 |
 | 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 / January 2005D70 focus problems??
When I compare the pictures from my D70 and my PowerShopt G3 the G3 pictures seems very much sharper. This is the case even when I increase the sharpness in the settings. Maybe, it's hard to say for sure, there is a little back focus. By the way, this is with the 19-70 kit lens. I'll do some research tomorrow to see if there is an actual bacfocus. Anyone else with the same problem? /erik > When I compare the pictures from my D70 and my PowerShopt G3 the G3 > pictures seems very much sharper. This is the case even when I increase > the sharpness in the settings. Maybe, it's hard to say for sure, there > is a little back focus. By the way, this is with the 19-70 kit lens. Are you shooting the same subject with both? Same aperture and shutter speed? Tripod or handheld? Any examples?  SignatureColm >>When I compare the pictures from my D70 and my PowerShopt G3 the G3 >>pictures seems very much sharper. This is the case even when I increase [quoted text clipped - 4 lines] > speed? Tripod or handheld? > Any examples? To be honest I haven't investigated it to that degree. It is more a of a thing I've noticed when I compare pictures from the two cameras. I have a large number of very crisp G3 pictures, and none of the D70 pictures are as sharp. My feeling is that the use of a tripod does not make any difference. I'll put some examples on my webserver - will post the URL later. /erik Now I have done some tests comparing my G3 to my D70 with 18-70 kit lens. The G3 lens is 35-140mm eqiv with aperture 2.0-3.0. The D70 18-70 is 3.5-4.5 with a 27-105 eqiv (1.5 crop factor). I compared the D70 (with the 18-70) to the G3 at the same aperture and at each cameras/lens wide angle resp telephoto limit using a home made focusing chart. I used a tripod. At wide angle one of the objects on my test chart had a size of 65 mm on the G3 and 70 mm on the D70 (roughly the same distance between the sensors and the object). The D70 image was however very much larger in the objects direction so the D70 picture thus corresponds to a smaller focal distance. It is however of importance below when I compare the resolution, since even though the objects on the G3 were smaller in terms of number of pixels they occupied, the resolution and sharpness seemed to be the same as with the D70! I found the percieved sharpness about equal as well as the resolution (that is, if a could tell 2 points apart in one of the pictures I could do the same in the other). There was some sharpening artefacts in both images and none were better than the other. The G3 had a larger DOF (but you could take the G3 down to aperture 2.0 if you want a small DOF). The D70 DOF was quite a bit back, but the object I focused on where in focus (maybe there were a very slight back focus). The G3 thus performed equally well as the D70 even though the objects on the G3 was a little smaller (in of number of pixels). At the telephoto limit one object where 233mm in the G3 and 191 mm in D70. The G3 picture was virtually free from sharpening artefacts whereas the D70 had some halos (I set the D70 sharpening to medium high). In this test the resolution of the G3 was superior to the D70, possibly because of the larger tele. I found the sharpness to be better in the G3 picture (but not by much) as well. In this test the D70 focused accuratly with about equal DOF at both sides. Again, the G3 had a larger DOF (but you could be set the aperture to 3.5 instead of the tested 4.5). When it comes down to a pixel by pixel comparision, that is if a object takes up the same number of pixels, the G3 seems superior. The G3 had no problems with setting the correct focus (besides being much slower), but D70 18-70 had some minor problems. I have some problems explaining the larger DOF of the G3, especially since it were more in the telephoto range, but I guess this is because of the smaller optics that can be used secondarily to the smaller CCD. There was some focusingproblems when using the D70 with the kit lens, and the G3 seemed overall a little bit sharper (pixel by pixel), but I can't say that this was because of bad focusing. This test does not explain the differences I've seen before! /erik >There was some focusingproblems when using the D70 with the kit lens, What do you mean by this? Sounds like you are are near or at the close focusing limit of the kit lens, ie 1.2 ft. ________________________________________________________ Ed Ruf Lifetime AMA# 344007 (Usenet@EdwardG.Ruf.com) See images taken with my CP-990/5700 & D70 at http://EdwardGRuf.com If that's the case, it would make me happy! I'll try to do the test again tomorrow at a larger distance. However, I think I was farther from the focus point than 40 cm but I can't remember for sure. I got a "focus lock" on objects much nearer the focus point (i didn't take any photos!!!), and there was no problem at 70 mm even though the distance from the focus point to the sensor was the same. I could be badly wrong here! It would be nice if you could give me an explanation in that