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Photo Forum / Digital Photography / DSLR Cameras / December 2006DOF, Hyperfocal distance and my 'personal CoC'
Hola, I've been lurking this group from Spain for some time but this is my first post. I entered the DSLR world last year with a D50 and have recently upgraded to a D200 (perhaps too soon, too many buttons and options). Until my coin purse fills in a bit again, my only lens is a Nikkor 18-200 VR II. I'm by no means an 'expert' and I've learned a lot from reading you guys but, on the other hand, I some times think that with so much reading here and other places, my 'personal CoC' is getting larger and larger. This is why I decided to send my first post with a few, and perhaps naive, questions. 1.- About DOF. From what I've read in the ongoing 'Depth of Field' thread, I gather that DOF is referred to printing and that it varies with the size of the print. And my questions are: What's the 'DOF preview' button on my and another cameras for then? That I know of, it doesn't send any proof to the printer and get it back for me to look at, does it? Can I relay on what I see in the viewfinder? I know that what it does is step down the aperture to the selected one but, why is it called DOF _preview_ then? 2.- About Hyperfocal distance. I started with photography many years ago but then, when all my equipment was stolen, I had a many years break until I got my D50 last year. I remember that, mainly for landscapes, I would set the lens to hyperfocal and just forget about focusing. I see now that most modern lenses (at least those I have seen), specially those for DSLRs, don't even have the marks. My question is: With such sophisticated and accurate AF systems in modern DSLRs, wouldn't it be possible for a camera to set the lens to hyperfocal distance? Wouldn't it be a nice AF option to have? Is there any camera/lens that does it? If not, why not? TIA for your answers and comments.  SignatureUn saludo, Miguel > Hola, > [quoted text clipped - 19 lines] > does is step down the aperture to the selected one but, why is it called > DOF _preview_ then? Depth of field depends on focal length and aperture. check this out: http://www.cs.mtu.edu/~shene/DigiCam/User-Guide/950/depth-of-field.html > 2.- About Hyperfocal distance. I started with photography many years ago > but then, when all my equipment was stolen, I had a many years break [quoted text clipped - 6 lines] > it be a nice AF option to have? Is there any camera/lens that does it? > If not, why not? I suppose it would be possible, but it would mean changing the focus as the aperture changes, and knowing exactly the focal length being used at any given time. This is a lot of extra gimmicry for very little result, leaving a wide margin for error. It would also slow down the focusing system, as it would first have to find the exact focus and then defocus according to a hyperfocal algorithm. The last thing anyone wants is to slow down autofocusing. Besides that, one of the points of creative photography is to selectively defocus elements (usually the background). One doesn't always want everything in focus. Besides this hyperfocal distance is predicated on an "acceptable" CoC, which means that your subject is at less than maximum sharpness when using the hyperfocal distance. All in all it is not an option I would want on a DSLR, or rather, there are quite a number of other things I would choose first for the time, money and material that would have to be invested in such an option. Toby > TIA for your answers and comments. >> 1.- About DOF. From what I've read in the ongoing 'Depth of Field' >> thread, I gather that DOF is referred to printing and that it varies [quoted text clipped - 6 lines] > > Depth of field depends on focal length and aperture. Depth of field also depend on acceptable Circle of Confusion. The acceptable Circle of Confusion is dependend on several parameters, but in general it often comes close to 1/1500 of the diagonal of the endresult. You might be more critical, you might be less critical. Because the acceptable Circle of Confusion is often considered dependend on the size of the diagonal, it is dependend on the frame size (or crop size) as wel. The acceptable Circle of Confusion is dependend on the eyesight of the observer, on the enlargement and on the viewing distance of the final result. ben > check this out: > [quoted text clipped - 31 lines] >> >> TIA for your answers and comments. Hola Ben, On 23/12/2006, at 21:29, you wrote: >> Depth of field depends on focal length and aperture. >> [quoted text clipped - 7 lines] > size) > as wel. > The acceptable Circle of Confusion is dependend on the eyesight of the > observer, on the enlargement and on the viewing distance of the final > result. I fully agree with you Ben. SignatureSaludos, Miguel > Hola Ben, > [quoted text clipped - 16 lines] > > I fully agree with you Ben. Absolutely true. Toby Hola Toby, On 23/12/2006, at 17:21, you wrote: >> 1.- About DOF. From what I've read in the ongoing 'Depth of Field' >> thread, I gather that DOF is referred to printing and that it varies [quoted text clipped - 4 lines] >> does is step down the aperture to the selected one but, why is it called >> DOF preview then? > Depth of field depends on focal length and aperture. Oh come on, I know that. It was covered in lesson 1 of my "Simple Photography for Advanced Idiots" handbook (or was it "Advanced Photography for Simple Idiots"?) ;-) >> 2.- About Hyperfocal distance. I started with photography many years ago >> but then, when all my equipment was stolen, I had a many years break [quoted text clipped - 14 lines] > hyperfocal algorithm. The last thing anyone wants is to slow down > autofocusing. It shouldn't slow down the focusing system, much the contrary. It would not need to focus and then defocus, etc. All it would take is that CPU in the lens know "where infinity is" in the focusing ring and where are the "aperture marks" are (actually only one of them) and how it "moves" with the different focal lengths if the lens is a zoom, so that upon getting a command from the camera (i.e. pushing a button) it could align both marks. Seems rather simple to me with today's electronics and technology. > Besides that, one of the points of creative photography is to selectively > defocus elements (usually the background). One doesn't always want [quoted text clipped - 4 lines] > I would choose first for the time, money and material that would have to be > invested in such an option. I wasn't talking about 'creative photography' as you call it, I was just talking about using (setting to) hyperfocal distance for landscaper (or whatever). Aside of that, an option in a camera does not mean that _you_ or anyone have to use it. It is just another option, like for example WB bracketing which I hardly or never use (specially if shooting RAW). SignatureSaludos, Miguel > does it? Can I relay on what I see in the viewfinder? I know that what it > does is step down the aperture to the selected one but, why is it called > DOF _preview_ then? It gives you an idea of the overall effect in a comparative sense. > 2.