On the topic of super wide angle lenses Alan Chan wrote:
Generally all super wide angle lenses have considerable fall-off of resolution and of contrast from image centre to border (and yes, Raimo, they do have light fall off, too). And of course some lenses are better than others.Could this be a problem with Pentax, instead of all SLR wide angles?
I remember a UK magazine did some test and they said while the Pentax 15/3.5 was the most flare resistance (along with T*), Zeiss & Nikkor 15mm had better sharpest from centre to corners."Sharpness from centre to corner" is subjective. I have seen other test (Foto Magazin) telling that the Pentax 15/3.5 was as good or better than the Zeiss, Leica and Nikon equivalents - which I tend to believe, as the designs of these lenses are very, very similar. Maybe the new Leica 15/f2.8 is better, though.
The Pentax 15mm, they said, was okay from f8 up, but still not particular good against Zeiss & Nikkor. Consider the Nikkor had flare problem, Zeiss was the clear winner of the test.My own experience with the Pentax 15/f3.5 is that wide open it is OK in the centre and not so sharp at the border. At f8 it is very sharp in the centre and sharp enough at the border but still a long way from a normal lens or from a lens like the K28/f3.5.
Arnold
