5D3 one shot AF

[jaayres20]

I would like to say first off I love the 5D3 AF and think it is very good.  It is very accurate and has allowed me do do things I couldn't have dreamed about with my 5D2.  However, there is one tiny issue that kind of bugs me and I was curious if anyone else has experienced this.  I have two 5D3s and they both do this.  With one shot AF in dim-dark situations it seems like it will focus quickly at first and then hunt a little before it finally gives me the red light to shoot.  During a reception last night I finally just switched over to AI servo and it was fast as lightning in pretty dim light.  Accuracy was really good as well.  I went into the menu and adjusted the setting that allows the camera to take the picture before "focus" is achieved in one shot mode and I liked it better.  It is like the camera achieves focus almost instantly but the red light has a small delay.  In a brief test I took several shots after focus but before the red light and found that almost all of the time the camera focuses just fine initially and doesn't benefit from the additional hunting before it shows red.  I hope that makes since.  Anyone else have a similar experience.

[PhilDrinkwater]

I don't have mine yet, but I have rented one and see the hunting. I think they made the "in focus" a little *too* accurate. I hope that's something they can change.

I'm going to be testing the setting you found. If it works for evening receptions, I'll be there. Realistically I can't wait around too long for focus, as you say...

[jaayres20]

I can't find anything else but let me know if you figure out any other adjustments that help.

[awinphoto]

One of the review videos people has posted on canonrumors putting the 5d3 and D800 side by side said the comparing the two the 5d3 had faster overall focus whereas the D800 had almost a faster initial focus but then did fine tuning after the initial focus which slowed down the AF process...  The only caveat was that in low low light the d800 had a focus assist light and pop up to help focusing whereas the 5d3 has no such AF lamp or flash.  Have you tried if having a flash on the hotshoe but just using the assist beam and turning the flash itself off?  Maybe that could be an aid in this situation. 

[jaayres20]

Yes I even have the 600ex which is supposed to work well with the 5D3 AF.  When I am close enough it does help but not much.  A lot of times I am at a distance with my 70-200mm and the AF assist beam doesn't do much then.

[awinphoto]

Yes I even have the 600ex which is supposed to work well with the 5D3 AF.  When I am close enough it does help but not much.  A lot of times I am at a distance with my 70-200mm and the AF assist beam doesn't do much then.

Pretty tough situations... I suppose if Al Servo was fast and good in dim situations, that should be your go-to focus setting.  I myself used to be a one shot focus guy on my prior cameras but with the 7D onwards I learned to love al servo, especially on moving subects, even models and kids who may in inadvertently moving a little at a time.  But that far away with little to no help for your AF system, your next best solution may be live view and manual focus or phase detect focus... 

[dswatson83]

You can adjust the accuracy of the focus system in the settings. You can adjust "first shot priority" and "second shot priority" to if you would like the camera to take the photo after focusing or to double check to ensure perfect focus before taking the shot. That may fix your issue but I do not have the mark III yet unfortunately

[te4o]

As dswatson says you can prioritise shooting or focusing. That does the job. I did set my DoF preview button to change SingleShot-AIservo for rapidly changing situations. I did register AF points in all three positions of the camera (Portrait, left right and landscape) and found that I need just to push buttons to jump AF from one end of the screen to the other or to the middle - it is very fast and metering follows well: eg in landscape I registered one AF point at 1/3 to the left, pushed the active point to 1/3 to the right via multicontroller and if I need middle than just depress the multicontroller straight down. So, push AF-ON goes the the left, and depressing the multicontroller juggles between middle and far right or where I left it before. I quite like this shortcut instead of hitting the multicontroller all the time around.