert where it could believe what it liked, including the idea that it bad been done by. It was allowed to keep its horse, since horses where so cheap to make. -- Douglas Adams in Dirk Gently's Holistic Detective Agency >> There is at least one SLR that EXIF's GPS data into image file. I >> don't remember which. > > Without a built-in GPS, how can you trust the GPS data? No built in GPS, just an interface. The EXIF *should* record the GPS state at the time of the info recording, including SV state data in order to have a verifiable signature of the GPS data tied to the image data. You'd then have to keep a copy of the Alamanac from the USCG (I'm not sure how far back their database goes). Indoors and in some poor geometry conditions/locations, the GPS will be useless of course, but that should be refelcted in the data. Finally, GPS data has not been required to date as part of testimony, Signature-- r.p.e.35mm user resource: http://www.aliasimages.com/rpe35mmur.htm -- r.p.d.slr-systems: http://www.aliasimages.com/rpdslrsysur.htm -- [SI] gallery & rulz: http://www.pbase.com/shootin -- e-meil: there's no such thing as a FreeLunch. >>> There is at least one SLR that EXIF's GPS data into image file. I >>> don't remember which. [quoted text clipped - 6 lines] >data. You'd then have to keep a copy of the Alamanac from the USCG (I'm >not sure how far back their database goes). As far as I know, NMEA data is trivial to forge. The camera should only sign things that cannot be forged. A trivial solution for forging data is to have a GPS at one place, send the data over the Internet or a mobile phone datalink to the camera and take a picture. The camera doesn't know where the GPS is. SignatureThat was it. Done. The faulty Monk was turned out into the desert where it could believe what it liked, including the idea that it bad been done by. It was allowed to keep its horse, since horses where so cheap to make. -- Douglas Adams in Dirk Gently's Holistic Detective Agency >>>>There is at least one SLR that EXIF's GPS data into image file. I >>>>don't remember which. [quoted text clipped - 9 lines] > As far as I know, NMEA data is trivial to forge. The camera should only > sign things that cannot be forged. SV state data (ephemeris) is not in the NMEA (AFAIK). I forgot to add range-rate information to the whole enchilada. The GPS OEM proprietary format would normally be used to xfer the detailed data. It is not impossible, but certainly not easy to forge SV state data and receiver range-rate info of a certain location and time without intimate knowledge of the GPS system (space segment included). > A trivial solution for forging data is to have a GPS at one place, send the > data over the Internet or a mobile phone datalink to the camera and take > a picture. The camera doesn't know where the GPS is. That's why my comment about "...if they didn't need it then..." and adding to that is, as the other poster said, once they have the person who took the shots in the witness stand, its pretty solid. Cheers, Alan Signature-- r.p.e.35mm user resource: http://www.aliasimages.com/rpe35mmur.htm -- r.p.d.slr-systems: http://www.aliasimages.com/rpdslrsysur.htm -- [SI] gallery & rulz: http://www.pbase.com/shootin -- e-meil: there's no such thing as a FreeLunch. >> As far as I know, NMEA data is trivial to forge. The camera should only >> sign things that cannot be forged. [quoted text clipped - 5 lines] >range-rate info of a certain location and time without intimate >knowledge of the GPS system (space segment included). I don't know. I have an old GPS. An it's NMEA format is documented in the manual. Nothing special. SignatureThat was it. Done. The faulty Monk was turned out into the desert where it could believe what it liked, including the idea that it bad been done by. It was allowed to keep its horse, since horses where so cheap to make. -- Douglas Adams in Dirk Gently's Holistic Detective Agency >>>As far as I know, NMEA data is trivial to forge. The camera should only >>>sign things that cannot be forged. [quoted text clipped - 8 lines] > I don't know. I have an old GPS. An it's NMEA format is documented in > the manual. Nothing special. NMEA is "utilty" level data. Most GPS engines (as opposed to the packaged GPS) have proprietry protocols that you can usually download from the engine OEM. Within those, the OEM allows you to tell the receiver to output a large amount of specific data. Some manufacturers are mor liberal than others with the content as some characteristics may reveal weaknesses of the receiver. However, there engines that do give you a lot of these internals. Within that, there are the precise ephemeris data (finer than the almanac data, and up to date (within the past 15 minutes, v. Almanac which may be 30 days old). Back in the S/A-on days, it was possible to make fine measurements of the satelite signal and record them; and then a week later, the Air Force would publish the history of the S/A activity such that the recorded data could be corrected and full accuracty could be restored by the user using various s/w techniques (The customers for this were typically surveyors. The specifics are too far back for me, but do google away..). I'm not sure if, in the post S/A era if those data are still published, or needed. Cheers, Alan Signature-- r.p.e.35mm user resource: http://www.aliasimages.com/rpe35mmur.htm -- r.p.d.slr-systems: http://www.aliasimages.com/rpdslrsysur.htm -- [SI] gallery & rulz: http://www.pbase.com/shootin -- e-meil: there's no such thing as a FreeLunch. >I think the expensive part is the public-key math -- which is still >not so bad since you're only signing a hash, not the message itself. >(Ok, I'm handwaving here, I'm not actually sure which is more costly.) On a low-end system (say Pentium-133) with slightly optimized C code, computing a SHA-256 hash is about 1 Mbyte/s. Computing a 2048-bit RSA signature takes about 5 seconds. I don't know how fast the CPUs are that they put cameras. SignatureThat was it. Done. The faulty Monk was turned out into the desert where it could believe what it liked, including the idea that it bad been done by. It was allowed to keep its horse, since horses where so cheap to make. -- Douglas Adams in Dirk Gently's Holistic Detective Agency > A PGP signature would take somewhat longer, and a full PGP >encryption of the entire file would take significantly longer -- so it [quoted text clipped - 9 lines] > Enjoy, > DoN. Don, I have "played" with PGP since 2.6.2, so I at least know a little about what you are writing about. However, if it gets to all this I will go into the storage room and find my old Speed Graphic. It would be cheaper and simpler. :) Also, I usually have an assistant along (for measurements ... and a little extra firepower) and she would be available to testify as to the photographs as well. It has not been necessary yet. Marty ... who is (at this hour) leaning towards the XT due to the lower cost primarily. I will probably shoot at 10mm wide open and manual focus at just below infinity. With 10mm it all should fall into dof, even wide open. Naturally I can bracket ISO and/or shutter speeds. After a few tests I should know if I need a tripod or not. I am pretty steady for an old geezer and I usually have a car or pole or wall to use as a brace. I usually make three sets of 5x7s since I like the jury to have a set in their hands rather than looking across the room at larger prints (if they are awake). You cannot look at prints and pass them along while you are asleep. And I believe there is something personal about having them in their hands. Thanks, Marty >> A PGP signature would take somewhat longer, and a full PGP >>encryption of the entire file would take significantly longer -- so it [ ... ] >Don, > >I have "played" with PGP since 2.6.2, so I at least know a little >about what you are writing about. However, if it gets to all this I >will go into the storage room and find my old Speed Graphic. It would >be cheaper and simpler. :) Sorry -- I got carried away with the "how" even after the need had been proven to be not present. >Also, I usually have an assistant along (for measurements ... and a >little extra firepower) and she would be available to testify as to >the photographs as well. It has not been necessary yet. Good enough. >Marty ... who is (at this hour) leaning towards the XT due to the >lower cost primarily. I will probably shoot at 10mm wide open and >manual focus at just below infinity. With 10mm it all should fall into >dof, even wide open. Of course your effective focal length (as determined by your coverage) will be 16mm, as contarasted with the 18mm for the Nikon with its widest setting being 12mm. But presumably, this should be sufficient. [ ... ] >wall to use as a brace. I usually make three sets of 5x7s since I like >the jury to have a set in their hands rather than looking across the >room at larger prints (if they are awake). You cannot look at prints >and pass them along while you are asleep. And I believe there is >something personal about having them in their hands. Have you ever had problems with the jury being confused by the perspective that you get with a really wide lens? Good Luck, DoN. SignatureEmail: <dnichols@d-and-d.com> | Voice (all times): (703) 938-4564 (too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html --- Black Holes are where God is dividing by zero --- > Have you ever had problems with the jury being confused by the >perspective that you get with a really wide lens? > > Good Luck, > DoN. Not a jury, but a judge. I had, about ten years ago, a non-jury trial in which I had used a 24mm on 35mm film and I had measured a distance to be 300 feet from where the police claimed to be when they allegedly saw a consented-to adult sex act in the bushes. My photographs (not altered in any way) did make it look like a greater distance. The judge said it was further than 300 feet and I must have not measured correctly. I insisted, and naturally the judge "won." Long story end was that my side won the case based on those WA views. The prosecutor failed to ask me what lens I was using. BTW, the police lied and said there were children at the location to try to make it look like some terrible crime. I had spent hours there, during a few trips, at the same time of day and day of week. No children. It was a walled-in private church park. It was a school day. I interviewed a Nun and she told me the same ... no children during school hours in the park. I think the judge knew the place and didn't believe the officer. Marty > Not a jury, but a judge. I had, about ten years ago, a non-jury trial > in which I had used a 24mm on 35mm film and I had measured a distance [quoted text clipped - 11 