topic Re: Auto focus doesn't work on bird surrounded by foliage in EOS DSLR & Mirrorless Cameras

Auto focus doesn't work on bird surrounded by foliage

rfermat — Tue, 10 Jul 2018 19:36:25 GMT

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?

Re: Auto focus doesn't work on bird surrounded by foliage

MikeSowsun — Wed, 11 Jul 2018 15:18:32 GMT

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

It is the best solution to your problem.

Re: Auto focus doesn't work on bird surrounded by foliage

wq9nsc — Wed, 11 Jul 2018 13:10:43 GMT

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

Re: Auto focus doesn't work on bird surrounded by foliage

rfermat — Wed, 11 Jul 2018 13:24:02 GMT

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

Re: Auto focus doesn't work on bird surrounded by foliage

rfermat — Wed, 11 Jul 2018 13:29:58 GMT

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.

Re: Auto focus doesn't work on bird surrounded by foliage

wq9nsc — Wed, 11 Jul 2018 13:38:31 GMT

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

Re: Auto focus doesn't work on bird surrounded by foliage

RobertTheFat — Wed, 11 Jul 2018 14:01:36 GMT

@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.

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.

Re: Auto focus doesn't work on bird surrounded by foliage

rfermat — Wed, 11 Jul 2018 14:59:53 GMT

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

Re: Auto focus doesn't work on bird surrounded by foliage

ebiggs1 — Wed, 11 Jul 2018 15:08:09 GMT

"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.

Re: Auto focus doesn't work on bird surrounded by foliage

ebiggs1 — Wed, 11 Jul 2018 15:14:06 GMT

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.

Re: Auto focus doesn't work on bird surrounded by foliage

MikeSowsun — Wed, 11 Jul 2018 15:32:00 GMT

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.

Re: Auto focus doesn't work on bird surrounded by foliage

ebiggs1 — Wed, 11 Jul 2018 16:02:21 GMT

Keep in mind Single-point SPOT AF is not an option if you are in Auto mode. You shouldn't be any way but just to be clear.

Av is the best choice.

Re: Auto focus doesn't work on bird surrounded by foliage

rfermat — Wed, 11 Jul 2018 17:01:48 GMT

Thank you. I did not know there is a difference betwen Single-point AF and Single-point SPOT AF. I don't recall seeing thay fact anywhere before.

Also, I am astonished to see your blue and red rectangles. I assumed single spot meant -- single spot. Duh. Evidently not.

Re: Auto focus doesn't work on bird surrounded by foliage

ebiggs1 — Wed, 11 Jul 2018 17:23:07 GMT

"Evidently not."

No it does mean just a single more tiny single point. You will not see anything additional in the viewfinder just a smaller square. The colored example just indicates coverage you can expect.

I would not use it as a first option. Let's get the basic settings a good try first. When things don't go as expected it's always best to start off at the beginning. The walk before you run thingy.

Re: Auto focus doesn't work on bird surrounded by foliage

TCampbell — Wed, 11 Jul 2018 23:42:12 GMT

The 5D III (and IV, and 1D X, 1D X II, 7D II, etc.) are all very "technical" cameras. They are very powerful... but they have loads of options that other cameras don't have.

You really want to take the time to go through the manual and learn the features.

Also, download and read Canon's 47 page PDF guide on the 5D III auto-focus system (this entire 47 page document is dedicated to JUST the focus system on your camera ... the number of pages alone should give you some idea that this camera has a LOT of options when it comes to focus.)

http://cpn.canon-europe.com/files/product/cameras/eos_5d_mark_iii/AF_guide_EOS5D_MarkIII_eng_January2013.pdf

"Spot AF" is not the same as "Single Point AF". Spot AF reduces the AF point to the smallest size possible to avoid possibility that another object will interfere with your subject and confuse focus. But also... when you are in AI Servo mode, all the "case" settings (you'll read about those in the document) come into play. You can tune the behavior of the camera as to whether it should ignore obstacles that momentarily block your subject ... or if should immediately snap the focus to that new subject.

A downside of "Spot AF" is that since the point is much smaller, it needs to be something wtih good contrast (to help the camera lock focus). "Single Point AF" has a more generous area so that's more opportunity to find contrast to lock focus. There's also "AF Point Expansion" that uses four additional AF points (above/below/left & right of your chosen AF ... these points "extend" the range of the single AF point. There's also an AF Point Expansion that uses all 8 surrounding points (again... same behavior. It wants to use the center but borrows the other points to "expand" the area in an effort to increase the area to search for good contrast.) The risk is... as you expand the area it can search for good contrast... it might find good contrast on a tree branch or leaf and NOT on your subject.)

If you have a fast moving subject free of distracting obstacles, the camera can often work better (focus faster) if you give it a larger area. Basically use more when you can. When you realize there are competing obstacles... reduce the area so the camera HAS to use the tiny little spot you picked out to lock focus.

Re: Auto focus doesn't work on bird surrounded by foliage

rfermat — Thu, 12 Jul 2018 14:54:55 GMT

Thanks for all the replies.

A perched bird is basically an ellipse for the body, an ellipse for the head, and a rectangular shape for a tail. There may be a branch interesecting one of these. Nonetheless, I don't see why software can't be written to search for a bird near the center of the field of view. I say this as a mathematician and computer programmer.

This would establish a "perched bird mode". It's more complicated for a flying bird, but I've not had trouble photographing them. Usually there is no competing foliage.

Re: Auto focus doesn't work on bird surrounded by foliage

ebiggs1 — Thu, 12 Jul 2018 15:31:46 GMT

Remember camera sensors only see luminosity. They can not distinguish a limb from a bird since it is just lighter or darker.

Re: Auto focus doesn't work on bird surrounded by foliage

kvbarkley — Thu, 12 Jul 2018 15:46:15 GMT

That might work in live view, but through the view finder you only have at most 60 widely separated pixels.

And you might want a perched-bird focus mode, but I want a bee focus mode.

How many modes should canon add?

Re: Auto focus doesn't work on bird surrounded by foliage

coachboz68 — Thu, 12 Jul 2018 16:10:19 GMT

<<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?

Re: Auto focus doesn't work on bird surrounded by foliage

coachboz68 — Thu, 12 Jul 2018 16:23:25 GMT

@rfermat wrote:
Nonetheless, I don't see why software can't be written to search for a bird near the center of the field of view. I say this as a mathematician and computer programmer.

Sorry if this is a bit of a diversion from topic... but I am in tech as well, so your comment caught my eye. Google is doing quite a lot with its AI platform wrt photography. In this [1] case, they worked on using AI to sift through "street view" images and basically work out which clips would make "good" photographs. They've also been doing well in competitions against human photographers where people "vote" on images. And here [2] is an example where they are doing more with short video clips that are determined worthy of capture with their AI. I suspect that phones will be the faster adopters of AI technology for photography and professional-grade cameras will lag a bit due to the use cases being somewhat different.

[1] https://petapixel.com/2017/07/14/google-uses-ai-create-professional-photos-street-view-shots/

[2] https://ai.googleblog.com/2018/05/automatic-photography-with-google-clips.html