> > I get correct exposed Velvia within 1/3s consistently for the > three labs I've been using. People expose Velvia at 40ISO because > the 1/3s stop difference make a difference. This differece > doesn't dissapear in processing or film variations. Pro labs are > extremely accurate. So are pro labs. But it doesn't matter if the > errors are consistent.
Thats just it. The errors are not consistant. The age of the film, the brand of chemistry, etc. are going to give random variations. > Shutters in modern cameras are 100%. False. All shutters have exposure errors, some worse than others. The fastest speeds are usually off more than the slower ones & in the direction of overexposure. And like I said before, even if you dont change speed, there are variations from one exposure to the next. > So is > metering calibration. Even a "perfect" TTL meter is only perfect when pointed at a 18% target. Rarely happens in real life. > Consistency is what it is all about. > Even if it wasn't, using metering accuracy that are worse than > 1/3s makes the exposure errors larger and make the results even > more unpredictable. I'm not arguing for worse metering accuracy, but what I'm trying to tell you is that even with a perfect TTL meter, there are many other real sources of exposure error that will prevent you from getting within 1/3 stop of perfect exposure all the time. > I don't brackett in order to accidentally hit the right exposure. > I bracket to have alternative exposures that might or might not work. > > Pål Exposure bracketing is nothing more than insurance against all the exposure errors present in the system. I wouldnt characterize it as an accident. It's a proactive method of avoiding the exposure errors that are beyond your control regardless of how "good" of a photographer you are technically. JCO > > > > ----- Original Message ----- > From: "J. C. O'Connell" <[EMAIL PROTECTED]> > To: <[EMAIL PROTECTED]> > Sent: Monday, June 09, 2003 10:54 PM > Subject: RE: Exposure (WAS: Re: OK Survey time) > > > > First of all, you will rarely if ever get "perfect" > > exposures with any TTL metering system due to the > > way they only measure reflected light. > > > > Secondly, there are exposure errors that occur > > in shutters both from speed to speed as well > > as from exposure to exposure even when set on same > > speed. > > > > Thirdly, there are exposure errors in the aperture > > when changed from fstop to stop. This throws off > > the TTL metering when using open-aperture metering > > as it assumes perfectly accurate stopping down. > > Even if you use a hand held meter, the error will > > still occur due to aperture variations from perfect. > > > > Fourth, there are speed inconsistancies in a given > > film from batch to batch. > > > > Fifth, many times with slide film there is no > > "perfect" exposure, variations around what is > > theoretically perfect just give slightly different > > interpretations of the same scene. This is another > > reason why some people bracket, to make sure they > > get just what they want. > > > > I think your quest for "perfect" exposures on > > all rolls of slide film is unrealististic, impossible, and > > thankfully unnecessary with the prudent use of bracketing techniques.... > > > > JCO > > > > > > > -----Original Message----- > > > From: Pål Jensen [mailto:[EMAIL PROTECTED] > > > Sent: Monday, June 09, 2003 4:24 PM > > > To: [EMAIL PROTECTED] > > > Subject: Exposure (WAS: Re: OK Survey time) > > > > > > > > > Caveman wrote: > > > > > > > > > > Ahhgad. Here we have a measurbator. > > > > > > I haven't met single photographer who don't want to nail the > > > exposure dead on. I want consistent exposure and I want it > > > without wasting film. > > > It is OK to like the LX meter. It is OK to prefer it. But have > > > you actually extensive experience with matrix meters calibrated > > > for slide film? Or spotmetering for the tonality of various > > > colors? I've used the LX 22 years and know everything about it. > > > It cannot give the same precision the 645n or the MZ-S gives and > > > this is important for 99% of all serious amateurs and > > > professionals alike. > > > > > > > If I'm not too pushy: > > > > - how do you define what a perfectly accurate exposure is > > > > > > A perfect exposure is what I define as a perfect exposure. I want > > > that exposure within 1/3 of a stop so that I can get what I > > > define as perfect exposure every time. . > > > > > > > - how do you describe the effect of a 1/3 deviation from the above > > > > > > 1/3 stop deviation is clearly visible on film like Velvia. 1/2s > > > off on Velvia may ruin a shot. Thats why I want to have 1/3s accuracy. > > > You have obviously never received a roll of film with all > > > exposures wuthin 1/3s of the correct one. Neither have I with the > > > LX. The thing is about consistency. Not what exactly is correct > > > exposure. You may not want that precision. Thats fine by me. > > > > > > > > > Pål > > > > > > > > >
