johnv

I read about that but thought that only had to do with the 1dIII not the 1DsIII like the camera body I have.

Thanks again, William :-)

I did the same test as above, this time defocusing AF between shots and this time there were 5 unsharp photos out of 56 - much improved compared to when I did not defocus between shots - and really, almost good enough for my usage. I checked around online and it seems this is not so unusual for this camera. I would definitely have liked it to be completely sharp every time but do realize that at least some of the unsharp photos from my real life shoots have been user error (something that is probably unavoidable until one can use AI Servo for everything) - and maybe I will try to not try to click on the AF twice as this yields more unsharp photos than only clicking once at the same distance to the object being photographed. https://photos.app.goo.gl/Kz2n4QnJf3ZCNNvUA Unsharp photos: 52 80 87 93 94 A few more of the shots were not critically sharp but sharp enough for most use circumstances so I didn't count them in the bunch of unsharp photos. Any other recommendations? Thanks for your help. William. It is much appreciated.

OK, I'll test it, defocusing between shots today or tomorrow. Thanks.

Thanks for your help, William. I did not defocus AF between shots. I have a feeling that might have helped a little but I don't know. Anyways, I just talked to the official local Canon repair shop and they say the newest camera they can still repair is the 1DX - they recently stopped repairing the 1DIV. This means one can expect repairs for about 7 years using professional Canon cameras. Not that long, methinks. He said it might be the AF sensor that was "tired" but that he couldn't fix it for me without new spare parts and that he didn't know of anyone that could get the parts for such old cameras. I guess that ends everything right here. I'll use the camera until I get a new one, eventually - and take lots of extra shots to compensate for AF problems. It would probably be too expensive to repair anyways - I have no idea.

Did the same test above using my EOS 1D Mark II and all photos were sharp with almost zero variation. I realize the camera has a lot fewer megapixels so this is less demanding on critical sharpness. However, many of the unfocused shots on my 1Ds Mark III are out of focus by more than just a little. Zero unsharp photos using the 50mm and 35mm from above : https://photos.app.goo.gl/eUbdbsY9Xv3TsSvj8 https://photos.app.goo.gl/ZvJCikcZ8RuMq58o7 Is there anything else I can do before taking the camera in for repairs?

BTW, I only used central AF point, Single Shot AF, tripod - so I only checked focus critically at the center point. I think that the 85 1.8 USM works well with this camera, the rest of my tested lenses, not so much, especially not the EF 35 IS USM. I guess I should try the lenses on a different camera body. I do in fact have an old 1D Mark II. I do shallow depth of field portraits from time to time and have noticed some problems with both back and front focusing.

I did the same test with the 35 2.0 IS USM and found 18 shots out of 56 that were unsharp. https://photos.app.goo.gl/UiPanw8duVPfUBzM8 Unsharp shots: 5292 5297 5300 5306 5307 5308 5311 5315 5317 5319 5320 5328 5329 5330 5337 5341 5344 5345 Quite a lot more of the shots were not completely sharp at 100% but only reasonably sharp.

I did the same test with the EF 100 2.8 IS USM and found 6 unsharp shots out of 51 shots: https://photos.app.goo.gl/fjEdTMDgoADVF4M27 Unsharp shots: 5240 5241 5244 5245 5246 5256 I did see even more variation between shot sharpness than with the 85mm but I decided only to select the photos that were clearly unsharp.

I did the same test with the EF 85 1.8 USM and found 1 unsharp photo of 50 using AF. https://photos.app.goo.gl/hzYSt2jKwZKEqQbS6 Unsharp shots: 5132 I did see some sharpness variation between more shots but nothing too bad.

