This lens opens up a lot of possibilities for me. Not to repeat the many positives that others have commented (great low light, sharp wide aperture, good background separation, etc.), this lens requires something from me. Focus is rated more for accuracy than speed and seems fast enough in actual use. I've learned to focus calmly before I press the shutter button. Focusing on the F100 has worked flawlessly so far. On some shots where the subject was running towards me (didn't have time to check focus), I was surprised to find that focus was fairly quick and clear. Getting a good off-white blur portrait requires the camera/lens to be fairly close to the subject, which can be an issue for some. Either way, this is a great prime lens and has become another popular lens alongside the 105 DC.