Originally posted by eddie1960 there was 2 versions, the first was FF the second for the crop. the difference was in the hood i think, the DA the hood would Vignette on FF. I think they may have had some issues with FF performance so they limited it. 25 would be very wide on a full 645 frame (15mm on 35mm equivalent)
No, there are two versions, one is DA (just released this spring in the US) and one is D FA (released a year or two ago in the rest of the world/asia).
DA means that it is only usable on the cropped sensor (33x44mm) on the 645D. The D FA is also usable on the other 645 film cameras (full frame 6x4.5cm)
What I'm trying to determine, mostly out of curiousity at this point as I already own the D FA 25mm, is whether the optical formula was actually changed for the DA, or if they just put a different lens hood on it (this causes the full frame to vignette on the DA version of the lens) and labeled it DA.
The D FA has pretty significant CA's, which are not ideal, but can be mostly dealt with in post. I'm wondering if these were correcty to an extent on the DA (newer) version of the lens.