I personally love the 200mm f2.8, which I always shoot wide opne. With the help of a microfocuser, I can get sharp, pinpoint stars edge to edge. I am currently using the lens coupled to the Atik 314. Although this is not the ideal combination in temrs of image scale, I can still achieve nice round stars and the FOV is decent. When m tired of using ccd's, I'll throw the lens on the DSLR for some really wide views, and the reults are superb. For under $1,000 USD, this lens is the best option for fast, wide field imaging on a budget, although the geoptik adapter will add to the cost. Here's my setup. I guide with a 400mm f/5 orion shortube. It is overkill really, but by inmaging at half of the guide FL, i can get up to 20- 30 min subs no problem.