Huh. Harder question than I thought. BTW, the lens in question is an bargain M 200 f4 that I got (well, in two days) for $70 from KEH. I'll post some results.
On Mon, Sep 13, 2010 at 4:51 PM, P N Stenquist <pnstenqu...@comcast.net> wrote: > > On Sep 13, 2010, at 3:02 PM, John Francis wrote: > >> >> I believe the issues surfaced when using lenses with a large maximum >> aperture (such as a 50mm/f1.4). >> >> Although Pentax never explained exactly what was happening, the most >> plausible hypothesis I saw was that the exposure metering in the K10D >> (and, I would assume, in later cameras) had some sort of compensation >> curve for the metering system based on the maximum aperture of the lens >> (presumably because of known problems with light hitting sensors at an >> oblique angle). An 'M' lens does not communicate maximum aperture (or >> the aperture to be used) to the body, so the exposure correction would >> not be performed (or would be performed using one fixed value for all >> 'M' lenses at any aperture). >> >> I didn't pay too much attention to the issue, because I decided to go >> with 'A' or later lenses back in '95 when I got my PZ-1p, so I rarely >> put an 'M' lens on any of my later bodies. And, in any case, I don't >> assume the metering on any DSLR is going to give me as good control of >> the exposure as I can get by looking at the histogram. >> >> The "green button" metering technique should get you close; just be >> prepared to apply some exposure compensation if you want it spot-on. >> That was necessary (at least with the *ist-D and K10D) anyway; from >> what Paul Stenquist says the K-7 may do rather better in this regard. >> > > I've shot a bit with a K 85/1.8 on the K7, but haven't used it extensively > and don't recall how successful those attempts were. I'll have to give it a > try and see how it does wide open and at a small ap. > Paul > >> >> On Mon, Sep 13, 2010 at 08:35:49PM +0200, Jens wrote: >>> >>> I may be using my M lenses too little. But I have never noticed any >>> exposure problems - except for those caused by the well known "slow aperture >>> syndrom", occuring when lenses are left unused for too long - or stored with >>> open aperture blades (on a camera or otherwise). >>> >>> I use a Seikanon wide angle macro lens quite often - which works like an >>> M lens. It's an absolutely brilliant lens - which I believe is made by a >>> company related to the later so well known Seiko brand. No exposure >>> problems, that I know of. Razor sharp. >>> >>> Regards >>> Jens >>> -- >>> Treat others as you would like to be treated yourself. >>> >>> On Sep 13, 2010 19:02 "Steven Desjardins" <drd1...@gmail.com> wrote: >>>> >>>> I've never really used an M lens on a Pentax digital, but I'm thinking >>>> about buying one. I know the green button trick, but how well does it >>>> actually work? Metering OK and all that? >>>> >>>> -- >>>> Steve Desjardins >>>> >>>> -- >>>> 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. >>> >>> -- >>> 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. >> >> -- >> 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. > > > -- > 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. > -- Steve Desjardins -- 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.
