On Tue, Apr 04, 2006 at 09:48:58PM -0700, Shel Belinkoff wrote: > Assuming the same optical formula, is the only difference between the F and > FA lenses the power zoom feature, or are there more differences? Any that > really matter wrt use on the D cameras?
Not all FA lenses are zoom lenses, but they still get the FA name. I think that the FA lenses were the first ones to include MTF data in the ROM chip. That's only important if you use that feature by selecting the appropriate program line. It's also possible that there is some other lens-to-body communication (focus distance?) that is used in multi-segment metering and/or flash compensation; Pentax have remained silent on the detailed differences.
