David Kernaghan , Feb 01, 2006; 10:31 a.m.
Alfie, the 24mm focal length is one I personally like (the perfect complement to a 35mm), and currently have the 24 ASPH M. I previously owned the 24R, and finished up trading it for a current 28R, a focal length I don't particually like.
The performance of the 24R is not up to the standard of the current 28R, and nowhere near the 24M. The 24M is in a class all by itself.
The 24R is as good as the 24 2.8 Nikkor, that most people think highly of. The differences in my experience, the 24R has better imaging in the center of the frame, with the Nikkor being better in the outer areas of the frame.
My sense is that the floating element design causes compromises that are more noticable in the 24R than the Nikkor, the Nikkor being more even edge to edge.