without a FF camera, there is no fair way to test these lenses. You need to compare various lenses at same angle of view, not same focal length to get fair comparisons. Wide angles designed for FF are not going to be as good at same focal lenght as lenses not having to cover ff.
JC O'Connell [email protected] -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Bill Lawlor Sent: Wednesday, April 01, 2009 8:24 PM To: [email protected] Subject: Re: Found Converter K and screwing again (warning, lens tests!) Thanks to those who offered suggestions. I found my screwmount to K converter in a box of Canon FD lenses. (What was I thinking.....?) I wanted to try a favorite Spotmatic lens on my K10D. It's a Carl Zeiss Jena 25mm 1:4 Flektogon. A mighty glass using 77mm filter. I got it at a flea market in Rome in 1991. It was almost welded to my Spotmatic for years. The Pentax SM converter installs and uninstalls(a concern with these things) without problem on the K10D but the Flektogon has play when mounted. About a quarter inch of rotation loose. I had problems holding everything together during exposures and images were unsharp. I found a way to eliminate the play but images were still unsharp. Eventually, I discovered the focus was off a bit when using the scale to focus.(TTL focus is quite difficult with the K10D screen and the F4 ap on such a wide angle) Focus confirmation to the rescue! I never neded it before. The Zeiss 25mm is at least as sharp all across the frame as my "best" SMC-M 28/3.5 wide angle. Just for fun I compared the 25mm and 28mm to the 18-55 kit lens. To my utter surprise the kit lens at 24 and 28 on the same test target (a shingled old building nest door) was almost as good as the prime lenses. All tested at f8, BTW and viewed at 1:1 in LR2. At moderate magnifications there is no practical difference. Well, it was fun, anyway..... Bill Lawlor -- 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. -- 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.