- About Hyperfocal distance. I started with photography many years ago > but then, when all my equipment was stolen, I had a many years break [quoted text clipped - 6 lines] > it be a nice AF option to have? Is there any camera/lens that does it? > If not, why not? 1) Manual focus with manual focus lenses is more accurate than AF. 2) AF (in most cameras/lenses) is not aware of the focus "distance" that it is setting. The AF, per the phase information in the AF sensor simply drives the focus one way or the other until cancellation is achieved. Not many lenses give the focus 'setting' of the lens back to the camera. So an auto "hperfocal distance" button or function would not be feasible. (Note some lenses, such as Minolta DI (Distance Integrated) lenses could possibly do this, however the accuracy of the "distance" information might be too coarse for setting hyperfocal. (It is used in the Minolta system to aid flash exposure). 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: Remove FreeLunch. > 1) Manual focus with manual focus lenses is more accurate than AF. I have heard this in the past and have a question. What do you base this on? I have spent a lot of time with a Minolta XD7, so I think I know how accurate manual focus is. Now I have a Nikon D200, and cannot say that I have ever found AF inaccurate in any meaningful sense. I have had it misfocus grossly, yes, but never appear to focus and then turn out to be slightly off. I currently have 4 lenses, and have the same experience on all of them. That is, if I zoom to, say, 100% in photoshop, I don't find that the thing I focused on is slightly unsharp but something else sharp. It may focus on the wrong thing (if the selected sensor covers more than one object, and at different distances), but it simply has never happened to me that it has focused on the right thing but focus is slightly off (ie the main subject is slightly unsharp). The same can be said of my 7xi, but of course I have never looked at slides under so much magnification. So, here's the question: What, exactly, does it mean to say that MF is more accurate than AF? In practical terms. Thanks. >>1) Manual focus with manual focus lenses is more accurate than AF. > So, here's the question: What, exactly, does it mean to say that MF is > more accurate than AF? In practical terms. I'll answer it the other way around: why is AF less accurate than MF on a MF lens: 1) The hysteresis necessary to allow the AF control to stop "hunting". 2) The "looser" focus mechanism to allow electric motors to move the focus ring w/o consuming a lot of power (also makes MF on an AF camera a little less easy, esp. combined with the lack of a split prism focus indicator). For a lot of photography it doesn't matter much as the DOF is greater than the AF focus error. 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: Remove FreeLunch. > > So, here's the question: What, exactly, does it mean to say that MF is > > more accurate than AF? In practical terms. [quoted text clipped - 11 lines] > For a lot of photography it doesn't matter much as the DOF is greater > than the AF focus error. Yes, all this is fine, but in practical terms, I don't see it. Or are we talking about f/stops faster than f/1.8 on a 50mm? Because what I say is certainly true for my 50mm f/1.8 (ie it I can see no focus error at 100% at f/1.8). So, as far as I can tell, it will be visible with longer lenses and/or faster f/stops. Or does this statement perhaps mean something else than I think? > Yes, all this is fine, but in practical terms, I don't see it. Or are > we talking about f/stops faster than f/1.8 on a 50mm? Because what I > say is certainly true for my 50mm f/1.8 (ie it I can see no focus error > at 100% at f/1.8). So, as far as I can tell, it will be visible with > longer lenses and/or faster f/stops. When you use autofocus to focus on something, you're putting the focusing area in the viewfinder somewhere and then telling the camera to focus on that. But the focus areas are large, and the camera could focus anywhere within the one being used. So, even if the autofocus is absolutely exact (which it may or may not be), it could still be off from what you want despite being "correct". SignatureJeremy | jeremy@exit109.com > > Yes, all this is fine, but in practical terms, I don't see it. Or are > > we talking about f/stops faster than f/1.8 on a 50mm? Because what I [quoted text clipped - 8 lines] > exact (which it may or may not be), it could still be off from what you > want despite being "correct". Well yes, I understand this. But on my D200 the AF marks aren't all that large, the system isn't sensitive outside them (unless you choose wide AF), and anyway that's a different story from AF errors due to tolerances in lenses and so on. I did indeed have this problem with a 7xi I have (which had larger sensors). I was just wondering whether people routinely see AF problems (in the sense of focusing on the right thing but getting it a bit wrong in terms of distance) and I am just lucky, or whether it is less of a problem than it sounds. Sure, it will only focus with some tolerance, and probably the acceptable focus error is larger than a pixel, but I see no problems at f/1.8 and 50mm, so... Or maybe I just haven't noticed it. I don't know. > Well yes, I understand this. But on my D200 the AF marks aren't all > that large, the system isn't sensitive outside them (unless you choose > wide AF), and anyway that's a different story from AF errors due to > tolerances in lenses and so on. I did indeed have this problem with a > 7xi I have (which had larger sensors). The AF areas are still larger than some things you might want to focus on. This is one area where I see focus errors most frequently. (The other is when there's not enough light.) > I was just wondering whether people routinely see AF problems (in the > sense of focusing on the right thing but getting it a bit wrong in [quoted text clipped - 3 lines] > see no problems at f/1.8 and 50mm, so... Or maybe I just haven't > noticed it. I don't know. I think some lenses are more accurate than others. I don't typically see a problem with it, but the lenses where you'd be more likely to see a problem (like a 50/1.8) are probably designed to be accurate to within what they need for f/1.8. But an f/5.6 lens might not be made to be as accurate, on the assumption that any error would be within the depth of field at maximum aperture. I haven't done controlled testing, but this is my conclusion just based on normal use. Sometimes it feels like it's focusing within a tolerance rather than precisely. In my own experience, though, the focusing errors I see are typically due to the camera focusing on something other than what I want. SignatureJeremy | jeremy@exit109.com > In my own experience, though, the focusing errors I see are typically > due to the camera focusing on something other than what I want. Yes, I get that too sometimes. If the thing you wish to focus on is smaller than the AF sensor, and surrounded by other objects which are closer, I don't really see what can be done. MF is out of the question for me without a split screen, and, from what I hear, split screens for DSLRs create slight problems for spot metering; this is more important than a split screen to me, so I just put up with it. > Yes, I get that too sometimes. If the thing you wish to focus on is > smaller than the AF sensor, and surrounded by other objects which are > closer, I