Sigma 15mm f/2.8 EX Diagonal Fisheye - 9.5
Is this lens worth the price? Yes
Would I buy this lens again? Yes
Pros: extremely wide angle (equal to about 16 or 17mm after 1.6x crop, even better on a Nikon 1.5x) for a low price, good build quality, quiet AF for a non-HSM motor, smooth focus ring, accurate AF, good lens cap design, low flare (very important for an ultra-wide). fisheye effect is easily corrected with free software with excellent results. very sharp at f2.8 - as sharp as my 50mm at 2.8.
Cons: does not sharpen up as much my other lenses when stopped down to f4, AF/MF switch is stiff (but that's just nit-picking - no point deduction)
Would I buy again? Yes. with affordable FF on the horizon the 10-20 and 10-22 lenses are not as appealing IMO. the 15mm would become even wider on FF, and the semi-fisheye effect is sometimes welcome or even undetectable (at least on 1.6x).
tamron 28-75 f2.8 XR Di - 8
note: this is a revised update to my previous review of this lens
is this lens worth the price? yes
would i buy this lens again? leaning towards no - see below
pros: extremely high sharpness and contrast for a zoom. Iím not kidding- it beats out my two L and even my ultra wide prime. second in sharpness and contrast under the 50mm f1.8 mk I out of the lenses i own. great price, good build quality, small and light - especially compared to the competition, decent macro performance for a lens of this type (though not at all comparable to real macro performance) AF noise level well controlled when the AF is not hunting. When it does hunt, the noise can be a little distracting, but is a lot quieter that some non HSM sigmas and non USM canons. An incredible value for itís price/optical performance.
cons: slowish focusing, not alway accurate at 75mm. EDIT: I originally bought this lens for indoor use of moving subject and wasnít totally satisfied with it for this purpose, but I bought a bounce flashed and didnít use it much for this purpose since. Recently I was in a situation once again with dim lighting and moving subjects, but couldnít use a flash. For this purpose this lens failed miserably. Instead I opted to use my 17-40L f4, figuring that shooting a f4 and getting darker pictures is much better than a lens that would not AF at all. the 17-40L f4 on the other hand was VERY quick to focus and with it I was able to capture some very nice images that I was very pleased with. For this reason I bumped my rating of this lens down from 9 to 8. This used to be my most used lens but the AF was always hesitant, and it seems that the 17-40 always ends up taking over itís purposes due to the Lís superior AF capabilities.
would i buy it again?: I donít know at this point. Maybe not. I think I might have to replace this lens with two fast focusing primes. Why? Because while the sharpness and contrast are incredible, but I keep missing shots with this lens. There really isnít any competition at this price though. The canon 24-70L f2.8 seems to deliver in the AF department but from the examples Iíve seen, isnít better than the tamron optically (except maybe bokeh) and costs about 3x more. Itís too bad - with good AF speed and accuracy this would be a killer lens, and on FF the focal length of this lens would definitely see a lot of use.