The EF 50 1.8 STM lens test. First two are manual focus, rest are AF on tripod with about 1 second between shots. https://photos.app.goo.gl/Pn5o6YSPpSfc7qYv5 Unsharp shots are: 5089 5095 5101 5102 5103 5116 5117

Thanks, William Both my versions of the L lenses were Mark II as I recall. I'll eventually be getting them again. Just did a test with EF 50 1.8 STM and out of 52 images, 7 were not sharp. This time I used a tripod, manually focus the frist two shots and made sure the plane of focus was reasonably perpendicular to the wall. My earlier test of the EF 35 2 IS USM did not go well with about 3 sharp shots out of about 50 photos - also on a tripod, also had checked manually that the camera was perpendicular to the wall. I will retry that one later.

Thanks, William, for your thorough thoughts on the matter. I did see the focal plane issues as you described but the thing is that the centre AF point is not in focus. I guess I would have to use a tripod to make sure I did not move ever so slightly. I haven't compared the numbers of in-focus shots compared to my 5D II - but then again I'm using different lenses, mostly, and I'm out of practice using AF compared to back then so that wouldn't count, really. Mostly, with the 5D II, I used the EF 35L and 85L and their AF accuracy were both excellent and easy to use - easier than for instance the EF 85 1.8 USM in most real life circumstances - that is how I remember it, anyway. I will do an AF focus test later today with my tripod and the EF 35mm 2.0 IS USM and share my findings. Thanks again.

I just did another test, this time with my EF 80 1.8 USM and all 20 shots from about 3 feet were in focus and only 1 out of 9 distance shots were not sharp. I really can't explain it. I've spent hours doing these tests and then suddenly a lens is almost perfect. I see some parts of the images 4841 and 4843 are sharp but the center is not. Maybe something is off with this lens or maybe the camera was not completely perpendicular to the wall - I don't know. In real life situations using mostly the 70-200 and the 35mm (the lenses I have used the most) I do have more misfocuses than I would like. Maybe some lens and camera combinations work less well together - this would make sense for my Sigma lens but not the Canon lenses (as mentioned earlier, I've tested all lenses for microadjustments but that has not fixed the problems). Any suggestions about what to try out will be very much appreciated.

Answer to questions: Did you get Auto Focus Confirmation for every shot? Yes. What was the distance from wall to camera? About 1 meter. I have tried everything from close-ups to far away. Most shots have been about 1 or 3 feet from wall. What AF point was used? Center AF only. What images are not in sharp focus? (use the numbers please) 4841 and 4843

That is, it the AF square lights up for a moment and then goes away again. I tried it again coupling the AF to the shutter button, testing with 3 lenses, EF 50 1.8 STM, EF 70-200 2.9 IS II and EF 35 2.0 IS - all wide open. The 50mm had about 20% out of focus while the 35mm and 70-200 had about 10-15%. Anything else i can try to do? Thanks!

Sorry, yes, I did get AF confirmation for every shot.

I'm using the AF-ON button to focus so I'll try to change that as well so that I focus using the shutter button.

The red autofocus square is always on. I set it this way in the camera. I could try and change it and see if it makes a difference. C FnIII is now set to ON (when focus achieved).

Thanks! I used AF - One Shot! Handheld, fast shutter, lots of light, standing still. I don't remember having this kind of problems with my 5DII but that was some years back before it got stolen from my car and I never bother testing it - it just worked. Do you have any idea about what it will cost to get fixed or if it is even feasable?

Can someone please tell me what focusing accuracy I should expect from an EOS 1ds III on still subjects using single focus AF? How many shots should I expect will miss focus. It is an old camera and maybe the AF become less accurate over time.

My trusty EOS 5D II was stolen a few years back and so I recently bought a used 1Ds III - a great camera except the AF seems to be less reliable: I took some shots of our brick wall to demonstrate and, as is typical for this kind of shot, 2 out of 8 are not sharp at 100% magnification (see attached photos). I would say that about 20% of my shots of still subjects are not in focus and I don't recall having this kind of problem with my 5D. I have microadjusted the AF but the problem is inconsistency in both directions so this does not help. Using live view resolves the problem so the problem is definitely with the AF, not the lens. Is this to be expected and does anyone have any idea if this kind of problem is fixable and at what cost? Thanks.