On a Canon 5D MkIII, is there anyway to see the autofocus lock boxes on screen while manually focusing (showing the areas the camera detects as in focus)? This might just be an insane product of my imagination but I have a 35mm lens and this would be helpful just for making sure my focus is more perfect the first time around, I know all the tech for this exists, just don't know if Canon actually connected these features together somehow.



There are many settings on the Canon 5D mark III that affect what you see and when you see it in the viewfinder. The camera does have the ability to indicate when focus is achieved over a certain point during manual focus, but only if all of the correct settings that affect the display are selected.

  • Start in the menu with AF tab 3 USM lens electronic MF and set it to On.
  • Be sure that AF tab 5 AF point display during focus is not set to disable. I use Selected (constant).
  • Set AF tab 5 VF display illumination to On.
  • Rather than selecting all of the 61 focus points, select only a few or even one using Zone AF, AF point expansion, Single-point AF, or Single-point Spot AF. If you do select all 61 points, focus confirmation will only occur for the center AF point

When I have the above settings selected and manually focus my EF 70-200mm f/2.8 L IS II attached to my 5D mark III while holding a shutter half press (or the AF-ON button), the focus display blinks red and the focus confirmation light blinks green very briefly when focus is achieved. If I move the focus ring too fast, the camera usually doesn't catch it and never flashes as I move past focus for the selected points in the viewfinder. But when I move the focus ring more slowly in the area near focus, it will very briefly blink when it detects the subject behind my selected focus point(s) is in-focus.

The Canon EOS 7D focus system is very similar in terms of set-up to the EOS 5D mark III.

For an even more detailed answer regarding what will show in the viewfinder and when it will show, please see this answer to What settings affect how the focus points are displayed for my 7D?

  • 1
    This is exactly what I was looking for. Not foolproof but I'm happy I can get a feel for it and it worked well enough at f1.4 to make me feel a little more confident in MF mode. Thanks so much! Mar 30 '15 at 0:51

There are two ways I see to describe what you are asking for.

One would be to simply turn on all focus points in the AF Menu, manually focus, then press on half-way on the shutter release and any points that overlap the focus points and are in focus will light up. This is the same as the 7D.

What I think you are ultimately looking for is commonly referred to as Focus Peaking. The Canon 5D MkIII does not natively have this feature.

What you could do to get this feature is install the Magic Lantern firmware. You may want to check out the Magic Lantern tag on this website for more info too.

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