sony a9 and 400/600 seem to be doing just fine. it might be with the current technology canon has
markd61 wrote:
I remember Canon reps talking about why a 1D series mirrorless was a bad idea saying that long lenses had a difficult time focusing with mirrorless.
This was their rationalization for saying ML was for amateur and enthusiast cameras.
I have zero idea if this was true or just smoke they were blowing to rationalize their late entry into MILC cameras.
Oh crap. I finally got home from vacation to get to my AFMA target. Mine is doing the same thing. At 200 f2.8 MFD it is front focusing by about half a centimeter. If I back up to about 6 feet, it is off by the same margin.
At 70mm MFD and about 6 ft back it is dead on.
At 177mm f/2.8 MFD the problem is still there
At 135mm f/2.8 MFD the error has shrunk to about 2-3mm.
At 100mm f/2.8 MFD the problem appears to be gone.
I can’t post photos here for some reason, sorry. This is all based on 8-10 shots per setting of a focus target, which has a ruler built in. The results are perfectly consistent- every frame at the same setting and distance matches the next.
Thank you for brining this to my attention. I’m going to be contacting Canon about this tomorrow. Please let us know what you hear back from them.
jkochuni wrote:
Could you take a picture at 200mm MFD using Eye AF, and report back with a picture?
Thanks for running those tests. It’s scheduled to arrive Friday, so I will keep everyone updated. I bought the lens to use mainly at f/2.8 so this is a huge problem for me. I will have to return it if Canon is unable to fix this. So far Canon has yet to post my review even though I received an email saying it was approved. Makes me wondering if they are trying to keep this quiet until they get a fix.
jdavidse1901 wrote:
Oh crap. I finally got home from vacation to get to my AFMA target. Mine is doing the same thing. At 200 f2.8 MFD it is front focusing by about half a centimeter. If I back up to about 6 feet, it is off by the same margin.
At 70mm MFD and about 6 ft back it is dead on.
At 177mm f/2.8 MFD the problem is still there
At 135mm f/2.8 MFD the error has shrunk to about 2-3mm.
At 100mm f/2.8 MFD the problem appears to be gone.
I can’t post photos here for some reason, sorry. This is all based on 8-10 shots per setting of a focus target, which has a ruler built in. The results are perfectly consistent- every frame at the same setting and distance matches the next.
Thank you for brining this to my attention. I’m going to be contacting Canon about this tomorrow. Please let us know what you hear back from them.
Two points that seem not to be coming though clearly in this thread:
First, it appears that the RF 70-200 lens is not at fault. There has been limited testing with other lenses, but they seem to demonstrate the same problem. This suggests the problem is with the autofocus system at close focus distance, long focal length, and wide aperture. Probably the issue has become more apparent with the release of the RF 70-200 because it has a closer MFD.
Second, holding conditions constant, the auto-focus system consistently and rapidly reproduces the same error. If Canon's DPAF were inherently flawed the error would more likely be randomly distributed throughout some range and/or cause hunting. To the contrary, the focus system is quite confident and quick to focus, even if at the incorrect distance. Given it is able to consistently produce the same result, it seems likely this can be fixed by tweaking the autofocus firmware.
The claim that Canon's "DPAF in its current incarnation may be insufficient for wildlife and sports photography" seems particularly unsupported given that both of those use cases are usually at longer focus distances -- where we have not seen any evidence of focus misses.
Although this is how I interpret the evidence, there is one big thing that gives me doubt. How is it possible that Canon didn't find and fix this problem long before the RF 70-200 was released?
I have a 600mm III, and I have not seen any focus issues at MFD f/4 with and without a 1.4x teleconverter. I would think given the magnification it would be noticeable especially when focused on a subjects eye if the autofocus on the EOS R was off.
I am facing the question of whether return mine to the retailer or send it in for repair. I got my lens on Greentoe at a pretty sweet discount. I don’t think an exchange would do much good as this seems pretty widespread. There should be time to do both (send in for repair and then go for a refund if need be.)
jkochuni wrote:
Thanks for running those tests. It’s scheduled to arrive Friday, so I will keep everyone updated. I bought the lens to use mainly at f/2.8 so this is a huge problem for me. I will have to return it if Canon is unable to fix this. So far Canon has yet to post my review even though I received an email saying it was approved. Makes me wondering if they are trying to keep this quiet until they get a fix.
I wouldn’t bother with an exchange. So far we have not found an issue free lens and/or camera. I purchased mine from Kenmore Cameras, and they have been extremely helpful dealing with this issue.
jdavidse1901 wrote:
Did you buy yours from Canon?
I am facing the question of whether return mine to the retailer or send it in for repair. I got my lens on Greentoe at a pretty sweet discount. I don’t think an exchange would do much good as this seems pretty widespread. There should be time to do both (send in for repair and then go for a refund if need be.)
jkochuni wrote:
I wouldn’t bother with an exchange. So far we have not found an issue free lens and/or camera. I purchased mine from Kenmore Cameras, and they have been extremely helpful dealing with this issue.
Ok I'm sending mine in to Canon tomorrow. I was going to wait to hear what happens with yours, but what's the point in that? Either they fix it or they don't, and I need to get it back inside of my return window.
I've posted a thread over at Dpreview with photos of my test. I redid the test with better lighting, a tripod and a 2 second delay. It's definitely missing by about 3mm at 200.
Jesse Evans wrote:
Thank you for doing that! Would you mind posting those pictures on your dpreview thread or on here for posterity / proper information?
Looks like this lens is following the path of EF 600mmIII. It took 3 firmware updates for that lens to work as it should. And some 7 months of answers like:"the lens is within parameters".
Uarctos wrote:
Looks like this lens is following the path of EF 600mmIII. It took 3 firmware updates for that lens to work as it should. And some 7 months of answers like:"the lens is within parameters".
I believe that since this is so repeatable, easily repeatable, Canon will resolve this issue quickly.
jkochuni wrote:
I posted a thread on the EOS R Facebook forum, and I had two individuals test their lens, and they say they are not experiencing any issues.
Did they post evidence? I also didn’t think I had the issue until I did the objective test.
