Focusing on the eye (1 Viewer)

YellowBudgie · Nov 28, 2007

Hello Everyone,

I was wondering about this the other day. I was curious why cameras can often get good focus when using a birds eye to auto focus on.

Is it the birds eye color in contrast with the birds eye ring, feathers, etc? Does the round shape of the eye help the camera to focus as well? Any other reasons?

Thanks,

Dana

gordon g · Nov 28, 2007

It's down to the photographer using the centre focus point from the focus point array, which is nearly always the most sensitive, to put the focal plain exactly where they where they want it, ie the eye. This is the most critical place in a portrait image to have sharp focus.
You're right that higher contrast objects make focusing easier for the sensor, but the choice of focal plane is basically operator-dependent.

YellowBudgie · Nov 28, 2007

gordon g said:
It's down to the photographer using the centre focus point from the focus point array, which is nearly always the most sensitive, to put the focal plain exactly where they where they want it, ie the eye. This is the most critical place in a portrait image to have sharp focus.
You're right that higher contrast objects make focusing easier for the sensor, but the choice of focal plane is basically operator-dependent.

Thanks Gordon,

In general I'm assuming a birds eye and what surrounds the eye presents the most variations of elements that are good for the camera's sensor to process and have the best chance at obtaining a good focus?

I always wondered what the elements were about the birds eye that made it such a good place to focus on. It does seem to be a detailed and varied area in a good amount of birds.

Thanks,

Dana

YellowBudgie · Nov 29, 2007

Hi Gordon,

I was playing around with the Canon 100-400mm indoors today. I setup one of those decoration birds made with chicken feathers, styrofoam, etc. Even though the area around the plastic eye was plain looking you could hear the lens re-focus once the AF point was on the eye getting a better focus.

I've noticed some birds tend to be predictable where a AF point could be used on the eye. When a birds head/body is moving do you normally take a few quick shots and then try for the birds eye in the AF point hoping for good timing where you get the AF point eye shot in AI Servo mode?

Thanks,

Dana

gordon g · Nov 30, 2007

With a moving target, I would use AI servo focus mode. That way the camera will monitor the subject's movement and (hopefully) correct the focus appropriately. You will need to move the camera to keep the focus point over the part you want to focus on.
Where you place the centre point also depends on the orientation of the bird relative to you. Side-on is easiest - just use the eye. At an angle, use the eye if you can see it well enough for the focus to lock on. If you cant get a good lock on the eye, try the base of the beak, it shouldnt be too much different too the eye.

a.dancy · Nov 30, 2007

Dana

The reason you focus on the eye has nothing to do with the enablement of autofucus. If you photograph manually you should still focus on the eye. This is because the person viewing the photograph is going to have his or her eye drawn to the bird's eye. The eye is the window of the soul. It is what gives life to the image and for that reason the eye should be sharp. Most people , probably use al-servo and keep clicking. I use Al-servo about 50% of the time, if that. I tend to try and predict movement and shoot accordingly( less time spent processing

)

gordon g · Nov 30, 2007

a.dancy said:
Dana

The reason you focus on the eye has nothing to do with the enablement of autofucus. If you photograph manually you should still focus on the eye. This is because the person viewing the photograph is going to have his or her eye drawn to the bird's eye. The eye is the window of the soul. It is what gives life to the image and for that reason the eye should be sharp. Most people , probably use al-servo and keep clicking. I use Al-servo about 50% of the time, if that. I tend to try and predict movement and shoot accordingly( less time spent processing )

That's a clearer way of saying what I tried to say in my first post. :t:

YellowBudgie · Nov 30, 2007

gordon g said:
With a moving target, I would use AI servo focus mode. That way the camera will monitor the subject's movement and (hopefully) correct the focus appropriately. You will need to move the camera to keep the focus point over the part you want to focus on.
Where you place the centre point also depends on the orientation of the bird relative to you. Side-on is easiest - just use the eye. At an angle, use the eye if you can see it well enough for the focus to lock on. If you cant get a good lock on the eye, try the base of the beak, it shouldnt be too much different too the eye.

Thanks Gordon!

