I have been leaning towards the 17-55 but have been reading (on Canonâ€™s site) of dust problems where dust is working its way inside the lengths. I have a 7D and I like to take advantage of shooting in light rain and somewhat dusty conditions so the non-sealed 17-55 is a concern for me.
The 16-35 seems like an excellent lens and I am willing to fork out the big bucks if I find this to be the best option. Iâ€™m not buying lens today for a someday upgrade to FF but I am hoping to add (not upgrade) a 5D3 in a year or two. If I go with the 16-35 Iâ€™ll probably add a 50 f/1.4 hopefully the Mk II will be available and have a ring USM.
Any advice or comments on which lens based on my needs and any experience with dust in the 17-55 would be appreciated.
You can ignore the forum-verse complaints about dust for three reasons. First, while there are a few (vocal) reporters of problems, most won't speak up when everything's fine. Second, most reports indicate the problems are with older lenses. Third and most important, dust inside a lens is actually quite common (with any lens), and it has no effect whatsoever on the resulting images.
OTOH, water is a different story. If you actually plan to use the lens in the rain with your 7D, get the 16-35L II. Do budget a little extra for a quality UV/clear filter - that's required to complete the sealing on the 16-35 II. I'd recommend a B+W MRC or Nano coat (and the 82mm versions aren't cheap).