case, ie why wasn't there any "problems" at 70 mm when it was at 35 mm. Anyhow, as I explained, the AF could not (if we extrapolate the test results to larger distances) be the reason that the pictures from the D70 looks less sharp (pixel wise) since the the focus point always were in focus (although the DOF was more to the back at 18 mm). /erik >>There was some focusingproblems when using the D70 with the kit lens, > [quoted text clipped - 4 lines] > See images taken with my CP-990/5700 & D70 at > http://EdwardGRuf.com > It would be nice if you could give me an >explanation in that case, ie why wasn't there any "problems" at 70 mm >when it was at 35 mm. If you are shooting at anything les than the 40cm min focal distance I have no idea. This is one area where a dslr with most lenses is not as capable as a P&S. I still use my 990 and 570 when I need real macro shots. Jus used my 900 the last few days fro shots within 3 in. My D70 won't do that. ________________________________________________________ Ed Ruf Lifetime AMA# 344007 (Usenet@EdwardG.Ruf.com) See images taken with my CP-990/5700 & D70 at http://EdwardGRuf.com I'll do the test from a greater distance tomorrow. It could be that I was to near. My g3 is superior to the 18-70 in macro as well. My brother has a nikon mikro 60 mm that i'm going to borrow the next time i meet him. Could be fun to test some makro photography with the d70. /erik > If you are shooting at anything les than the 40cm min focal distance I have > no idea. This is one area where a dslr with most lenses is not as capable [quoted text clipped - 4 lines] > See images taken with my CP-990/5700 & D70 at > http://EdwardGRuf.com >When I compare the pictures from my D70 and my PowerShopt G3 the G3 >pictures seems very much sharper. This is the case even when I increase [quoted text clipped - 4 lines] > >Anyone else with the same problem? I believe there was a back focus issue with early models. ________________________________________________________ Ed Ruf Lifetime AMA# 344007 (Usenet@EdwardG.Ruf.com) See images taken with my CP-990/5700 & D70 at http://EdwardGRuf.com I got the camera in august 2004 and it has (and had from the beginning) the latest? (A 1.01 B 1.02) firmware. As I understand, it was a new camera (they had to order it for me) and not something that had been in the store for a long time. Wasn't it the very first cameras that had the focus problem? Did this problem persist until late summer 2004? It could be that there is more in camera sharpening in the powershot, but I can't see any halos on the photos. The AF systems is different in campact and SLR digitals as far as I know. The photos are all taken with AF so this _maybe_ could have some impact - guessing here though... I'll try to investigate this further and make my own focus test shart. /erik >>When I compare the pictures from my D70 and my PowerShopt G3 the G3 >>pictures seems very much sharper. This is the case even when I increase [quoted text clipped - 10 lines] > See images taken with my CP-990/5700 & D70 at > http://EdwardGRuf.com > When I compare the pictures from my D70 and my PowerShopt G3 the G3 > pictures seems very much sharper. This is the case even when I increase [quoted text clipped - 4 lines] > > Anyone else with the same problem? This guy claims to have a test for it. You might want to give it a try. http://md.co.za/d70/chart.html#ActualChart Thank you! /erik > This guy claims to have a test for it. You might want to give it a try. > > http://md.co.za/d70/chart.html#ActualChart >> When I compare the pictures from my D70 and my PowerShopt G3 the G3 >> pictures seems very much sharper. This is the case even when I increase [quoted text clipped - 8 lines] > >http://md.co.za/d70/chart.html#ActualChart He only tests the center horizontal focusing sensor. Wouldn't it be prudent to test each one separately?, there are 5 others. -- Owamanga! There is lens sharpness and digital sharpness. You can compare manual to autofocusing on your own to see if the autofocus is really the problem. The D70 at default jpg settings seems to apply significantly less sharpening than P&S and prosumer cameras and ramps up the contrast much less, all of which affects apparent image sharpness. Also the physically very small apertures in lenses used for smaller sensor cameras will tend to increase depth of field and apparent sharpness regardless of the focal length of the lens. However, comparing raw images of the same subject from a Nikon D70 and a Sony 828 I find there is an undeniable softness to the raw image coming off the Nikon D70 compared to the Sony 828 that is not simply due to the difference in megapixel count between the sensors, using the Adobe raw plug-in for both cameras rather than the Nikon/Sony raw converters and trying to use equivalent focal lengths and apertures. I do not know if this is a sensor or software issue: it is possible that in-camera processing is applied to the raw image differently in both cameras. > There is lens sharpness and digital sharpness. > You can compare manual to autofocusing on your own to see if the