Yes, 25-50 is a completely different story. While at 4.0 it is a bit soft, already at 5.6 it's getting very sharp, with extremely deep DOF. Doesn't need 8.0, there will be no more sharpness. I had some difficulties to focus it, so, I used a distance scale, simply like this. Very contrast lens, with good color rendition. Some geometrical distortions are present, so one has to watch it, or improve later. Vignettes a little bit, but not as crazy as 28-50. I may recommend it with open heart, even today. Especially AIS version, with colored diaphragm scale. It has slightly improved MC, the rest is the same. LZ PS. It has one small screw on the front ring. Do not let it gets loose. Otherwise, you may get two halves in the middle of the shooting! Time-to-time, make it tight! Beautiful lens it is! LZ