John, I may have burned more than 50 slide rolls with my FA 28-80/4, most of them spot-metered and notes taken accordingly. Never found any badly exposed for unknown reasons (that is other than my bad judgement according to my notes). It's aperture is certainly built within 0.5 stops tolerance.
Most likely your lens developed a fault on the aperture coupling lever. I'm quite sure the other sample will deliver correctly exposed slides (if you have the possibility to test it). Servus, Alin John wrote: jv> A week ago, I shot a few slide-films (Fuji 200) with my old SF1n and a jv> few different lenses. I used to make many slides in the past, but jv> changed to printfilm some years ago. jv> All slides made last week look fine, perfectly exposed - except those jv> made with the Pentax SMC 4/28-70 which all look overexposed at least one jv> stop. jv> I've checked the 28-70, but it looks perfect: aperture goes smoothly, jv> automatic stop-down mechanisms works fine. jv> I've compared the 28-70 with another similar model, both "made in jv> Japan"-versions, and upon visual inspection only one seems to have, at jv> identical focal length and aparture settings, a somewhat larger diameter jv> in the selected aperture than the other. To my view, not enough to make jv> for the one stop overexposure. jv> But again, both lenses seem to work perfectly. jv> Is this just a matter of tolerances, and have tolerances in modern jv> zoom-lenses become that large that they are just too big for slide film jv> ? Does anybody have similar experiences with the 4/28-70 ? - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org .
