by Ian Gains » Wed Jan 09, 2013 10:36 pm
Hi Derek,
I bought a 7D 6 months ago & got the 17-40mm L and 70-300mm L, & I've been happy with both. I've been in the photographic game for 25+ years so I researched the available Canon lenses well - IMHO don't bother with any other manufacturer's lenses as they aren't as good. I suggest that you read some reviews on line of the lenses that interest you & you will find that Beau's recommendation for the 70-200mm L IS II is fantastic, but it is a $2000 lens. For what I do, the 70-300mm is more compact, good optically, & translates to a 112-480mm lens on the 7D. Don't worry about the technical jargon in the reviews, just get a feel for how good a lens is & will it do the job you want it to. Do you need IS ? I decided I did for the telephoto zoom lens, but that I could live without it for the 'static park at airshows' lens, hence the 17-40mm which doesn't have IS. You pay more for larger maximum apertures too ie. an f/2.8 lens compared to a f/4 lens, but the f/2.8 is heavier, takes larger more expensive filters & can weigh twice as much, plus it will be double the price. When you can increase the effective film speed so easily with DSLR's, & I lug my gear overseas, I was happy to get a lighter, cheaper lens that is still good optically (it's better on a 7D than 5D as the 7D uses the 'sweet spot' of the optical field.
Ask some questions when you have read some reviews. The 24-105mm L IS seems like good value for money, but it's performance is comprised at 24mm, both on a full frame sensor body AND to a lesser degree on the smaller sensor series, including the 7D. If you can live with this, it seems pretty good throughout the other focal lengths. Google lens reviews - Photozone is pretty good, & there are several others that should be easily found.