YellowBudgie · Nov 30, 2007

a.dancy said:
Dana

The reason you focus on the eye has nothing to do with the enablement of autofucus. If you photograph manually you should still focus on the eye. This is because the person viewing the photograph is going to have his or her eye drawn to the bird's eye. The eye is the window of the soul. It is what gives life to the image and for that reason the eye should be sharp. Most people , probably use al-servo and keep clicking. I use Al-servo about 50% of the time, if that. I tend to try and predict movement and shoot accordingly( less time spent processing )

Thanks for clearing that up. I always though it was a better way to get good focus when the entire bird would be in the DOF range (sorry, don't know the technical way to word that).

With manual focus shots I would tend to look at the entire image and certain details like the feathers but never took in account the birds eye when in manual focus.

Thanks for that tip! I'll start to pay closer attention the the birds eye when using manual focus as well.

See ya,

Dana

joannec · Nov 30, 2007

a.dancy said:
Dana

The eye is the window of the soul. )

I like it..... in more ways than you probably meant!

bkrownd · Dec 1, 2007

The odd thing about this "focus on the eye" idea is that the autofocus spot is usually similar to or larger than the birds whole head, so you're probably focusing on the outline of the head more than anything else. I usually autofocus at the bird's feet, because the camera seems to prefer to autofocus on branches if given a chance, and at least you know the branch it's standing on is at the right distance. The branch is often a larger target than the bird, as well. Using the head end of the bird as the target often results in the autofocus snapping back and forth between the various levels of foliage along the line of sight. *sigh*

a.dancy · Dec 1, 2007

I (personally) would not advise focusing on a branch. Determining which part of the branch to focus on can be very difficult. If you are working close up with a shallow depth of field I imagine you will get more shots for the bin than keepers. If the bird is a long way off the DOF will increase so you will probably get most of the bird in focus anyway. Having said that I still would not go for the branch because your eye is then taken off the bird's eye and you will not know if you are going to get the highlight in the bird's eye which will make your picture altogether more please and engaging. You will also be loosing the feel for the birds most engaging poses.

By all means focus on the branch if you can predict that the bird is going to move to it. You will get quicker focus when it eventually hits the spot where you want it.

You can often get a good shot when focusing on the nape.

bkrownd · Dec 2, 2007

a.dancy said:
I still would not go for the branch because your eye is then taken off the bird's eye and you will not know if you are going to get the highlight in the bird's eye which will make your picture altogether more please and engaging. You will also be loosing the feel for the birds most engaging poses.

Usually it's a matter of getting what you can. Using the branch or foliage to quick focus increases your odds of getting an ID-able photo. The autofocus control on cameras isn't designed with photos of dark camoflaged little birds in the bowels of bushes and trees in mind, so you have to compromise with the camera. The branch, foliage and legs are a much better bet for quick focus than any part of the bird's dark little body. There's usually less than 2 seconds to get a photo before a bird moves, so first I go for the sure thing and make sure I've got an ID shot or three to work with. When I have that in hand I might start thinking about highlights, "engaging poses" and whatnot.

If you try for the head side of the bird right away you might get lucky...or often your focus will just zoom in/out to surrounding foliage, bokeh or la-la land. Once it goes hunting you have to fight it back to the right range and your bird is gone. If you think you can actually get focus to lock on the head, like if it pops out into the direct sun or against sky for a couple seconds, or if it's at super close range, then certainly go for it.

You can often get a good shot when focusing on the nape.

Problem with that is the bird's body is often low contrast compared to the background foliage against the sky, so autofocus often fails to lock on the body alone, resulting in lots of frustrating hunting activity. Branches and foliage have the sharp edges and high contrasts that cameras like to lock onto.

bkrownd · Dec 2, 2007

a.dancy said:
Determining which part of the branch to focus on can be very difficult.

Can it? Usually where the feet are is the obvious place.

Sout Fork · Dec 2, 2007

bkrownd said and I paraphrase:

"The autofocus control on cameras isn't designed with photos of dark
camoflaged little birds in the bowels of bushes and trees in mind, so
you have to compromise with the camera. There's usually less than 2
seconds to get a photo before a bird moves, ...

...often your focus will just zoom in/out to surrounding foliage, bokeh or
la-la land. Once it goes hunting you have to fight it back to the right
range and your bird is gone...

