candc said:You might want to give the new 16-35 f/4 a try. I am not sure its suited for underwater photography, I think that's an an application like astrophotography where a faster lens is desireable but for general landscape shooting it's great. it doesn't go as wide as some would like but it goes to 35 and that is a plus for me. It's sharp at f/4 and doesn't need to be stopped down unless you want more dof.
+1. This!
Canon's offerings in the ultrawide zoom department for full frames were so measly that I was forced to forgo the zoom and ended up with the 24mm TS-E II L. Even 24mm is not that wide, so I would be forced to do 12 shots using the shift and rotate mechanisms. The cool thing about, though, was that the process would yield roughly the same view as a 17mm lens, while producing an image that's about 49 megapixels from my 5D2.
Now, they release the f4 16-35, and it's truly jaw dropping quality. Finally, a zoom with a decent range and world class optical characteristics. And for a very fair price too. And if you don't need f2.8, which most of us don't, then this is the perfect lens. If you do need it, sadly the f2.8 version of this lens is not in the same league optically. But it will get you 2.8.
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