Does anyone have a serious comment about this lens.
What about: Vignetting? Flare? Sharpness at f4 f5.6 and f8, Color?
I think of buying one, but it is a very old design. Surprisingly German magazine colorfoto tested it as a very good lens, better than its competitors from Nikon and Canon. But not as good as the 21/2.8 from Zeiss. The 18/4 is much cheaper and lighter dan the 2,8. I prefer the 2,8 if the performance is very good indeed.
>i already stated that you will have to stop down to 8 or 11 to get rid of light-fall-off. lens is sharp enough, colors are good but there are flares like in all super-wide-angle lenses if there is a light source in the image. i had tested a 15mm and i have seen unbelievable irregular curved vertical lines at left and right side of a horizontal image. buy a g1 or 2 with 21mm and you will get more performance.]
i will discuss the 15mm-matter with experts and check a second lens which is hopefully of better quality. some people say there are some 45mm-lenses which are inferior to others. maybe one has to compare different lens-type at the same time. my lenses seem to be of the same superbe quality. i do not like the bluish taste of canon fd-lenses. its only a problem if using certain slide-films.
I have the 18mm in the Rollei fitting and assured my Nikon using friends that it gives no pincushion or barrel distortion and had not noticed any vignetting because I had used it at f8 or lower - then I read a magazine test (slr magazine) and tried it at max aperture - yes it vignates badly but still, for buildings there are tripods !