lines] > told me the same ... no children during school hours in the park. I > think the judge knew the place and didn't believe the officer. So what were you doing in the bushes again? ;) >> Not a jury, but a judge. I had, about ten years ago, a non-jury trial >> in which I had used a 24mm on 35mm film and I had measured a distance [quoted text clipped - 14 lines] >So what were you doing in the bushes again? >;) At my age I could only wish. :( >> Canon is working on (may have it on the market now, as I haven't been >> following the progress) a system that will be proof of authenticity for [quoted text clipped - 7 lines] > > http://www.dpreview.com/news/0401/04012903canondvke2.asp So, how does it work? I cannot find any details. > I was awfully chagrined when the DVK-E2's release was covered on > Slashdot about a year ago, as I had been working for several months > on a nearly identical invention. Canon and I even identified the You and me both.... -peter >I was awfully chagrined when the DVK-E2's release was covered on >Slashdot about a year ago, as I had been working for several months >on a nearly identical invention. Canon and I even identified the >same target markets: news, law enforcement, insurance, and spies -- >though they didn't mention spies in their press release. :-) Nobody in the thread seems to have mentioned research as a market. Half of the results in molecular biology come in the form of a gel electrophoresis that has to be photographed, because it can't be stored. And these days, scientific integrity is an omnipresent issue. It won't do allowing somebody to photoshop a critical band in or out. In the olden days, the gels were recorded by Polaroid cameras, the pictures of which were reasonably tamperproof. Today, there are designated CCD systems that are, or claim to be, tamperproof. But they are a great deal more expensive than an EOS 20D and a DVK-E2 kit. Jan Böhme Korrekta personuppgifter är att betrakta som journalistik. Felaktigheter utgör naturligtvis skönlitteratur. Jan Böhme wrote: > Nobody in the thread seems to have mentioned research as a market. > Half of the results in molecular biology come in the form of a gel > electrophoresis that has to be photographed, because it can't be > stored. And these days, scientific integrity is an omnipresent issue. > It won't do allowing somebody to photoshop a critical band in or out. The movie "Sikwood" with the nuklear fuel rod x-rays being retouched comes to mind... > In the olden days, the gels were recorded by Polaroid cameras, the > pictures of which were reasonably tamperproof. So keep doing the polaroids? Cheers, Alan Signature-- r.p.e.35mm user resource: http://www.aliasimages.com/rpe35mmur.htm -- r.p.d.slr-systems: http://www.aliasimages.com/rpdslrsysur.htm -- [SI] gallery & rulz: http://www.pbase.com/shootin -- e-meil: there's no such thing as a FreeLunch. >> In the olden days, the gels were recorded by Polaroid cameras, the >> pictures of which were reasonably tamperproof. > >So keep doing the polaroids? Practically nobody does, these days. Funding is tightening everywhere, and the accumulated cost of polaroid shots ishuge, even if you compare it with the writing off costs of a dedicated outfit for scientific gel photography costing from $12 000 upwards. According to Good Laboratory Practice, every gel, also the total failures, has to be documented. And if the bands are weak, you often need a couple of shots before you have what you want. Lots of polaroid shots. But of course, a 20D vith the DVK-E2 kit would be a lot cheaper still. Jan Böhme > > Finally I am going to switch from film totally. I am to either go > > Canon or Nikon and totally based on this WA question. I will do 85% of [quoted text clipped - 26 lines] > > Colin Since one can always use a digital camera and a film recorder the legal system has me bewildered! George >I don't now whether you do this 'officially' for police or legal >reasons, but if you will be in a position to rely on your shots as [quoted text clipped - 3 lines] >tampered with generally means it is harder to prove the image as >genuine. I have been hearing this stuff for years now. Most of the major police forces here in Canada have already switched to digital, in fact there was an article in Photo District News last year about the Winnipeg Police and RCMP using digital only, and I know that the Ontario Provincial Police uses digital imagery interchangeably with film. All the forensic technician or photographer is required to do, if asked, is testify that the image represents the scene as he saw it. The same thing they were asked to do with film. In my entire career I have never heard of a photographer having to produce a negative in court. >>I don't now whether you do this 'officially' for police or legal >>reasons, but if you will be in a position to rely on your shots as [quoted text clipped - 14 lines] >career I have never heard of a photographer having to produce a >negative in court. Thank you McLeod. I have been in court for 40 years myself and also have not had to produce any negatives. In the old days I used a 4x5 Speed Graphic and recorded f-stops, shutter speeds, film, developer, etc. No one ever asked me about that stuff either. My photos usually have to do with a view someone says they had. That is, an impossible view. |
Enable EMail Alerts
Start New Thread
Reply to this Message