don't really see what can be done. MF is out of the question > for me without a split screen, and, from what I hear, split screens for > DSLRs create slight problems for spot metering; this is more important > than a split screen to me, so I just put up with it. I have a split-prism focusing screen from Katz Eye in my D2x, and it is said only to affect spot metering with lenses slower than f/4. Their web site says f/3.5 for the D200. This isn't something I miss since most of my lenses aren't affected -- but the focusing screen is the best thing ever. SignatureJeremy | jeremy@exit109.com > > Yes, I get that too sometimes. If the thing you wish to focus on is > > smaller than the AF sensor, and surrounded by other objects which are [quoted text clipped - 8 lines] > most of my lenses aren't affected -- but the focusing screen is the > best thing ever. Hmm... This sounds tempting. How is the installation? >> I have a split-prism focusing screen from Katz Eye in my D2x, and it is >> said only to affect spot metering with lenses slower than f/4. Their [quoted text clipped - 3 lines] > >Hmm... This sounds tempting. How is the installation? About as easy as it gets. They supply a plastic tweezers, and it's hard to miss. (I keep the old screen in the plastic container, with the tweezers, in my laptop bag...) The only problem I've had with mine is interesting though, but is not unique to the Katz Eye screen. I brought a cooler than I realized camera into a warmer/damper room than I realized, and water darn near dripped off the camera before I noticed... A long story made short, the AF system failed to recover. After two days of "drying out", it was focusing significantly off. I was concerned that it would take a $400 trip to a Nikon repair facility to fix! But I figured I'd take a look and see what is in the viewfinder with the focusing screen removed. Ha, that was an eye opener! It took one glance and about 1/2 second to realize the "fix" was just count to 100 and put it all back together. The focusing screen is in direct contact with a glass surface, and if moisture gets between them, it simply isn't going to evaporate... until the focusing screen is removed. Then it should take mere seconds in a warm dry environment for both surfaces to dry out. It turns out the Katz Eye screen is as good as I expected, given the claims made for it, but in my case only half as useful as I'd hoped (which isn't really bad...). I like it very much for hand held use with a manual focus lense. The AF focus indicator works, but it is hard to use because it is down in the corner of the viewfinder. I generally focus looking at the screen, and then glance down to see of the AF indicator agrees. That's fine. But it turned out that any time the camera is tripod mounted, I just simply find it easier to use the AF indicator. That works when tripod mounted only because checking the indicator isn't likely to cause a change in framing. SignatureFloyd L. Davidson <http://www.apaflo.com/floyd_davidson> Ukpeagvik (Barrow, Alaska) floyd@apaflo.com > It turns out the Katz Eye screen is as good as I expected, given > the claims made for it, but in my case only half as useful as [quoted text clipped - 7 lines] > That works when tripod mounted only because checking the > indicator isn't likely to cause a change in framing. What was an eye-opener (so to speak) for me was the range over which the AF system thinks it's in focus when, according to the split-prism, it is clearly not. I love my 50mm f/1.2 lens, but I'm not sure an autofocus version would be too great. Autofocus just doesn't seem to be precise enough. I don't even pay attention to the green-light AF indicator any more, when manually focusing. The Katz Eye screen was the best money I've spent on photography since the camera itself. I can't say enough good things about it. SignatureJeremy | jeremy@exit109.com > > It turns out the Katz Eye screen is as good as I expected, given > > the claims made for it, but in my case only half as useful as [quoted text clipped - 19 lines] > spent on photography since the camera itself. I can't say enough good > things about it. OK, your and Floyd's replies are very useful to me, as I had more or less discounted these screens on the grounds of interfering with spot metering. I'll have to reconsider. Thanks. > OK, your and Floyd's replies are very useful to me, as I had more or > less discounted these screens on the grounds of interfering with spot > metering. I'll have to reconsider. Thanks. If you use a lot of lenses slower than f/3.5 (on the D200) then the screen will interfere with spot metering using those lenses. Also, if your lenses are usually that slow I would recommend getting the extra brightness treatment they offer. All the lenses I use regularly are at least f/2.8, so for me there's no real downside. Metering works perfectly and autofocus operation is not affected. My only "slow" lens is a 300mm, and I'm not likely to use spot metering with that anyway. SignatureJeremy | jeremy@exit109.com >OK, your and Floyd's replies are very useful to me, as I had more or >less discounted these screens on the grounds of interfering with spot >metering. I'll have to reconsider. Thanks. I don't really expect a light meter to be accurate. It is, *if* and *only* if the object is 18 percent gray. I can't tell within even 1 fstop, maybe 1-1/2, what is 18 percent gray and what isn't. I use the "blink on over exposure" LCD display, which easily allows repeatable precision and accuracy within 1/3 of an fstop. SignatureFloyd L. Davidson <http://www.apaflo.com/floyd_davidson> Ukpeagvik (Barrow, Alaska) floyd@apaflo.com > >OK, your and Floyd's replies are very useful to me, as I had more or > >less discounted these screens on the grounds of interfering with spot [quoted text clipped - 7 lines] > I use the "blink on over exposure" LCD display, which easily > allows repeatable precision and accuracy within 1/3 of an fstop. I don't need accuracy either, but I do want repeatability. However, what I do (when I have time) is spotmeter off whatever it is that I want to be the brightest non-overexposed object in my picture, then add 2.3 stops (I've checked and, with my raw converter, daylight white balance and usual settings, this is what I can tolerate without overexposure and without doing acrobatics during conversion). If spotmetering using the centre sensor gives a different result than spotmetering off one of the other sensors, shooting would become more complicated for me. So I'd like to find out whether this focusing screen affects all sensors equally (thus no problem, I just need to recalibrate myself) or not (problem). > So I'd like to find out whether this focusing screen affects all > sensors equally (thus no problem, I just need to recalibrate myself) > or not (problem). Unfortunately, the only lens I have that is supposed to be affected by this is a non-CPU manual focus lens, and when using those, spot metering only works using the center point. So I am unable to test this for you. However, I just tried some tests with the lens, a 300mm f/4.5, and the spot metering is pretty close; it looks to me like it's overexposing by a stop or so. I pointed it at a lamp (very bright) and took a shot, and the resulting exposure didn't put the metered area on middle gray, but it was not very far off, certainly not enough to make it useless. You should be able to adjust for it mentally, assuming it's consistent. SignatureJeremy | jeremy@exit109.com > > So I'd like to find out whether this focusing screen affects all > > sensors equally (thus no problem, I just need to recalibrate myself) [quoted text clipped - 11 lines] > > You should be able to adjust for it mentally, assuming it's consistent. OK, thanks for the info. I'd appreciate it if anybody could check whether this is consistent between focus points (and if it's constant). >>For a lot of photography it doesn't matter much as the DOF is greater >>than the AF focus error. [quoted text clipped - 4 lines] > at 100% at f/1.8). So, as far as I can tell, it will be visible with > longer lenses and/or faster f/stops. AF is independant of the aperture chosen for the shot and totally dependant on the fastest aperture of the lens. Faster lenses (like an f/1.8) get a lot of light from the subject compared to, eg: a f/3.5). eg: an f/3.5 lens is receiving less light than the f/1.8 lens and so the contrast at the AF sensor is lower and the errors consequently larger. Another reason to buy fast glass if you use AF. > Or does this statement perhaps mean something else than I think? Try 3/4 portraits at 100mm f/2.8 and get the nearest eye tack sharp and the further eye soft (or v.v.). Other than the contorsions of doing so with AF, it may reveal some error in the AF system. On a 50mm f/1.8 it will be easier to get that focus becasue more light is available to the AF sensor. (To be fair, I would hope AF systems today are better than those of 1990.) 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: Remove FreeLunch. > >>For a lot of photography it doesn't matter much as the DOF is greater > >>than the AF focus error. [quoted text clipped - 12 lines] > contrast at the AF sensor is lower and the errors consequently larger. > Another reason to buy fast glass if you use AF. But I just meant that if there is some error, then it'll be more visible at a faster aperture than at a slower one (with the same focal length etc etc). > > Or does this statement perhaps mean something else than I think? > [quoted text clipped - 5 lines] > > (To be fair, I would hope AF systems today are better than those of 1990.) Well, for portraits I almost always use a 90mm f/2.8, and see no problems at all. But perhaps there are errors and what is happening is the following: if the f/stop I used is largish (eg 3.5 on a 50mm) they are masked by the DOF. Now, I do use f/1.8 on my 50mm, and f/2.8 on the 90mm, but only when I am at the limits of handholding; what I do is shoot a few frames at 5 fps, review at 100%, and delete the unsharp ones, assuming it's shake. Well, maybe some of them are just focus error (now that I think of it, some could be; they are not obvious shake). Anyway, I personally can't manually focus without a split screen at all, and have no problems using AF, so... But I was always wondering why I don't see errors, as I don't really think the AF system uses a 6 micron circle of confusion. Maybe that's the answer. Or maybe not! Anyway, merry Christmas! >>>>For a lot of photography it doesn't matter much as the DOF is greater >>>>than the AF focus error. [quoted text clipped - 16 lines] > visible at a faster aperture than at a slower one (with the same focal > length etc etc). And I was just pointing out the complexity of drawing conclusions: Yes, the DOF will be shallowest at fastest aperture and thus make errors more apparent; OTOH, the more generous dose of light will help the AF system be more accurate. >>Try 3/4 portraits at 100mm f/2.8 and get the nearest eye tack sharp and >>the further eye soft (or v.v.). Other than the contorsions of doing so [quoted text clipped - 14 lines] > shake. Well, maybe some of them are just focus error (now that I think > of it, some could be; they are not obvious shake). I always shoot 'formal' (that is to say a deliberate portrait) with a tripod for various reasons including DOF-on-target. I never machine gun. > Anyway, I personally can't manually focus without a split screen at > all, and have no problems using AF, so... But I was always wondering Matt screen manual focusing needs bright contrast light. Doing it in a relatively subdued lighting studio is very tough. But this applies to the AF system as well: more light=better focus. > why I don't see errors, as I don't really think the AF system uses a 6 > micron circle of confusion. Maybe that's the answer. Or maybe not! > Anyway, merry Christmas! And to you! 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: Remove FreeLunch. Hola Alan, On 23/12/2006, at 18:44, you wrote: >> does it? Can I relay on what I see in the viewfinder? I know that what it >> does is step down the aperture to the selected one but, why is it called >> DOF preview then? > It gives you an idea of the overall effect in a comparative sense. I understand that. I was somewhat trying to make a joke with the fact that it is called "preview" in regards to those who maintain that DoF varies with the size (enlargement) of the print. The "absolute" value of the CoC diameter does vary with the size of the enlargement but, to measure DoF, this diameter has to be considered "relative" to the diagonal of the print. Or, in other words, the distance from which you should look at different print sizes should vary so the "angle of vision" is the same for all sizes. >> 2.- About Hyperfocal distance. I started with photography many years ago >> but then, when all my equipment was stolen, I had a many years break [quoted text clipped - 8 lines] > > 1) Manual focus with manual focus lenses is more accurate than AF. I don't know if that statement is really true or not. I would say that it may depend on how good is the AF system being considered and how good is the vision of the photographer. > 2) AF (in most cameras/lenses) is not aware of the focus "distance" that > it is setting. The AF, per the phase information in the AF sensor [quoted text clipped - 5 lines] > "distance" information might be too coarse for setting hyperfocal. (It > is used in the Minolta system to aid flash exposure). See my reply to Toby. If I understand it correctly, hyperfocal distance is that which, for a given aperture and focal length, would achieve focus (acceptable CoC) from a distance closer to the camera than the hyperfocal one to infinity and, for that, the camera/lens does not need to AF or know the distance where it would AF. Actually, the whole idea of setting the lens to hyperfocal distance is to achieve 'good focus' from a certain distance to infinity so there is no need to AF to any point/subject and should be faster than AFing. SignatureSaludos, Miguel > Hola Alan, > > On 23/12/2006, at 18:44, you wrote: >>1) Manual focus with manual focus lenses is more accurate than AF. > > I don't know if that statement is really true or not. I would say that > it may depend on how good is the AF system being considered and how good > is the vision of the photographer. I'm not going to debate the point, it has been discussed ad nauseum. If there is an AF system that is demonstrably more accurate than MF (in the hands of sombody who knows what they are doing) I haven't heard about it. >>2) AF (in most cameras/lenses) is not aware of the focus "distance" that >>it is setting. The AF, per the phase information in the AF sensor [quoted text clipped - 14 lines] > from a certain distance to infinity so there is no need to AF to any > point/subject and should be faster than AFing. 