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?

[ebiggs1]

"I don't think it should be hard to add ellipses."

This is all a camera sensor sees...........

It doesn't see shapes of any kind.  Perhaps you can make a break through and improve how it works but this is all a camera sees right now.

[TCampbell]

You can develop a computer algorithm to look for shapes -- that aren't really AI or Machine Learning.  I used to work as a developer of CAD/CAM software and I recall developing a function that tried to guess what part of a geometric constuct you probably *meant* to select based on where you *actually* clicked with your stylus.  It may have seemed "smart" but in reality it was a fixed algorithm with no abilty to "learn".  So it wasn't really AI.

For true AI & Machine Learning, the system does have to be able to "learn".

Anyway... here's a good video series on the topic.  As you mentioned your into math, you may find an appreciation for what it is doing:

https://youtu.be/aircAruvnKk

That's just the first video in a series ... each one is around 20 minutes.  But after an hour or so you'll have a pretty good idea of what's going on.

[ebiggs1]

An accurate AF system that can distinguish between a small bird and twigs is most likely not going to happen soon enough to help either of us!

[coachboz68]

<<Select a fairly high ISO 800 to 1600.>>

ebiggs1.... Can you elaborate on this a little just for my own knowledge?  Does that ISO range somehow improve AF sensor capabilities?  

[ebiggs1]

"<<Select a fairly high ISO 800 to 1600.>>

ebiggs1.... Can you elaborate on this a little just for my own knowledge?  Does that ISO range somehow improve AF sensor capabilities?"

No it doesn't.

I don't remember the context of my reply as I didn't dig back through the replies but this is to help keep SS higher or faster if you will.  It has nothing to do with AF.  Camera sensors only see light and dark. All shades of gray. Black is on one side and white is on the other side of the scale.  This is the Raw data.   Color is figured out and added by the camera electronics and software.

[TCampbell]

---

@coachboz68 wrote:

<<Select a fairly high ISO 800 to 1600.>>

ebiggs1.... Can you elaborate on this a little just for my own knowledge?  Does that ISO range somehow improve AF sensor capabilities?  

---

ISO is a "gain" (amplification of the data) that the camera applies only after the exposure is completed (shutter is closed).    It does nothing to how the camera behaves prior to or during the shot.  The only exception is that if you use live-view, Canon performs "exposure simulation during liveview" meaning if you dial the ISO up & down while in "live view" mode, you'll notice the image getting brighter or darker.  But it's just a "simulation" being shown to you and doesn't accurately represent what the camera sees.

[ebiggs1]

rfermat,

This shot is not a keeper. Not one of my better efforts.   I found it in my discards for deleting but it does show the settings I suggested and getting closer does work.

"... it opccupies maybe 1/12 or 1/16th of the image."

Remember this is way to small for good AF perfromance.

[Waddizzle]

---

@rfermat wrote:

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?

---

I have saved a custom shooting mode for shooting a bird sitting on a branch, surrounded by other branches.  I have found using a monopod, or some other support, really helps.

I select just the center AF point.  Never bothered with Spot AF.  I use Single Shot focus mode.  I also use Back Button Focus, so that the lens does not try to refocus when I press the shutter.  The focus stays put until I refocus it again.   It usually takes me 2-3 attempts to nail the focus where I want it..

[Waddizzle]

[huskyC]

Nice shots. What are the gears you used and settings please ?