AF Point keeps jumping back to the centre

[Ludo]

I really hope someone can help me.  I manually select an AF point, use the back-button focus, and as soon as i press the shutter release, it jumps back to the centre point.  I'm tearing my hair out as I need to use my camera tomorrow and I don't know what I've done to it.  Have even done a full reset but it didn't change anything.

[Waddizzle]

What camera are you using?  Are you maintaining the BBF button until after the shutter releases.  The behavior that you describe is consistent with some AF focusing options in select cameras.

[Ludo]

I'm using the 5D MKiii.  And I'm sure it's an option I've chosen but no matter what I do it doesn't change it.  I've even done both the resets suggested.

[RobertTheFat]

---

Ludo wrote:

I'm using the 5D MKiii.  And I'm sure it's an option I've chosen but no matter what I do it doesn't change it.  I've even done both the resets suggested.

---

There are numerous autofocus options and several ways to program the back button. I don't know how long you've had your 5D3, but if, like many of us, you're still at the "looking things up" stage, you should make sure that you're seeing the unabridged version of the instruction manual. The printed version may not be it, so you may have to look on the CD that came with the camera or on the Canon Web site. 

[TCampbell]

Are you in AI Servo mode with the full 61-pt AF area chosen?

In this mode you get to pick the initial AF point, but the camera will try to "follow" your subject (part of Canon's iTR feature.  iTR is "intelligent Tracking & Recognition").  The first page of the AF settings on your camera menu determine "how" the iTR feature will follow your subject.

There's a 47 page book that explains the AF system on this camera.  You can download it here:  http://cpn.canon-europe.com/files/product/cameras/eos_5d_mark_iii/AF_guide_EOS5D_MarkIII_eng_January...

Anyway... when you use the full 61-pt AF area with AI Servo mode, you get to set your "initial" AF point and then the camera will attempt to follow that subject (based on the algorithm you chose) as best as possible.  BUT... if you release the focus button (either release the back button or release the shutter button) then it reverts back to the initial point again.  

If you tap (don't hold) the AF area selection button (upper right corner button on the back) and also make sure you do not press the back button or shutter button, then you can use the 8-way navigator to move the "initial" point and pick a new initial point.  (you can also configure the camera so that the selection wheels pick the point instead of the 8-way navigator).

There are a number of Canon videos and guidebooks on using the AF system with the 5D III.  It's a very advanced focus system which is extremely powerful once you get used to it, but can seem confusing at first. 

[jrhoffman75]

For general guidance, there are two resets: reset camera settings and clear all custom settings.. If you don't do both unexpected behaviors may not be cleared.

[Waddizzle]

---

@Ludo wrote:

I really hope someone can help me.  I manually select an AF point, use the back-button focus, and as soon as i press the shutter release, it jumps back to the centre point.  I'm tearing my hair out as I need to use my camera tomorrow and I don't know what I've done to it.  Have even done a full reset but it didn't change anything.

---

When you set up the back button focus, did you remove AF from the shutter button?  In order to properly set up BBR, you must reprogram both the shutter and the <AF-ON> buttons.

[JennyWPhoto · Accepted solution]

I had this same problem after my 5D Mark iii was reset.  This fixed the problem for me!

Go to the Menu

Go to the second Custom Function panel (orange camera icon)

Select Custom Controls

Select the button you have selected to be your BBF button

This should be Metering and AF I believe

**Push info button for detail set

**Make sure "Manually selected AF Point" is highlighted.

The other option "Registerd AF Point" tells the camera to use the center point rather than the one you manual choose.

[Ludo]

JennyWPhoto - You are a star!!!!  This worked perfectly - thank you so very, very much!!!!

[Ludo]

Hey Jenny, do you maybe know why my shutter speed alwasy sounds so slow, irrespective of what setting I have it on?