TG> 15-30, there is no chance of using any filter on the front lens cover ring. TG> it vignettes noticeably until zoomed to at least the 20mm mark with just the TG> ring attached. not being able to use a filter is limiting, but not as TG> limiting as it could be.
With the 15-30, I found the ring vignetted most of the time. Same with 14 sigma. I think it was made for a DSLR with bigger crop (like the early sport Kodaks or Sigma's SD9). Filing away corners to make it sort-of tulip shaped helps. TG> tell myself never again. however, it's the only program that knows how to TG> read the lens information from the EXIF. I think there are others like Exifer and similar, who can decode (some) of the manufacturer's hidden EXIF data. They are continually updated so they could know the IstD's already. Best regards, Frantisek Vlcek
