Herman Hiel , Sep 09, 2005; 07:06 a.m.
Beau, I do not have a 500f4.5. I do have the IS version and on a recent vacation I was in a car with a driver, wife and 6 year active kid. I shot on a beanbag (with all of the others not being as still as I would have wanted) with a 1.4 AND a 2x converter and my digitalpics come out fine. I do not know whether you need this multiplication (how big are the birds you want to shoot?) or whether a non IS could pull this of. This might help you choose. Have fun shooting.