1) As said: Hyperfocal distance is a function of focal length and aperture. For a given aperture and focal length, the hyperfocal focus distance changes, getting closer to the camera with higher aperture numbers (smaller aperture). 2) To automate the function (as you wish), the "automat" (by any name) needs to know the distance at which the lens is focused. As the great majority of lenses do not provide that feedback, such a function is not feasible. And even in the few lenses that do provide that function, it is likely too coarse. You don't need to call it "AF" but you do need to drive the lens to the correct focus distance to be hyperfocal. Without a measure of the focus distance in the lens the automated function simply cannot be implemented. I hope that that is clear enough? 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: Remove FreeLunch. >> See my reply to Toby. If I understand it correctly, hyperfocal distance >> is that which, for a given aperture and focal length, would achieve [quoted text clipped - 19 lines] > correct focus distance to be hyperfocal. Without a measure of the focus > distance in the lens the automated function simply cannot be implemented. Maybe all that's needed is basically a lookup chart on the top LCD menu that tells you the closest focus and hyperfocal distance for the current aperture and focal length. Then you can look at the distance markings on the lens to focus, all lenses have those. It would be most convenient on the top LCD so you can see it while focusing to lens markings and twiddling aperture. It couldn't be used for general DOF unless your lens reports focus distance, which most do not or unless it's in the back menu as a little calculator function where you can twiddle focal distance... which would still have to be manually set on most lenses. Hola Alan, On 24/12/2006, at 15:14, you wrote: >>>1) Manual focus with manual focus lenses is more accurate than AF. >> >> I don't know if that statement is really true or not. I would say that >> it may depend on how good is the AF system being considered and how good >> is the vision of the photographer. > I'm not going to debate the point, it has been discussed ad nauseum. If > there is an AF system that is demonstrably more accurate than MF (in the > hands of sombody who knows what they are doing) I haven't heard about it. I had no intention of debating the point or questioning your statement, I was just stating my lack of knowledge about it. >>>2) AF (in most cameras/lenses) is not aware of the focus "distance" that >>>it is setting. The AF, per the phase information in the AF sensor [quoted text clipped - 19 lines] > distance changes, getting closer to the camera with higher aperture > numbers (smaller aperture). Right, that I got clear. > 2) To automate the function (as you wish), the "automat" (by any name) > needs to know the distance at which the lens is focused. As the great [quoted text clipped - 7 lines] > > I hope that that is clear enough? Let me first say that English is my second language and that I could some times misunderstand what you guys say and/or perhaps not express myself clearly enough. That said, I understand that you are saying that the lenses would need to have some kind of 'internal distance scale' that would allow the camera to read where the distance ring is at so that it could move it from that point to to the HF distance, and that there would be no need of AFing to any subject prior to setting the lens to HF distance, as I may have understood in other postings. Now, in one of my earlier posts I said that with today's technology I assume it should not be too difficult or costly to implement what I have called 'internal distance scale' in lenses, 'HF distance table or calculation' in the camera (or in the lens itself), etc. But there must be something wrong in my assumption when manufactures don't include these in any (or most) of their lenses and cameras. SignatureSaludos, Miguel > Hola Alan, > > I understand that you are saying that > the lenses would need to have some kind of 'internal distance scale' > that would allow the camera to read where the distance ring is at There aren't that many lenses with this feature. I don't know about Canon but look at the Nikon lineup: http://www.nikonusa.com/template.php?cat=1&grp=5 the ones with a 'D' report the focus ring info back to the camera for the purpose of calculating flash, and I suppose kind of nice to have in the exif data... for example 24-85mm f/2.8-4D IF AF Zoom-Nikkor I'm not sure why none of the 'G' lenses have this. G means no aperture ring so I guess you can read the markings on those. Hola Paul, On 25/12/2006, at 17:35, you wrote: >> I understand that you are saying that >> the lenses would need to have some kind of 'internal distance scale' >> that would allow the camera to read where the distance ring is at > There aren't that many lenses with this feature. I don't know about > Canon but look at the Nikon lineup: [quoted text clipped - 4 lines] > I'm not sure why none of the 'G' lenses have this. G means no aperture > ring so I guess you can read the markings on those. As I have read in 'nikon europe', both the D and G lenses report the focus distance back to the camera. They actually say that "all modern AF lenses" do so. However, I have never seen it included in the exif data, at least with the D50 or D200. SignatureSaludos, Miguel > As I have read in 'nikon europe', both the D and G lenses report the > focus distance back to the camera. They actually say that "all modern > AF lenses" do so. However, I have never seen it included in the exif > data, at least with the D50 or D200. it is definitely there. using exiftool, here are selected tags from three random pictures from a nikon d50: F Number : 5.3 Focus Distance : 7.94 m Depth of Field : 2.11 m (7.03 - 9.13) Focal Length : 80.0mm (35mm equivalent: 120.0mm) Hyperfocal Distance : 60.28 m F Number : 7.1 Focus Distance : 7.94 m Depth of Field : 10.15 m (5.34 - 15.49) Focal Length : 48.0mm (35mm equivalent: 72.0mm) Hyperfocal Distance : 16.20 m F Number : 8.0 Focus Distance : 2.82 m Depth of Field : inf (1.09 m - inf) Focal Length : 17.0mm (35mm equivalent: 25.0mm) Hyperfocal Distance : 1.77 m >>As I have read in 'nikon europe', both the D and G lenses report the >>focus distance back to the camera. They actually say that "all modern >>AF lenses" do so. However, I have never seen it included in the exif >>data, at least with the D50 or D200. > > it is definitely there. Irfanview gives 'SubjectDistanceRange' as 'Unknown' Photoshop gives zero. I tried the ExifTool and got the same info as you for a D200 & a G lens. That would be handy on the image review and certainly easy to implement. > using exiftool, here are selected tags from three random pictures from > a nikon d50: [quoted text clipped - 16 lines] > Focal Length : 17.0mm (35mm equivalent: 25.0mm) > Hyperfocal Distance : 1.77 m Hola nospam, On 26/12/2006, at 16:42, you wrote: >> As I have read in 'nikon europe', both the D and G lenses report the >> focus