jmb schrieb: > > John Francis wrote: "the 1.7AF adapter with the A* 300 (and also the 200)" > > John, > > I just learned about the existence of the Pentax 1.7af adapter last > night. I also > am interested to see how it performs with the M lenses and the *istD. I > gather > from the name that it also functions as a 1.7 teleconverter. How much of a > light loss is there?
Simple math, take the 1,7x as the overall multiplicator: 50mm f/1.4 becomes 85mm f/2.38 - so it's about one and a half step :-) 135mm f/2.8 becomes 230mm f/4.8 and so on... Thomas
