I've been lurking this site for the past several days trying to garner as much info as possible.
I'm looking to get a telephoto zoom lens for my new XTi for animals, whether it be at the zoo, at a public lake (ducks/geese), or in the field.
I was looking at the 70-300 f/4.0-5.6 IS USM. The fact that it has both the IS and USM makes it a very interesting lens. But the 5.6 at 300mm has me slightly worried. I'm sure this should to fine in daylight, but should I be a bit more concerned and look into a telephoto zoom with an f4 or better throughout the entire focal length?
I was looking at the 70-200 L series, but both the 2.8 and 4.0 with IS and USM are a bit outside my budgetary range. I could get a 70-200 f4L with USM for the same price as the 70-300 f/4.0-5.6 IS USM, but I'd be losing out on the IS.
Anyway, unless I spend the $1k+, I'm going to either get the 70-300 f/4.0-5.6 IS USM and sacrifice the f-stops or get the 70-200 f/4L USM and sacrifice IS.
Any opinions either way?


