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/