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Difficulties with focus when taking birds in flight. (1 Viewer)

Roy C said:
Am I right in thinking that if you use all the focus points in AI servo mode the intial lock must always be on the centre point and then if the subject moves away from the centre, focus tracking can be picked up by another AF point.
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I don't think that - in reality - this matters too much: when I'm trying to get focus on a BIF, I'm not consciously thinking about the centre AF point (there's never enough time to be that precise!) but it seems to work out, more often than not.

And - given that I'd completely forgotten about this piece of advice - it might explain why sometimes things don't work for me quite as planned...
 
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Photovisions said:
The 1 series camera's do have a nice facility to help here (and why I bought mine). There is an option to turn focus search off. So what you do is roughly focus where the bird is (I tend to do this manually) and with inner 9 focus points on, track the bird and let the Al servo do the rest. The camera does not make large changes in focus to background or foreground objects. Of course I still need to lock with the center point initially.
Adrian
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Interesting as this facility is also on the 40D although I have not used it, must give it a go.
 
Yep, I've got mine to "off" all the time (from when I was trying to get the 40D to play nice with a TC) - it stops the lens from wasting its time and yours in a never-ending hunt for something to lock onto.
 
A good heap of advice indeed here, well done guys.
Yet, I still have to find a better (= faster, more accurate) way to focus than the centre point .. I do tend to use manual focus first if needed, then let AIServo do the rest: it seems to me this the best way to exploit my old 20D performance.
One more word: terns are not the best subject to practice on ;) .. in these days I'm struggling to get a fairly decent shot (which means filling all my flash cards)
Cheers,
Max
 
I've just been reading this thread and thought I'd pose this question:-
It occured to me (after trying and failing to capture Marsh Harriers in flight at Titchwell recently) that whilst I do use the centre point only on my 20D, if I were to use all 9 points, would the autofocus fail to recognise the background because it is so very blurred due to the camera being panned at the time and with a bit of luck one of the 9 points would be over the bird at the moment of shutter release? I should add that I too use AI Servo with the shutter button half depressed during panning to alert autofocus and IS. Any thoughts anyone?

Regards

Adrian
 
Hi Adrian
Yes, it should mostly ignore the background and all focus points should be used for shooting into the sky. Although please note I said mostly :)
Adrian
 
Boy George said:
if I were to use all 9 points, would the autofocus fail to recognise the background because it is so very blurred due to the camera being panned at the time and with a bit of luck one of the 9 points would be over the bird at the moment of shutter release?
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I'm certainly seeing that with my 40D, Adrian - tonight (yes, I said that yesterday too! ;)) I'll post some "all AF points, blurred busy background, bird in focus" shots from Tuesday just gone to illustrate this, and maybe provoke some further discussion...
 
FWIW I've just uploaded an album of BIF shots taken with my 40D at Colchester zoo recently. Every shot here was taken using all focus points and I have included resized full frame images and 100% crops. They're not that great, because the birds were pretty lively and tracking them was a real problem. Many shots are way off centre and in most shots the background is actually pretty busy. Even when focus is off, it is only because the AF has failed to keep up, or because my tracking was simply too poor. I do not see signs anywhere that the AF got confused and switched to the background.

Here's the album, displayed as a slideshow. There are 40 images and 40 crops, representing the results from 2 X 20 minute flying demonstrations....

http://picasaweb.google.co.uk/EezyT...hoto?authkey=tQzX3FlZxJA#s5198069123532806018

In many respects I wish I'd zoomed in closer but some of the shots were with my 70-200 and I was already at full stretch with that and struggling to keep the birds in the frame at all, much less centred. The problem with the zoo display is that the birds get such short runs it is hard to get a bead on them and then keep up.
 
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A lot of my BIF shots are not the great but I do manage to nail the occasional one. I must say that I cannot remember a single shot were the AF has locked onto the background.
 
A few BIFs - 40D/100-400mm and all AF points

I don't consider any of these to be particularly special (they are for the most part, test shots - coincidentally I was mucking about with all 9 AF points on Tuesday and was deliberately pushing my luck with iffy backgrounds) and I don't pretend that every single shot I took was this sharp and in focus, but then I'm by no means a BIF shooter.

Nevertheless, these were all (to the best of my recollection) taken using all 9 AF points: they're pretty sharp and in focus, and they'll do for me.

The fulmar and jackdaw are here simply to show that the 40D and 100-400mm can manage fast-flying birds too..!

;)

The one other thing these shots have in common is that they're all pretty big in the frame: I've got plenty of small-in-the-frame shots too, but in truth they don't look very good because they're small.
 

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Here is a couple that I took this morning. This guy was coming towards me at a fair rate of knots but the 40D and 400mm f5.6 kept pace very well.
 

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I have a related question which will show my ignorance. Since AI Servo is for moving subjects and One Shot AF for still subjects why not use AI Focus which according to the 30D manual automatically switches between modes. It seemsAI Focus would be useful if you are attempting to photograph a perched bird which suddenly takes flight.

Craig Thayer
 
Craig Thayer said:
I have a related question which will show my ignorance. Since AI Servo is for moving subjects and One Shot AF for still subjects why not use AI Focus which according to the 30D manual automatically switches between modes. It seemsAI Focus would be useful if you are attempting to photograph a perched bird which suddenly takes flight.

Craig Thayer
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I use AI servo just about all the time, even for perched birds. Must say I have not used AI Focus very much but the times that I have I was not impressed.
 
IMHO the best thing you can do with AIFocus is never use it. I found it was a useless compromise which never reacted quickly enough to what I was trying to do.
 
Keith Reeder said:
I don't consider any of these to be particularly special (they are for the most part, test shots - coincidentally I was mucking about with all 9 AF points on Tuesday and was deliberately pushing my luck with iffy backgrounds) and I don't pretend that every single shot I took was this sharp and in focus, but then I'm by no means a BIF shooter.

Nevertheless, these were all (to the best of my recollection) taken using all 9 AF points: they're pretty sharp and in focus, and they'll do for me.

The fulmar and jackdaw are here simply to show that the 40D and 100-400mm can manage fast-flying birds too..!



;)

The one other thing these shots have in common is that they're all pretty big in the frame: I've got plenty of small-in-the-frame shots too, but in truth they don't look very good because they're small.
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Pah!! eezy peezy stuff. Where are the Terns? B :);)B :)
(nice shots though)
 
A Theory.

Looking through my files I reckon that when the bird is closer to the camera than the background you've got a fair chance with ROF and centre point. When the birds closer to the background than the lens its centre point only and to be honest, as Keith said earlier you may as well go home and put the kettle on ;)
 
Hmmm, must admit that I always use manual focus - way more reliable than I've found any form of AF. But then I'm more of a macro person than birds, so go for the likes of dragonflies on the wing

Was quite pleased with this, being the first outing with the 100-400 @ Ynys Hir
 

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