I don't recall making that argument, because what I was complaining about is that stop down metering takes away from your metering sensitivity at the low light end, dramatically so at smaller apertures. That is just one of the reasons why open aperture metering became the defacto standard in the mid 1970's (there were other good reasons too).
That said, ASSUMING THERE IS ENOUGH LIGHT, stop down metering will always be more accurate than open aperture metering because there are two less variables to "go wrong" and introduce errors. One is the sensing of the apeture setting ring and the second is the actual aperture opening size compared to what the camera thinks it will be. Both of these are non factors with stop down metering so stop down metering will always be more accurate ASSUMING THERE IS ENOUGH LIGHT to do stop down metering. So, stop down metering has the one plus to it, but if the aperture sensing can be made accurate enough and the actual stop down apetures are accruate enough, the very small error that open aperture meter adds is totally outweighed by the pluses (faster operation, better low light sensitivity, brighter viewfinder) gained by going to open apeture metering. that's why it has been the standard for 30 years. JCO -----Original Message----- From: Gonz [mailto:[EMAIL PROTECTED] Sent: Thursday, November 04, 2004 4:22 PM To: [EMAIL PROTECTED] Subject: Re: Stop Down Metering on K, M, LX Shel Belinkoff wrote: > Hi Christian, > > A couple of reasons. First, a week or so back JCO made the assertion > that by metering thru a lens set at the taking aperture, measuring the > actual light transited rather than having the camera essentially > calculate the exposure, would result in a more accurate, or precise, > exposure. I'd like to see if there's any truth to that, and if > there's any practical difference. > My guess would be that the difference would be so tiny as to be insignificant. Esp with film since there is so much latitude. But if you are really interested in testing this, an interesting way to do this would be to use Mark's trick with the *istD, that is, mount the lens so that it is not fully locked, to a position such that the lever that keeps the aperture wide open is not engaged. I believe he said it was about 1/8 of a turn or so, but check with him. This is ok for tests like you want to do, but I would not recommend this for everyday shooting, as the lens is in somewhat of a precarious situation not fully locked in and could fall off. > Also, I want to compare two similar lenses, one being a Super Tak that > can only be used stopped down on K bodies and the other being a K > mount version of the lens. It would seem that if the metering styles > used were the same (assuming there IS any difference as suggested by > JCO), the comparison between the two lenses may be more accurate. > > However, I doubt that I'd want to shoot that way when making regular > photographs. > > Oh, there's a third reason: I've just a little too much time on my > hands right now <LOL> > > Shel > > > >>[Original Message] >>From: Christian <[EMAIL PROTECTED]> > > >> > Is there a way to use a K-mount lens on the K, M, or LX bodies with > > stop > >> > down metering instead of having to use open aperture? > > >>Just a silly question, and forgive my ignorance, but why would you >>want > > to? > > >