autofocus [quoted text clipped - 14 lines] > in-camera processing is applied to the raw image differently in both > cameras. Interesting! If the only difference between the both raw formats are the softness then Nikon is using an inferior CCD or bad processing. I found the D70 to be less sharp (not much) than the G3 _even_ though there were a little bit more halos in the D70 image. That's compatible with your findings. The sharpening algorithms etc have to work harder. The relative lack of sharpness could be the result of bad sharpening algorithms etc, but in the light of your findings it is more likely to be the quality of the input to the sharpening algorithms that is the cause. To my knowledge Canon is leading the pro digital SLR league at the cost of high prices. The D70 should however compete well against the EOS 300D, and generally be a better by even though it's a little bit more expensive. I haven't seen any nice and well done comparison between the two when it comes to image quality (with kit lenses) though. 300D will not have as much noise, but apart from that what should one expect?? I don't know if I could do better then the AF system. When I look through the viewfinder in AF mode my impression is that of good focusing. On the other hand, my test showed that there really were no (or at the very most very slight) back focusing at the very wide angle of the lens and no problems at all at the tele end of the lens. It seems that the focusing isn't the problem (if there are any problem :)). My tests could not explain the differences I see in my other photos. Maybe I'm just wrong and the cause is that I have so much more G3 photos and among all these, there are some that are perticulary well. /erik > There is lens sharpness and digital sharpness. > You can compare manual to autofocusing on your own to see if the autofocus [quoted text clipped - 14 lines] > in-camera processing is applied to the raw image differently in both > cameras. >When I compare the pictures from my D70 and my PowerShopt G3 the G3 >pictures seems very much sharper. How exactly are you comparing these different sized (pixel wise) images? ________________________________________________________ Ed Ruf Lifetime AMA# 344007 (Usenet@EdwardG.Ruf.com) See images taken with my CP-990/5700 & D70 at http://EdwardGRuf.com The first comparisions where more of "this one was sharp at 100% pixelwise, lets see what the D70 pictures look like. Hmm, that one wasn't as sharp, neither that or that or that... I have heard of a D70 back focusing problem. Could it be so, or is it something else.". The latest comparision was more systematic. I took a number of pictures at the telephoto and wide angle ends of both the G3 and the D70 18-70 and compared them. At wide angle there were little difference in the sizes (pixel wise) of objects in the picture. (se another post) At the telephoto end however there were since the G3 has a longer 35mm eqiv. I guess you want to tell me that the D70 is sharper than the G3 since a more "correct" test would be to compare the pictures at equal sizes (disregarding the different width to height ratios). This is of course one way to compare the pictures. One important factor is however how much one can crop and increase the size of the pictures. A test comparing pictures pixel wise is thus important, as it tells me that some of my extra pixels won't give me an increase in picture size but are "wasted". Then, as a bonus, I think it is interesting to try to find out why an image that occupies roughly the same number of photodetectors in the two cameras differ in terms of percieved sharpness (well, if it had done so more than it did :) ) /erik >>When I compare the pictures from my D70 and my PowerShopt G3 the G3 >>pictures seems very much sharper. [quoted text clipped - 4 lines] > See images taken with my CP-990/5700 & D70 at > http://EdwardGRuf.com >I guess you want to tell me that the D70 is sharper than the G3 since a >more "correct" test would be to compare the pictures at equal sizes >(disregarding the different width to height ratios). No, I'm trying to understand exactly what you are comparing, 1:1 pixel comparisons taken how? raw, jpeg, what settings?or something else. I own a Nikon 990, 570 and a D70. I still use all three. > This is of course >one way to compare the pictures. One important factor is however how >much one can crop and increase the size of the pictures. A test >comparing pictures pixel wise is thus important, as it tells me that >some of my extra pixels won't give me an increase in picture size but >are "wasted". Yes, but you need to compare consistent processing. Try this test with all in camera processing turned off. Not just sharpening, but any contrast, brightening or saturation, etc. processing. >Then, as a bonus, I think it is interesting to try to find out why an >image that occupies roughly the same number of photodetectors in the two >cameras differ in terms of percieved sharpness (well, if it had done so >more than it did :) ) I've done this with my 990/5700 and now my D70. You need to turn all in camera processing off