For an ultrawide zoom it is sharp (and better than you would expect even wide open), but the sharpness is nothing like that of a 50mm prime for example. It has a very warm colour rendition, especially of the greens. Focus speed is average and accurate on my example (not that focusing at 11mm is difficult as pretty much everything will be in focus anyway). Build quality is generally good, but the zoom and focus rings seem cheap in comparison and don't inspire confidence - my focus ring has some slack too. I wouldn't want to knock this one around or get it out in the rain etc. Does take filters, but you may need slim ones to avoid vignetting (my B&W standard pola vignettes) - I can hold Cokin/Lee grads etc manually flat against the lens ok.
Can be tricky to use, the perspective at 11mm is so wide that you need to be really close to something of interest. I find it works best really low to the ground for landscapes (prepare for crawling - I had an unpleasant encounter with an ants nest on my last outing with it lol). It can make good panoramas with interesting perspective. It does have funky barrel distortion (especially close up), but it is pretty easy to correct in PP. It tends to have green/magenta or blue/yellow CA at high contrast edges in the corners, mostly correctable via sliders but you may need to finish the job manually.
It is certainly fun, and perhaps the best performance/value ultrawide for a crop sensor. Also as it seems in permanant short supply you can buy it, try it and either keep it or get most of your money back if you sell it. I don't use it as much as I would like but I don't plan on parting with mine anytime soon.
Bottom line, certainly good enough for stock stopped down a little, if you have the more conventional focal lengths well covered then give it a shot (but if I had to choose between the 11-16mm and good 18-28mm coverage (with whatever lens) I would go for the 18-28mm first.
Thank you so much for your great post: it's really full of great information! Even better than a review!!! ;-)
Of course I don't expect perfect sharpness from a lens like that (I have the 50mm prime and it's simply amazing!); the important is that it allows shooting photos that are not too soft.
I read about barrel distortion and CA about this lens, but everybody seem to find it quite easy to correct in post production, so maybe that's not a so big issue. By the way, the new Lightroom 3 has a built-in automatic distortion and CA correction based on lens profiles that seem to be working pretty well...
My main goal for using this lens wouldn't probably be stock...I think I would use it mainly while hiking in the mountains (I live in the Alps, so chances of shooting in that kind of landscape are abundant for me :) ), even if I think a wide lens can be very good for many creative purposes...
I own a 18-200 lens, so for me the 18-28 range is covered (even if there are much better lenses for that...I know that...). Do you have any suggestions for a lens in that range?
Or, since you're a much more experienced photographer than me, do you have any other suggestion about "must-have" lenses?
The 18-200 is a very decent lens, and if it suits you and does not cause you any problems then there is no real reason to change it. If it is causing you rejections for focus (or you find it not fast enough) then perhaps consider something sharper. The 24-70 and 70-200 are sharper and faster but also much more expensive and far heavier which is probably a serious consideration for mountain trekking.
Must have lenses, hmmm, I guess that depends on what you shoot. Any of the pro range Nikkors will be good enough for stock. You already have the 50mm which is very light and sharp. If you really want to travel light you could also consider a wide prime and leave the zoom (but I recognize zooming with your feet on a mountain may not be practical!).
Ncn, you are right, it won't work on FX. But it is almost 1/3 the price of the 14-24 and it retains its value well so it is easy to sell on if you need to. So you could buy it for around £500 and sell it in 12 months for around £400 which is a lot cheaper than renting! You do take a risk in that if it gets a major update before you come to sell (or you damage it) that it's value will drop. The 14-24 is certainly better, but also much heavier and you can't easily use filters which may be important for mountain shots (ie an ND grad to balance the sky).