listen, you posted this "theory", not me, you said all tests were done at the same light level. If the body is setting the SHOOTING aperture setting with the lens on "A", the metering sensitivity is not an issue no matter what fstop setting you use because the lens is wide open during metering when the lens is set to "A" regardless of what the user/body tells the lens what aperture to shoot the exposure at so how is metering sensitivity or metering range ever an issue in those circumstances unless ALL tests were done at too low a light level for even the wide open lens which of couse would make all the tests meaningless ? ? ? jco
-----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Godfrey DiGiorgi Sent: Wednesday, January 24, 2007 11:58 PM To: Pentax-Discuss Mail List Subject: Re: A test of meter/exposure calibration between *ist DS and K10D JCO Listen, you mindless nincompoop, the comment I made with regard to variation and body controlled aperture setting is expressed in exactly these words: > The remaining four rows show what the in-camera reflective meter > nets at the same aperture settings ... first two using the body > controlled aperture, the next two using the lens' aperture ring. > Note that there is more variation here between f/4 and f/16, even > with the body set aperture setting, because you're hitting the > bottom of the meter's sensitivity range. Then, in the next two > rows, you see that at f/16 the Manual-semi automatic stop down > setting really does bottom out and the f/16 exposure is well > underexposed. which says that the reason for some variation at this setting *EVEN* with the body controlls aperture setting is that you're hitting the bottom of the meter's range. Look at the exposures in the table, K10D column, sixth row: the camera set ISO 200 @ f/16 @ 8 seconds ... the K10D meter has a range of EV 0.0 - 21 EV (given ISO 100, 50 mm F1.4). With body-controlled aperture, lens on the "A" position, metering is wide-open at f/2, so the meter is being asked to perform at EV -1, one stop past its rated limits of accuracy. Some variability at the bottom limits of the metering range in any metering system is quite normal, certainly past is, and the metering variation is about 0.3 EV. That's very acceptable performance in my book. G On Jan 24, 2007, at 7:56 PM, J. C. O'Connell wrote: > What is "allowed" by the mfgr. and what is acceptable to the > photographer is two different things of course. 1/3 stop may be > fine for > color neg film but it might not be for DSLR if you dont want to have > to tweek all your images to get them to match on density > when changing the fstop/shutter speed combination under > same lighting conditions. He specifically stated there was > visible ( not just measurable ) differences didnt he? > jco -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net
