5D3: AFMA variations between different AF points

Canon EF 24-105mm f/4L IS USM @ 105mm and f/4
5D3 #1
Double cross AF point vs outer AF point

Canon EF 24-105mm f/4L IS USM @ 105mm and f/4
5D3 #2
Double cross AF point vs outer AF point

Canon EF 70-200mm f/4L IS USM @ 200mm and f/4
5D3 #1
Double cross AF point vs outer AF point

Canon EF 70-200mm f/4L IS USM @ 200mm and f/4
5D3 #2
Double cross AF point vs outer AF point

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Paul, that pretty much is exactly what I'm seeing. After testing my 40 STM which was horrible w/ the corner points, I am sending my 5D3 back. Honestly if I can't get a body that performs reasonably with side points - why bother with 5D3 at all? I still have a nice 5D2 w/ a matte screen that I was meaning to sell. Center focus point works great on it, and my manual focus hit rate is better for off center shooting than my current 5D3.

I can post an update when the replacement body is here. I'll test it briefly with 40 STM.

Happy to hear that it may be the camera, and not the lens. I feel vindicated now.

This mirrors my experience exactly, especially with the 50L. I was experiencing this early on in my 5D3 ownership, and since my 70-200 and 24L weren't exhibiting the issue, I thought my 50L was broken. Sent it in and blew $2xx on calibration, and the lens came back exactly the same.

With the field curvature and now this phenomenon, the outer points are a dicey proposition.

nicksan wrote in post #15207373
This is pretty consistent with my experience [Snip] As I mentioned, it's particularly noticeable on my 50L but I find it actually does yield better results in AI Servo mode for whatever reason.

[Snip]

I just live with it, but would be interested to hear about any resolution if any of you send it in for calibration.

mco_970 wrote in post #15209427
Paul, that pretty much is exactly what I'm seeing. After testing my 40 STM which was horrible w/ the corner points, I am sending my 5D3 back. Honestly if I can't get a body that performs reasonably with side points - why bother with 5D3 at all? I still have a nice 5D2 w/ a matte screen that I was meaning to sell. Center focus point works great on it, and my manual focus hit rate is better for off center shooting than my current 5D3.

I can post an update when the replacement body is here. I'll test it briefly with 40 STM.

Michelle, do you mean you're going to do an exchange? Also, during my tests, I found that defocusing before the shot yields a better hit rate. When I shoot, I usually "pump" the focus 2-3 times before I actually take the shot, either because I'm not ready or because I'm setting myself up for the shot. Pumping the AF decreases the hit rate unfortunately. I guess since the focus is basically there already, AF'ing repeatedly in the same spot confuses the system, I don't know.

Yep, I am doing an exchange. Replacement body should be here tomorrow. I need to move over the GGS screen cover, so I will have two bodies for a day or so until the faulty one goes back. Really hoping the second one is better - (please please please!).

re: pumping the focus (hah, I wrote pimping the first time ) - you would expect in one shot mode it should not change to 'out of focus' if it is already 'in focus', no??

I am going to have to test that. Of course outer focus points will never be as good as central points, but is it better technique to use one of the edge center points and then recompose, or will there be better results by using the inferior edge focus points. Also this should be checked with how much light there is, maybe this is a problem only in poor light where non cross point focus sensors have a harder time correctly focusing.

To be honest, if anything, I feel the AF on the 5 DIII is fantastic ... but then again that was coming from a 5 DII. I have been using the moving of the focus dot around instead of center focus and recompose and focus has been excellent. This certainly needs checking out by experimenting with static objects in different lighting conditions and different lenses. It is possible that this is simply exposing the limitations of the AF ... so maybe using the outer center focus points and recompose will yield better results.

I just did a quick test. Contrasty target about 6 feet away, 200mm on 70-200 F2.8 IS II.
I tried all the focus points far left to far right. Used same spot on target. They all looked essentially the same on back of camera at max magnification.

I saw the comment about pumping, which I tend to do, so I racked focus out between shots and just pressed the shutter release, no pre-focus.

Earlier today I ran the lens through the FoCal routine and got both wide angle and tele settings within a point of each other -- plus 2 and 4.

I think I'll the other body tomorrow to see if there is any difference.

MatthewK wrote in post #15210036
Happy to hear that it may be the camera, and not the lens. I feel vindicated now.

This mirrors my experience exactly, especially with the 50L. I was experiencing this early on in my 5D3 ownership, and since my 70-200 and 24L weren't exhibiting the issue, I thought my 50L was broken. Sent it in and blew $2xx on calibration, and the lens came back exactly the same.

With the field curvature and now this phenomenon, the outer points are a dicey proposition.

I am sorry. I had my 50/1.4 boxed up and ready to send in for calibration because it was 'acting weird' on the 5D3 - my laziness actually payed off for once.

mco_970 wrote in post #15215268
I am sorry. I had my 50/1.4 boxed up and ready to send in for calibration because it was 'acting weird' on the 5D3 - my laziness actually payed off for once.

Hi Michelle, any updates on your new 5D3 body?

Yup.

Good on the center, good on the right.

Whatta ya think about the left side point? FoCal backs this up with the 35L and 40STM. I will try my 100L for giggles, but this is looking terrible. Actually this one seems worse on the left side than my other one was on the right side.

To add info, this is a cross type point on the left, the one in the middle of the vertical column so not even a far corner point.

This is just horrible for such an expensive camera. I can't believe it.

ETA: Gonna take a deep breath and check again with 100L. Maybe I'm seeing field curvature or something. Let's try it with a different lens in the telephoto range.