distance back to the camera. They actually say that "all modern >> AF lenses" do so. However, I have never seen it included in the exif >> data, at least with the D50 or D200. > it is definitely there. > using exiftool, here are selected tags from three random pictures from > a nikon d50: > F Number : 5.3 > Focus Distance : 7.94 m > Depth of Field : 2.11 m (7.03 - 9.13) > Focal Length : 80.0mm (35mm equivalent: 120.0mm) > Hyperfocal Distance : 60.28 m You are very right! I tried with exiftool a couple of weeks ago but, as I found out today, it was an old version. I downloaded 6.66 a while ago and voila! As you say the 'Focus Distance', DoF, Focal Length, HF distance, etc., are there. However, the 'SubjectDistanceRange' is also reported as 'unknown' and I guess this is what most other programs display as part of exif data. Anyway, this all means the information is sent from the lens to the camera and it is recorded. So, when in some of my posts in this thread I said that this should be possible (and perhaps easy) with current technology, I was right. It is possible. But now I wonder even more why the heck the (or some) cameras don't have a button (or AF option) to set the lens (focus) to HF distance? The same AF motor(s) could be used for this. SignatureSaludos, Miguel > Anyway, this all means the information is sent from the lens to the > camera and it is recorded. So, when in some of my posts in this thread I [quoted text clipped - 3 lines] > the lens (focus) to HF distance? The same AF motor(s) could be used for > this. One problem is that the distance reported is not accurate. The lens reads distance in "zones", and there are only so many of those (a dozen or so), within which the same distance is always reported. You can see in the examples given previously, that two of the pictures reported the exact same distance, out to two decimal places. If you start looking through your pictures (taken with lenses that report distance) you will find that you are seeing the same numbers over and over. That the distances are given with two decimal places is misleading; it is not accurate to that precision. So it *could* be done, provided a distance-reporting lens is in use, but it would have to be somewhat "rough" in its implementation. Which may not be any kind of problem in real-world use; the information is probably accurate enough for a landscape, as long as you're happy with the sharpness you get using hyperfocal distance. SignatureJeremy | jeremy@exit109.com Hola Jeremy, On 27/12/2006, at 1:11, you wrote: >> Anyway, this all means the information is sent from the lens to the >> camera and it is recorded. So, when in some of my posts in this thread I [quoted text clipped - 3 lines] >> the lens (focus) to HF distance? The same AF motor(s) could be used for >> this. > One problem is that the distance reported is not accurate. The lens reads > distance in "zones", and there are only so many of those (a dozen or so), [quoted text clipped - 5 lines] > given with two decimal places is misleading; it is not accurate to that > precision. You are probably right. I wouldn't expect the camera/lens to be as accurate as one of those laser measuring devices. But I haven't checked enough pictures to see how many 'zones' the 'distance scale' has. > So it could be done, provided a distance-reporting lens is in use, but > it would have to be somewhat "rough" in its implementation. Which may > not be any kind of problem in real-world use; the information is probably > accurate enough for a landscape, as long as you're happy with the > sharpness you get using hyperfocal distance. All options have some kind of trade off that one should be aware about before using it. SignatureSaludos, Miguel > Hola Paul, > [quoted text clipped - 10 lines] > AF lenses" do so. However, I have never seen it included in the exif > data, at least with the D50 or D200. Well that is odd. Hola Paul, On 26/12/2006, at 16:57, you wrote: >> As I have read in 'nikon europe', both the D and G lenses report the >> focus distance back to the camera. They actually say that "all modern >> AF lenses" do so. However, I have never seen it included in the exif >> data, at least with the D50 or D200. > Well that is odd. But, as you have reported you have seen with exiftool, it seems to be true, SignatureSaludos, Miguel > Hola Alan, > > On 24/12/2006, at 15:14, you wrote: >>1) As said: Hyperfocal distance is a function of focal length and >>aperture. For a given aperture and focal length, the hyperfocal focus [quoted text clipped - 18 lines] > some times misunderstand what you guys say and/or perhaps not express > myself clearly enough. Your english is fine enough. > That said, I understand that you are saying that > the lenses would need to have some kind of 'internal distance scale' > that would allow the camera to read where the distance ring is at so > that it could move it from that point to to the HF distance, and that > there would be no need of AFing to any subject prior to setting the lens > to HF distance, as I may have understood in other postings. Well I wasn't perfectly clear the first time 'round. This does not need to be part of the AF system (as I implied the first time) but it does require enough information to accomplish the function. > Now, in one of my earlier posts I said that with today's technology I > assume it should not be too difficult or costly to implement what I have > called 'internal distance scale' in lenses, 'HF distance table or > calculation' in the camera (or in the lens itself), etc. But there must > be something wrong in my assumption when manufactures don't include > these in any (or most) of their lenses and cameras. It can be done, but there is no reverse compatibility route. As you likely know, but I'll state it anyway: Good lenses have the focus distance v. aperture scale marked on the lens and by simply matching the focus infinity mark to the "long" aperture mark then hyperfocal (for about an 8x10 print) is achieved immediately. It is dead simple as that and does not require any automation to achieve it. As Paul mentions, work arounds could be used, but I think the basic system as provided is more than adequate. 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: Remove FreeLunch. Hola Alan, On 25/12/2006, at 19:20, you wrote: > As you likely know, but I'll state it anyway: Good lenses have the focus > distance v. aperture scale marked on the lens and by simply matching the > focus infinity mark to the "long" aperture mark then hyperfocal (for > about an 8x10 print) is achieved immediately. It is dead simple as that > and does not require any automation to achieve it. Yes, of course I know. As I have stated somewhere else in this thread, that is what I used to do with my 35mm equipment many years ago (before it was stolen) to shoot landscape diapos. I would set to HF distance for the selected aperture and thus 'know' that from a certain distance (half of HF) on to infinity everything would be in acceptable focus. And that is why I have missed this possibility when I entered the 'DSLR world' recently and wondered why, given today's technology, no camera seems to offer the possibility of, at the press of a button, set the lens to HF distance for the selected (manually or automatically) aperture and focal length. This was one of the reasons I wrote my first message that started this thread. SignatureSaludos, Miguel > 1.