[LRFlex] Re: eagles

Thanks Doug.

Case closed!

Elliot

----- Original Message ----- From: "Doug Herr" <telyt@xxxxxxxxxxxxx>
To: <leicareflex@xxxxxxxxxxxxx>
Sent: Monday, February 21, 2005 4:38 PM
Subject: [LRFlex] Re: eagles


on 2/21/05 11:55 AM, Dr. Elliot Puritz at drpuritz@xxxxxxxxxxxxx wrote:


Hi Doug: Well, at the golf course today one of our members was using his
Canon EOS 1D ( I think ) with a Canon 500 mm lens and a 1.5 extender. The
Eagles have two Eaglets in their nest which sits high in a Pine Tree about
one quarter mile away. What was interesting was the auto focus feature that
enabled him to capture the flight of the Eagles. He told me that the lens
and camera have "predictive" auto focus so that the camera quickly "knows"
where the subject is going to, and focuses there. Rather amazing.

Elliot


Predicting the flight of eagles isn't that difficult:

http://www.wildlightphoto.com/birds/accipitridae/baea00.html
http://www.wildlightphoto.com/birds/accipitridae/goea01.html

other birds too:

http://www.wildlightphoto.com/birds/accipitridae/ssha00.html
http://www.wildlightphoto.com/birds/pelicanidae/awpe00.html
http://www.wildlightphoto.com/birds/laridae/hegu00.html
http://www.wildlightphoto.com/birds/rynchopidae/blsk00.html
http://www.wildlightphoto.com/birds/recurvirostridae/amav00.html

Note that all these flight photos were made with f/6.8 Telyts. IMHO a good
viewfinder and a responsive lens are best: SL, SL2, R8, R9 and an f/6.8
Telyt.

What a predictive AF system does is observe the dx/dt of the bird, use the
known dt of the shutter lag, and assuming a straight-line flight, calculate
a new dx from the time the shutter relase was pressed. It can't predict
zigs or zags.

Doug Herr
Birdman of Sacramento
http://www.wildlightphoto.com


------
Unsubscribe or change to/from Digest Mode at:
www.horizon.bc.ca/~dnr/lrflex.htm
Archives are at:
www.freelists.org/archives/leicareflex/ 

------
Unsubscribe or change to/from Digest Mode at:
   www.horizon.bc.ca/~dnr/lrflex.htm
Archives are at:
   www.freelists.org/archives/leicareflex/

Other related posts: