On Mon, Sep 24, 2012 at 2:37 PM, P. J. Alling <webstertwenty...@gmail.com> wrote: > On 9/24/2012 1:54 PM, Darren Addy wrote: >> >> On Mon, Sep 24, 2012 at 12:10 PM, P. J. Alling >> <webstertwenty...@gmail.com> wrote: >>> >>> Naa, that's nothing, KEH also has the /truely/ legendary A* 135mm f1.8 in >>> stock at this very moment. Look fast it won't last. >>> >>> Almost $2K in bargain condition! >>> >>> >>> http://www.keh.com/camera/Pentax-Manual-Focus-Fixed-Focal-Length-Lenses/1/sku-PK06009016184N?r=FE >> >> Related: Sure makes you wonder what this "new" 135mm f1.8 is/was (and >> if it is for the digital age why it is still called an A* rather than >> a DA*) >> >> http://photorumors.com/2010/11/09/some-pentax-rumors-new-pentax-a-135mm-f1-8-lens-and-more/ >> > Not new old, and most digital ready lenses aren't any different from their > old non digital counterparts, except maybe for more effective non reflective > coatings on the rear element.
Pentax literature points out how the final element of DA glass is configured to direct the photons at right angles to the sensor to compensate for the fact that the sensor is most sensitive to perpendicular light. Film did not have this issue, hence FA glass (and before) doesn't do this so the image will be fuzzier, especially off center. My understanding is that all DA glass has been created with this astigmatism compensation specifically with sensors in mind. -- -bmw -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