to have any hope of a true unbiased comparison. ________________________________________________________ Ed Ruf Lifetime AMA# 344007 (Usenet@EdwardG.Ruf.com) See images taken with my CP-990/5700 & D70 at http://EdwardGRuf.com > No, I'm trying to understand exactly what you are comparing, 1:1 pixel > comparisons taken how? raw, jpeg, what settings?or something else. I own a > Nikon 990, 570 and a D70. I still use all three. Ok, at first it was just pictures, mostly jpegs, taken with the two cameras. Settings varied. Not systematic in any way. Then I tried to understand if the AF was to blame - and it is probably not. As an "extra" I tried to see if there was any differences in picture quality with the settings I had applied to both cameras or if it just happened to be that among the more numerous G3 pictures I was lucky to find a couple that looked very sharp. To me it seemed like the G3 pictures where sharper even in the more standardized setting and in one instance had lesser sharpening artefacts - wich I find interesting. No clue to why though. >>This is of course >>one way to compare the pictures. One important factor is however how [quoted text clipped - 6 lines] > in camera processing turned off. Not just sharpening, but any contrast, > brightening or saturation, etc. processing. Agree. >>Then, as a bonus, I think it is interesting to try to find out why an >>image that occupies roughly the same number of photodetectors in the two [quoted text clipped - 3 lines] > I've done this with my 990/5700 and now my D70. You need to turn all in > camera processing off to have any hope of a true unbiased comparison. Agrees mostly. But I think it is interesting to see how the camera processing works as well. Is one camera introducing more halos without incresing the "sharpness" compared to another camera etc. I'm only at the very beginning of the investigation, and later I'll try to see if I can locate the part, if any, to blame. For the moment I'm just having a number of pictures from the D70 and the G3 where the G3 pictures seems sharper pixel wise. My firts hypothesis was that the AF didn't work as expected since there's been a lot of talk about the D70 AF. But the test I've done indicates that the AF seems to work. But was there really a difference in sharpness or was it only a random occurence that hit me? But even using this more standardized procedure I found that the G3 pictures looked sharper (and I could do this test at the same time as the AF test). Thus, it isn't likely that it was just some random effect that i noticed earlier. Accordingly i find there is reason to investigate this further. But so far I'm just guessing the reason of this sharpness difference - maybe it's the postprocessing, maybe the CCD, maybe the lens. I haven't come that far yet. The next step will for certain involve comparing the cameras with no postprocessing in raw mode! Thank you for the advice! In the end I want to take as nice pictures as possible with as little postprocessing as possible for most of them, leaving me more time to postprocess only the nicest pictures. > ________________________________________________________ > Ed Ruf Lifetime AMA# 344007 (Usenet@EdwardG.Ruf.com) > See images taken with my CP-990/5700 & D70 at > http://EdwardGRuf.com Well the one thing you need to note is the aperture of the image. If you shoot at wide open apertures on the D70, and the G3 uses smaller apertures than the G3 will be more sharp. Also you are at the mercy of the lens on this, which is very good, so that is not an issue. I would look to see which images are not very sharp on the D70 and note the aperture. The sharper images will be around f/8-f/11. If using the G3 on auto modes, it may automatically select shutter speeds that put it at f/8-f/11 for sharper images. If shooting the D70 in portrait mode, then it will use the largest aperture it can for out of focus backgrounds. So it may select f/4. If this happens, less of the image is in focus, and the lens is not at it's optimum sharpness. These things are what I think are happening. The D70 is an awesome camera and it's output is among the best in this price range. If you want a sharper lens, get the 50/1.8 Nikkor. At $100 it's the best you could spend. Sharp, fast, light. Better than ANY zoom you can buy at any price. If you want a zoom, then look into a 28-70/2.8 AF-S Nikkor. At like $1500. Awesome lens, but that 50/1.8 is sharper and better. It also teaches you to not rely on the zoom and be more creative, enhancing your photography skills. JR > When I compare the pictures from my D70 and my PowerShopt G3 the G3 > pictures seems very much sharper. This is the case even when I increase [quoted text clipped - 6 lines] > > /erik I like the D70 very much. The one thing I don't like is the softer look of the pictures, but I guess I could change my workflow and get as sharp pictures as from the G3. It's hard to compare the D70 and G3 since the G3 gives a very much larger DOF at the same aperture. As I understand, this is because of the smaller optics. My comparison was however based on the sharpness at