Seeking ways of tracking birds in flight with 500mm lens

Started May 23, 2013 | Discussions thread
brandrx Forum Pro • Posts: 28,337

Greyser wrote:

brandrx wrote:

Hi Barry,

I just received a Pentax K-5 II yesterday and it sure looks like the Expanded Area Auto Focus is the way to go when tracking birds in flight. I havn't actually tried it against birds yet but a couple of tests I made indicate to me that it should work like a charm. I think it tells about it on page 115 of the K-5 II manual. I don't know if the page number would be the same for the K-5 IIs though.

I am looking forward to giving mine a go against some BIFs soon.

Please keep us posted! I decided do not go with II or IIs after Mike posted nasty respond about Sigma 500/4.5 hunting.

Hi Greyser,

I suppose you are talking about this post made by MightyMike, huh?

FWIW: Yesterday I focused into some branches at a House Finch. I was not using the Sigma 500/4.5 but rather the Sigma 400mm f5.6 + 1.4X TC and I was using Expanded Area Auto Focus. My K-5 II had no problem locking on the the head of the House Finch. The other thing I noticed about Expanded Area Auto Focus is that once it locks on and you then completely loose the subject out of the focusing area the lens does not hunt. It seems to stay at the same approximate focusing distance until you put the subject back into the focusing area. I tested this against a subject that was completely isolated from anything around it. It was about 200 feet from me. Behind it was a mountain at about 2 miles. I locked on to the subject and then moved the camera in such a way that the subject no longer covered any of the Expanded Area Focus Points. The OOF mountain that was 2 miles in the background covered the focusing area. The lens did not hunt but remained at the approximate focus distance of my original subject. I then placed the subject back into the focus area of the Expanded Focus points and it again was locked onto my original subject. This was just a simple test and of course it will require more testing before I can be sure. I will try to keep you informed.

All that I have written above is dependant on keeping the shutter button half-pressed. Also, when you first begin your focusing it will only use the focus point you choose to aquire and lock focus. Once it does that then the Expanded Area Focus points can then come into play.

As I wrote above, I need to test this more thouroughly before I can say absolutely for sure that it works as I have written.



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Ron - 'We don't have time to go take pics this afternoon Carl.'
Carl - 'What do you mean? It will only take 1/1000s.'
'Keep your eyes looking forward. However, glance back now and then to see where you've come from. It will put a smile on your face.' ~ brandrx

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