2010/2/25 Miserere <[email protected]>: > C'mon Jostein, you know what I'm talking about :-) On lenses > intended for digital sensors the rear element (at least) is coated to > minimise reflections coming off the sensor that could bounce back from > the rear element to the sensor, causing a ghost image. This coating > should be the easiest to observe tell-tale sign of a made-for-digital > lens.
Observed how, exactly, eh? You can't trust the colour of the coating, and the only equipment I have for assessing the light transmission is my digital camera. Which, as I told you, give very decent results. IIRC, the 645 FA 35mm was released just a few months ahead of the *istD. I believe the digital coating was already developed then, so it's at least theoretically possible that it has somesuch. Oh, and btw, I think there's nothing in the K-mount that beats 645 optics in lens stacking or bellows for extreme macro. Such arrangements bring out the worst in any lens combinations with regards to chromatic errors, but the 645 lenses continue to surprise me in this regard. Until this year I had used the A*300/4 and FA 75/2.8 stacked (4X magnification), the A 120/4 macro on bellows or the 75/2.8 reversed on bellows for up to 2.5X. All with good results. This winter I have borrowed a FA 150/2.8 and stacked it with the 75mm, and that's even better in the 2X area. Jostein -- http://www.alunfoto.no/galleri/ http://alunfoto.blogspot.com -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