the focus point. The reason so far could be anything, but less likely the AF system. I'll investigate this futher. I have been thinking about buying the 50/1.8. It's a little bit more expensive here in sweden (about $150), but it is not much money anyway. The 28-70/2.8 is however rather expensive here (about $2500). I'll absolutly be thinking of buying the 50/1.8. Thanks for the advice. /erik > Well the one thing you need to note is the aperture of the image. If > you shoot at wide open apertures on the D70, and the G3 uses smaller [quoted text clipped - 17 lines] > > JR I have now compared the cameras (d70 and powershot g3) in raw mode. When comparing 2 jpegs you compare the in camera processing and the actual tuning of the in camera processing as well as other aspects of the camera. Another problem exists when comparing raw, because then you suddenly have off camera software for raw processing. This software differ - some programs do a better job for a certain raw format etc. Even if you use the same program for the raw processing, the tuning of the software could differ between different types of raw formats. I used photoshop camera raw to do the comparison. This even though nicon capture maybe could do a better job. The both raw pictures, without any sharpening or contrast enhancement etc, looked about the same. Since they were rather soft, it was hard to see if one or the other was softer. I tried to see any differences, but they looked very much the same in terms of sharpness. When applying the same amount of sharpening (as judged by the camera raw plugin settings) when converting the files from raw, the pictures where almost identical in terms of per pixel sharpness.... My conclusion to the D70 soft picture "problem" is thus that the in camera tuning for jpeg processing will give you softer looking pictures in the D70. The reasons for the conclusion are, as stated above, the more or less identical softness of the low processed raws, the almost identical sharpness of the sharpened raws and the fact that I could not see any back or front focus in my focus tests of the D70. It would affect the reasoning to some degree if camera raw in any way differed to the advantage of either of the cameras. /erik > When I compare the pictures from my D70 and my PowerShopt G3 the G3 > pictures seems very much sharper. This is the case even when I increase [quoted text clipped - 6 lines] > > /erik > My conclusion to the D70 soft picture "problem" is thus that the in camera > tuning for jpeg processing will give you softer looking pictures in the > D70. I think you are exactly right. This problem has taken several people by surprise during the time I've been reading this and related newsgroups. Professional cameras do much less enhancement by themselves than point-and-shoot cameras. The camera assumes that it has a much better lens (hence not as much need for sharpening) and that the image is going to be processed with software under the user's control. Are there settings to tell the D70 to do more sharpening? On the Digital Rebel you have adjustable in-camera sharpening. > Are there settings to tell the D70 to do more sharpening? Yes. In fact, the D70 has manual settings for almost everything. However, if you use one of the program modes, you get the settings for that particular program. There are 7 sharpening levels: none, low, medium low, normal, medium high, high, and auto. Auto is the default mode. Merritt >When I compare the pictures from my D70 and my PowerShopt G3 the G3 >pictures seems very much sharper. This is the case even when I increase >the sharpness in the settings. Maybe, it's hard to say for sure, there >is a little back focus. By the way, this is with the 19-70 kit lens. Try it with some other lenses. The try using manual focus. (Use a tripod to get the best images. If necessary even go as far as using the remote or self timer to key it. I ended up sending mine in under warranty as it would no longer focus to infinity. That affected the focus at other ranges as well. it took about two weeks and it came back with the latest firm ware at the time. Roger Halstead (K8RI & ARRL life member) (N833R, S# CD-2 Worlds oldest Debonair) www.rogerhalstead.com >I'll do some research tomorrow to see if there is an actual bacfocus. > >Anyone else with the same problem? > >/erik I have done some testing and my conclusions are that there is no significant back focusing in my camera. The reason for the softer looking pictures is likely to be a less agressive, compared to G3, in camera default sharpening. /erik >>When I compare the pictures from my D70 and my PowerShopt G3 the G3 >>pictures seems very much sharper. This is the case even when I increase [quoted text clipped - 19 lines] >> >>/erik |
Reply to this Message |
 Sign In
 Join
 My Latest Posts My Monitored Threads My Blog My Photo Gallery My Profile My Homepage Start New Thread Enable EMail Alerts Rate this Thread
|
©2009 Advenet LLC Privacy Policy - Terms of Use
This website includes both content owned or controlled by Advenet as well as content owned or controlled by third parties.