On 9/03/06 3:49 PM, "Godfrey DiGiorgi", <[EMAIL PROTECTED]> wrote:
> From another conversation, I believe the reformulation of the D-FA > 50mm Macro from the FA 50mm Macro was due to back-reflection issues > with the digital bodies. I've seen work with both lenses and they > both look very good (with a digital body) so I suspect this only > happened in particular circumstances but Pentax felt it was > unacceptable. My understanding from Pentax source is that the FA version macros were too costly to manufacture and distribute and every single copy they sold, they lost money. So, they changed the barrel designs (Interpretation: plasticize) and re-offered them as DFA. In retrospect, this coincide with their decision to collaborate with Tokina (not OEM) to reduce the mfg cost. Optical formula is exactly the same as the one for the FA versions. However, because of the D designation, they certainly added some coating such as the coating on both sides of some element (s), particularly the rearmost glass. Other than that, they should be the same as the FA versions. Cheers, Ken -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net
