I am planning to buy a second hand Nikon 20mm and after reading several reviews and rankings it seems to me that the best choices are: a. 20mm 2.8 AF or MF, price: +/- $300-350, ranking: 4/5 (general) b. 20mm 3.5 MF, price: +/- $170-220, ranking: 3/5 (at infinity), 5/5 (close up) c. 20mm 4.0 MF, price: +/- $150-200, ranking: same as b. As I am interested in both landscape & close distance photography (for dramatic effects) options b & c may not be as good as option a; however, the performance at close distance may be superior (and the price is tempting). I will appreciate if you could share your experiences with any of these lenses. Thanks!