I need a wider angle lens for my 18mp crop body, and am thinking about either one of the ef-s zooms or a fixed prime. Actually, I like primes since I bought a 100mm macro and *might* get a ff body sooner or later.
Since I want to buy a ultra wide, too, there actually is no need for 15/17mm, and neither for 70mm because my 70-300L starts to cover that. And the difference between 35-70 is bridgeable if I move towards the object or crop the hopefully sharp pictures of the 35L.
* Does anyone use the 35L on a crop body and can share some real world experiences (sharpness, af speed, dust/sand resistance due to missing weather sealing)? Do you think it's overkill to use this prime on a crop body, because it uses only part of its potential?
* There is talk of a replacement for this lens - I guess it would be clever to wait for it and then get a used copy of the older one? Or do you think because the 35L-II will be double the current price, the 35L-I won't go down?
I picked up a 35mm f/2 for crop but later upgraded it to the 35mm f/1.4. I liked the 35mm f/2 on crop but based on your previous comments, I don't think you'd like it (it's like the 50mm f/1.4 but cheaper)
I haven't tested the dust/sand resistance
AF is reasonably fast and very smooth (no lurching or hunting). Slight delay if you go from MFD to infinity, for normal shooting it feels fast. Compared to the other lenses I own (Sigma 85mm, 35mm f/2, 50mm f/1.4, 135mm f/2), only the 135mm f/2 has AF performance in the same ballpark. It has plenty of "sharpness". It is quite sharp, see photozone reviews for some objective tests (even the cheaper 35mm f/2 is pretty sharp on APS-C)
Whether or not it's an overkill -- well, what are the other options ? You have the Sigma 30mm (very soft in the corners), the Canon 35mm f/2 (sharp, but cheaper build, pentagon bokeh, ancient noisy AF) The 28mm f/1.8 is very soft at wider apertures. You could look at Zeiss's offerings (I know their reputation but haven't used them), but that will put you in a similar price ballpark and you lose AF. So I don't think it's an overkill -- if you don't want to live with the flaws of the budget lenses, you're looking at $1000 or more.