Auto focus doesn't work on bird surrounded by foliage

[rfermat]

I have a Canon EOS 5D Mark III, purchased in late 2016.  I've taken at least 10000 photos with it.  I use either the EF 100-400 IS II or the 70-300 image stabilizer lens.  In either case, when I am photographing a bird that is perched on a branch and has background foliage, AF usually doesn't work.  I have lost at least 70% of the oppotunities for such photos, as eventually the bird flies off.  The %$^&#$ camera insists on focusing on the background or foreground.   These are situations where I am reasonably close to the bird, so that it opccupies maybe 1/12 or 1/16th of the image.

This is beyond frustrating.  I have experimented with many different AF settings and nothing seems to do any good.  

Anyone else have this problem?

[MikeSowsun]

Have you tried manually selecting "Single-point Spot AF"?

It is the best solution to your problem. 

[rfermat]

Thanks.  That's one of the things I tried.  Didn't seem to do much good.

[wq9nsc]

As Mike suggested you need to use single point AF and I would set to single shot instead of servo.  I would also check to see if you need to calibrate the lens to your camera to ensure that it isn't front or back focusing: 

https://www.learn.usa.canon.com/app/pdfs/articles/AF_MicroAdjustGuide_desktop.pdf

Rodger

[rfermat]

Thanks for that link.  I'll look at it.  Also, I leave it on AI Servo all the time, as that was the advice I saw on various web pages.  I'll try going back to single shot.

[wq9nsc]

AI servo works very well and I use it all of the time for sports shooting but depending upon the setup if you shift the camera slightly with a static scene like a perched bird it may quickly shift focus to something else in the scene.  Go with single shot holding the button halfway down to lock focus as you smoothly depress the shutter release all of the way.

At times a tripod will really help with this situation.

Rodger

[RobertTheFat]

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@rfermat wrote:

Thanks for that link.  I'll look at it.  Also, I leave it on AI Servo all the time, as that was the advice I saw on various web pages.  I'll try going back to single shot.

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The purpose of AI Servo is to pick up and follow moving objects. If the bird is just sitting there waiting for you to finish taking his picture, you want Single Shot.

[rfermat]

Right.  But wih bird photography you never know when you will want to shoot a flying bird too.

[ebiggs1]

"This is beyond frustrating.  I have experimented with many different AF settings and nothing seems to do any good."

I am sure it is but let's go at it more deliberately.  First stop trying so many things all at once.  Change just one thing at a time.

AMA is the last thing to try.  Set that back to zero right now.  Set AI-Servo off and make it more one of the later things.  Also it is a good idea to just do a total reset of the 5D Mk III camera.  Get it back to factory settings.  Square one if you will.

Now select just the center AF point.  Turn all the others off.  Set to One Shot.  Select a fairly high ISO 800 to 1600.  I prefer Av.  If you have the 100-400mm lens, set the Av to f8.  If you have this lens, the black one, EF 70-300mm f/4-5.6 IS USM Lens, I would stop using it at all.  It is not worthy of a 5D3, IMHO.  Set the WB to Auto.  Always use Raw file format and make use of a good post editor.  <-- very important!

Now don't change from these settings until they no longer work.  But,  but, there is always a 'but' isn't there?

The most important thing you can do is get closer.  Get closer to your subject.   Sometimes this is very difficult but if it were easy everybody would be doing it. Right?  1/12 to 1/16,  is way too small for reliable accurate AF with any lens. Any camera!   It helps to learn the habits of the animal you are shooting.  If you know where they feed or where they roost, water sources for instance.

Lastly it is possible to pick a situation that the 5D Mk III just can't handle.  All cameras, photography, have their limits.  There is just so much that can be built in to automate it.  However, even then we have a possible solution, MF or manual focus.  BTW, it is sometimes a good idea to pre-focus the lens before you try the shot.  You know, you estimate, the bird is 20 feet away.  Set the lens to 20 feet first.  Then try AF on it.

Let me know if this helps.

[MikeSowsun]

You haven't made it clear if you have tried Single-point SPOT AF.

Single-point SPOT AF covers an even smaller area than the center AF point and will make it easier to isolate the subject form the surrounding foliage. 

Here is a detailed explanation of the difference between Single-point AF and Single-point SPOT AF: An inside look at Spot AF

• Standard, Single-point AF provides coverage that extends BEYOND the borders of the AF point you see in the viewfinder
• Spot AF actually covers an area virtually the same size as the primary, single AF point you see in the viewfinder… it definitely extends beyond the inner “box” you see when Spot AF is indicated on your focus screen

Summary

While it’s not necessarily the go-to AF Area setting for every situation, Spot AF gives the experienced DSLR shooter a means to work even more carefully with his or her AF and place the sharpest focus even more precisely on the subject where it’s wanted. If you own a camera with this feature, it’s worth experimenting with and learning where it can be of benefit to you. Simply keeping in mind the actual area covered (see the graphics, above, in this article) goes a long way toward truly maximizing Spot AF’s potential. And, equally important, is awareness of where the other AF Area options display their benefits.