I'm intrigued that people seem to like the FA 300/4.5 clutch mechanism and focus feel better, since the F 300/4.5 seems pretty nice to me in those respects.
My girlfriend and I went down to the local pond to photograph the baby ducks tonight. She had her *istD and the F* 300/4.5 that I acquired recently for her, and I had my D100 and 300/4.5 EDIF Nikkor. It's hard to compare sharpness between setups since although the two cameras have identical sensors, they clearly produce different results from them. Also I was manual focusing, which on the D100 is unpleasant in funny light with a slowish lens, whereas she was AFing most of the time. Some things were obvious, though. 1) Both lenses show color fringing, which is to be expected with an IF design as I understand it 2) The bokeh of the two lenses appears to be different in character. I'm not a bokeh afficianado, but I can see a difference even if I can't describe it. 3) The F* lens handled backlight MUCH better than the Nikkor. It didn't have a filter on it (haven't gotten around to buying one) whereas the Nikkor had a fairly clean Hoya UV on the front, but I suspect that the difference is primarily in the coatings and perhaps the optics themselves. The Pentax built-in hood also appears to be a little longer, which would have helped combat the low-sun backlight. 4) 300mm is too short for ducks, even on an APS-size-sensor DSLR. Overall, I'm impressed with the F* 300/4.5. I'm still hoping to set up the studio lights and take some portraits with the various 300s now that my more scientific test target is no more. DJE