...the bird's body is often low contrast compared to the background foliage
against the sky, so autofocus often fails to lock on the body alone,
resulting in lots of frustrating hunting activity. Branches and foliage
have the sharp edges and high contrasts that cameras like to lock onto."

Considering all of the above why bother with AF at all?

It seems clear to me that no AF system has the intelligence to deal with
the complex 3 dimensional environment found when photographing fast
moving passerines in the brush.

Would it be such a burden to simply use manual focus?
I assume we are talking about DSLR not PS cameras.

SF

All of the following taken at manual focus - how well would AF deal with
these situations?

gordon g · Dec 2, 2007

I use manual focus some of the time, but generally only where there is a lot of dense cover as in your second shot. In the other three, I would expect my dslr on centre point AF to cope without a problem (using focus lock and recomposing, ie holding the shutter button half-down to keep focus whilst recomposing. This doesnt work in AI servo mode)

a.dancy · Dec 2, 2007

Sout Fork

It is a little difficult to make a judgement with your images. I cannot access exif data and I do not know how far the birds were from the camera lens. However (not meaning to offend) in my opinion the 3rd image you have presented (bird looking up) is not sharp, I am sorry to say: you have focused in front of the bird or at best focused on the nearest part of the bird. The head is most certainly out of focus. My guess however is that my camera and lens would have got the shot(s) using auto-focus at a reasonably close range.

YellowBudgie asked the question why cameras get good focus when focusing on the bird's eye. The question does not confine to birds in a deep woodland setting. Of course the question makes some assumptions too. I have indicated why I focus on the eye as a rule. Sometimes it can be achieved , sometimes not...we just have to use what ever method suits us at our disposal. When hand holding a camera at a bird a long way off then in all probability you will not be able to hold the lens steady for the bird's head let alone the eye. If you are able to get a focus on the bird then take the shot, you will probably have sufficient depth of field to get a sharp image. If you are going to get very close to the bird for a frame filler...go for the eye. If you are using a very long lens wide open ...go for the eye. You can determine very quickly if your camera will focus. If it is too slow or hunts too much then go manual. Modern camera and lenses can still perform very well in very poor light. If you want to use manual focus ...fine...sometimes I do ...but often I do not need to. It helps if your camera lens has a focus limiter.

bkrownd · Dec 3, 2007

Sout Fork said:
Would it be such a burden to simply use manual focus?
I assume we are talking about DSLR not PS cameras.

Speaking for myself, I can't really tell when the focus is 'on' through a DSLR's optical viewfinder without a LOT of light, and the autofocus is much faster than I could ever be. Maybe it's easier with a $6000 lens, but not with my $1300 lens. However, I do wish I could flip the focus control between manual and auto faster, to get the lens back from hunting.

Sout Fork · Dec 3, 2007

a.dancy said:
"you have focused in front of the bird or at best focused on the nearest
part of the bird. The head is most certainly out of focus."

Yes. As a matter of fact, as I often do, I focused on the primary
coverts and let the head take care of it's self. It was a judgement call
not a fault - the second picture was taken the same way. A little
softness in the head was expected. You may not approve of it but there
you are.

Often the most interesting part of a birds plumage is on the flanks not
the head so I don't hesitate to ignore the head when focusing depending
on the bird. For the record the pic was taken at about 70 feet with a
tripod mounted 620mm fl scope (18x), 1/30 sec, ISO 800, very low light.

I don't do either PS digiscoping nor DSLR+conventional telephoto shots.
I do have a 500mm prime lens but find it just does not have the reach I
need for my interests - passerines in their natural habitat. I use long
lenses from 500mm out to 1000mm always on a tripod and often under very
low light and, of course, always having to deal with a paper thin DOF.

SF

Seeing as you are into head shots try this one:
1000mm scope barlowed (about 60x), ISO 400, about 100 feet, 1/250 sec,
almost full frame. Focus on breast. I'm at my limits as to quality and
reach with this setup.

YellowBudgie · Dec 3, 2007

Hi All,

Hearing everyones techniques and experience is a big help just starting out with DSLR bird photography.

It's also nice when people don't agree it doesn't turn into a flame war like on the netnews groups. I was browsing one the other day and it made me appreciate how nice it is here on BF.

Thanks,

Dana

Focusing on the eye (1 Viewer)

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