- About DOF. From what I've read in the ongoing 'Depth of Field' > thread, I gather that DOF is referred to printing and that it varies [quoted text clipped - 4 lines] > does is step down the aperture to the selected one but, why is it called > DOF _preview_ then? I think the assumption is always for an 8x10 print. Experiment with the DOF preview button at 200mm closest distance in bright light at different apertures and you will see the effect more clearly. With a very small f/22 aperture it gets too dark to see what's going on and it's less noticeable at longer distances. > 2.- About Hyperfocal distance. I started with photography many years ago > but then, when all my equipment was stolen, I had a many years break [quoted text clipped - 6 lines] > it be a nice AF option to have? Is there any camera/lens that does it? > If not, why not? Well those marks were on the aperture ring and newer Nikon 'G' lenses don't even have an aperture ring. I guess it might be a nice idea to have the DOF read out in the viewfinder but there is already so much info crammed in there. It would only work with 'D' lenses as Alan described, and many lenses do not report the distance. It would be really complicated to produce a window on the lens that showed DOF... the camera would have to do the calculating & the lens would need another little motor in there to adjust it. Here's a neat little interactive demo to refresh your understanding of DOF & hyperfocal: http://beej.us/guide/bgp/dof.html Hola Paul, On 23/12/2006, at 20:14, you wrote: >> 1.- About DOF. From what I've read in the ongoing 'Depth of Field' >> thread, I gather that DOF is referred to printing and that it varies [quoted text clipped - 4 lines] >> does is step down the aperture to the selected one but, why is it called >> DOF preview then? > I think the assumption is always for an 8x10 print. Experiment with the > DOF preview button at 200mm closest distance in bright light at > different apertures and you will see the effect more clearly. With a > very small f/22 aperture it gets too dark to see what's going on and > it's less noticeable at longer distances. Yes, an 8x10 print if the acceptable CoC diameter is given as an 'absolute' value. And no need to experiment, I used DoF preview in my 35mm cameras many years ago and it is always the same story, DoF is too shallow at full aperture and, when stepping down to minimum aperture, the viewfinder is to darn dark to see DoF ;) Actually, I hardly use DoF preview button, except for some close-ups or to fire the 'modelling flash' with my SB-600. > Here's a neat little interactive demo to refresh your understanding of > DOF & hyperfocal: http://beej.us/guide/bgp/dof.html I think I understand DOF and hyperfocal distance and that, as can be seen in that demo, hyperfocal distance is "fixed" for each aperture/focal length pair, no matter where you actually focus the lens. SignatureSaludos, Miguel > Hola Paul, > [quoted text clipped - 22 lines] > preview button, except for some close-ups or to fire the 'modelling > flash' with my SB-600. Agreed DOF preview is really only useful for closeups or fast telephotos with blurred backgrounds close to wide open. Not much use for getting a landscape correct at hyperfocal distance. Especially on smaller DSLR viewfinders. On my old film SLR, I could judge landscapes reasonably well. >>Here's a neat little interactive demo to refresh your understanding of >>DOF & hyperfocal: http://beej.us/guide/bgp/dof.html > > I think I understand DOF and hyperfocal distance and that, as can be > seen in that demo, hyperfocal distance is "fixed" for each > aperture/focal length pair, no matter where you actually focus the lens. OK so for the hypothetical hyperfocal button, you set the zoom and aperture/shutter in whatever mode you are using then the HF button autofocuses to the hyperfocal distance and gives that distance in the viewfinder. If the distance is 200 feet away & you want more foreground, then it's up to you to stop down & have it re-set the HF. Hmm, there is some distance in front of the HF also, and some behind if you aren't at HF so the viewfinder needs three distance numbers. Or, a simple green 'HF' that lights up in the viewfinder when you are within range, and use the DOF preview to judge foreground sharpness. Hola Paul, On 24/12/2006, at 20:58, you wrote: >>>Here's a neat little interactive demo to refresh your understanding of >>>DOF & hyperfocal: http://beej.us/guide/bgp/dof.html >> >> I think I understand DOF and hyperfocal distance and that, as can be >> seen in that demo, hyperfocal distance is "fixed" for each >> aperture/focal length pair, no matter where you actually focus the lens. > OK so for the hypothetical hyperfocal button, you set the zoom and > aperture/shutter in whatever mode you are using then the HF button [quoted text clipped - 3 lines] > some distance in front of the HF also, and some behind if you aren't at > HF so the viewfinder needs three distance numbers. Personally I wouldn't need any distance reported on the LCD or viewfinder as long as I knew the lens had been set to HF distance. But if anything was to be reported, I would be happy with just the minimum distance. Maximum would always be infinity and who cares where HF actually is. SignatureSaludos, Miguel > Hola Paul, > [quoted text clipped - 18 lines] > distance. Maximum would always be infinity and who cares where HF > actually is. You seem to imply that HD is single distance for any given lens. In fact, there is a HD for every stop and every focal length of lens. If you change the aperture, the HD will change also. The practical application of dof and HD is to ensure that what you want in focus is actually within the COC parameters, and for a given lens, you do that by choosing an appropriate aperture. Since by definition the DoF extends from half the HD to infinity, the lens will need to know how far it is to the nearest point you want in focus. The only way I can see for this to happen is the way Canon does it, by actually measuring the nearest and farthest points, so it has the data needed to do the calculations. Without knowledge of the closest part of the scene you want to be in focus, the lens does not have sufficient data to make the calculation. Colin D. PS: Your English is better than some of the English-first-language posters in the group. SignaturePosted via a free Usenet account from http://www.teranews.com Hola Colin_D, On 26/12/2006, at 0:18, you wrote: >> Personally I wouldn't need any distance reported on the LCD or >> viewfinder as long as I knew the lens had been set to HF distance. But [quoted text clipped - 5 lines] > fact, there is a HD for every stop and every focal length of lens. If > you change the aperture, the HD will change also. No, not at all. If you think that is what imply it probably is because I have not expressed correctly. It is perfectly clear for me (since my old 35mm days many years ago) that HF varies with aperture and focal distance. It is 'fixed' for a given aperture/focal distance pair, though. <snipped a bit> > Without knowledge of the closest part of the scene you want to be in > focus, the lens does not have sufficient data to make the calculation. No, it's the other way around. I want to set HF distance, period. Then, if possible, the camera/lens should let me know (or give me a hint) which is the closest distance (HF/2) with 'acceptable' focus. Just like the DoF scale marks do on some lenses when you set HF distance manually. SignatureSaludos, Miguel > No, it's the other way around. I want to set HF distance, period. Then, > if possible, the camera/lens should let me know (or give me a hint) > which is the closest distance (HF/2) with 'acceptable' focus. Just like > the DoF scale marks do on some lenses when you set HF distance manually. I'm sure that you're capable of a rough division by 2? 