5D mark iii focus issue

[niklashm]

I recently upgraded to full frame and got myself a 5D iii. When I shoot in landscape mode the auto focus works great, but once I tilt the camera into portrait mode the AF starts to struggle. When there is low contrast it is unable to focus properly. But when in landscape mode I can get the same spot perfectly in focus in a split second. Note that this only happens when using the 61 point Auto selection, the other AF modes works perfectly fine even when the camera is tilted.

What have I missed here?

 

[EIngerson]

When you are in portrait orientation are you using a cross type focus point?

 

[niklashm]

When you are in portrait orientation are you using a cross type focus point?

The focus points I use in landscape are not changed when I tilt the camera, if I understood your question correctly.

 

[KmH]

Cross type focus point can detect edge contrast both horizontally and vertically.

Regular focus point can only do one other the other, horizontal, or vertical, but not both.

Here are some details about the AF module in your 5D MK III -

[]AF Points
61-point (up to 41 cross-type points)

* One to five cross-type AF points at f/2.8
10 to 20 cross-type AF points at f/4
15 to 21 cross-type AF points at f/5.6.
(The number of cross-type AF points will differ depending on the lens.)

Canon does some really strange things.

 

[TCampbell]

When you use auto-selection mode you can't pick the point. The 5D III has 63 points, 41 are cross type (e.g. "+") and work at f/4 or lower and 5 are "dual diagonal" (e.g. "X") type points. But you can't pick the points it uses in the auto-select mode.

I have a 5D III, but I haven't had any focusing issues. I do have the issue where in auto-select mode it doesn't want to pick the object that I want it to pick, but that's to be expected. The Canon AF system always picks the nearest object available where it can achieve a focus lock. It's better to kick the camera out of auto-select mode when this happens.

 

[kathyt]

Here is a very good run through on some of the menu options. Look at the 14th one down on this list and see which one your camera is set at.
Canon EOS 5D Mark III AF and Custom Function Settings

 

[niklashm]

AF points are the same for both vertical and horizontal. I've adjusted most of the menu options without any luck.

When I try to focus at a low contrast area I rarely manage to get it in focus at all, when pointed at a high contrast area it also struggles, and gets in focus first after several seconds. All this when in portrait mode, landscape mode is fast and accurate at the very same spots. I find it weird that it should be such a difference, and that it can't use any focus points once I tilt it above 45 degrees (thats the limit I found).

 

[kathyt]

AF points are the same for both vertical and horizontal. I've adjusted most of the menu options without any luck.

When I try to focus at a low contrast area I rarely manage to get it in focus at all, when pointed at a high contrast area it also struggles, and gets in focus first after several seconds. All this when in portrait mode, landscape mode is fast and accurate at the very same spots. I find it weird that it should be such a difference, and that it can't use any focus points once I tilt it above 45 degrees (thats the limit I found).

That is strange. I would call Canon. Have you tried multiple lenses to see if you have the same issues?

 

[niklashm]

That is strange. I would call Canon. Have you tried multiple lenses to see if you have the same issues?

I've tried with three different lenses and the same problem occurred with all of them. I also tested them on my 550D, and managed to focus at the same spot without any problems. So the problem is most likely in the 5D iii. I guess I'll have to contact Canon and see if they have a solution.

Thanks for all the replies though, it's really appreciated!

 

[EIngerson]

Sorry to hear that niklashm. I hope you resolve it. I'll be keeping track incase mine does that.