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: Remove FreeLunch. Hola Alan, On 26/12/2006, at 21:52, you wrote: > I'm sure that you're capable of a rough division by 2? Not really, I was never too good with divisions. I'd rather multiply by 0.5 ;) SignatureSaludos, Miguel > Hola, > [quoted text clipped - 15 lines] > thread, I gather that DOF is referred to printing and that it varies > with the size of the print. Not really. I can't say it has nothing to do with printing, but it is seldom really an issue with printing. We are all a little loose with talking about DOF and what it means. That is made even more complex because DOF can refer to Depth of Field or Depth of focus, and they are NOT the same thing. You did refer to Depth of Field, but did you really mean that or could you have meant Depth of Focus? > And my questions are: What's the 'DOF > preview' button on my and another cameras for then? It gives you an approximate idea of what the results will look like. Not exact for a number of reasons and those reasons may be different with different cameras. I am intentionally not trying to give a precise answer. You appear to be looking for a precise answer in the world of art. Sort of like asking an famous photographer what exact color of blue you should use for a sky. There is no one right answer. Use your camera and play with all the settings. Learn how each effects the results. Try to isolate them at first then start mixing them. Don't let the science rule the art. > That I know of, it > doesn't send any proof to the printer and get it back for me to look [quoted text clipped - 14 lines] > > TIA for your answers and comments. SignatureJoseph Meehan Dia 's Muire duit Hola Joseph, On 23/12/2006, at 22:06, you wrote: >> 1.- About DOF. From what I've read in the ongoing 'Depth of Field' >> thread, I gather that DOF is referred to printing and that it varies >> with the size of the print. > Not really. I can't say it has nothing to do with printing, but it is > seldom really an issue with printing. > We are all a little loose with talking about DOF and what it means. > That is made even more complex because DOF can refer to Depth of Field or > Depth of focus, and they are NOT the same thing. You did refer to Depth of > Field, but did you really mean that or could you have meant Depth of Focus? I was referring to Depth of Field. To tell you the truth, I think it probably the first time I hear about Depth of Focus and it being something different to DoF. But I have done a little googling and you are right, this are couple of the many definitions I've found: ,----- [ Depth of field ] | The amount of distance between the nearest and farthest objects that | appear in acceptably sharp focus in a photograph. Depth of field depends | on the lens opening, the focal length of the lens, and the distance from | the lens to the subject. `----- ,----- [ Depth of focus ] | The distance range over which the film could be shifted at the film | plane inside the camera and still have the subject appear in sharp | focus; often misused to mean depth of field. `----- >> And my questions are: What's the 'DOF preview' button on my and >> another cameras for then? > > It gives you an approximate idea of what the results will look like. > Not exact for a number of reasons and those reasons may be different > with different cameras. I think I have explained enough about what I meant in other replies in this same thread. SignatureSaludos, Miguel > Hola, > [quoted text clipped - 10 lines] > This is why I decided to send my first post with a few, and perhaps > naive, questions. 'Personal CoC' - I like that! Good phrase! > 1.- About DOF. From what I've read in the ongoing 'Depth of Field' > thread, I gather that DOF is referred to printing and that it varies [quoted text clipped - 4 lines] > does is step down the aperture to the selected one but, why is it called > DOF _preview_ then? The purpose of using a CoC calculation is to more or less ensure that the finished print is acceptably sharp over the depth of field required. The variables of the camera sensor size, any cropping of the image, and subsequent magnification required to produce the print to your chosen standard will affect the CoC as seen by the sensor. Nikon recommends an actual CoC of 0.020 mm at the sensor for average use. The dof as seen with the dof button is very approximate, just to get an idea. Being able to see 0.020 mm in the viewfinder is impracticable. > 2.- About Hyperfocal distance. I started with photography many years ago > but then, when all my equipment was stolen, I had a many years break [quoted text clipped - 6 lines] > it be a nice AF option to have? Is there any camera/lens that does it? > If not, why not? Some Canon slrs (film and digital)have a feature called 'DEP', whereby you align one focus sensor on the nearest object you want within the dof, and another sensor on the farthest object, and take a half-pressure on the trigger. The camera calculates the focal point (the HD if the far object is at infinity) and sets the lens to that point. Then, switch the lens to manual so the focus won't change, compose the shot (without moving the zoom or focus) and take it. The focal calculation is instant. For taking shots like large groups where there may be three or four rows of people, it is invaluable, and likewise for scenic shots with a close foreground. As a Canon man, I can't speak for other makes, and some may have similar functions. Colin D. > TIA for your answers and comments. SignaturePosted via a free Usenet account from http://www.teranews.com Hola Colin_D, On 24/12/2006, at 2:40, you wrote: > 'Personal CoC' - I like that! Good phrase! :-)) >> 1.- About DOF. From what I've read in the ongoing 'Depth of Field' >> thread, I gather that DOF is referred to printing and that it varies [quoted text clipped - 14 lines] > with the dof button is very approximate, just to get an idea. Being > able to see 0.020 mm in the viewfinder is impracticable. Yes, I think I understand all of than now. >> 2.- About Hyperfocal distance. I started with photography many years ago >> but then, when all my equipment was stolen, I had a many years break [quoted text clipped - 21 lines] > As a Canon man, I can't speak for other makes, and some may have similar > functions. That seems like a real nice functionality I didn't know about. I would be nice to have it but, don't ask me why because I have no real reason, I've never paid much attention to any Canon cameras. Thank you and all who replied to my post. And... Merry Xmas to all! SignatureSaludos, Miguel |
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