JCO wrote:
Now we see what your real definition of "perfect" exposure is, just make everything you point the camera at medium gray regardless of what it is in a real life scene. Absurd. REPLY: I didn't say that. You don't understand what I'm saying. Maybe because you don't fully grasp how modern metering work or how you use modern cameras for metering and exposure? I have pasted in what I really said for your convenience below. Look at what you said below. Even assuming "100%" accuracy in METERS AND SHUTTERS which is definitely not true, but just the tolerance errors YOU listed (unproven and which I still disagree with): REPLY: You dsisagree because you have no idea. You havent tried modern equipment. So you don't know what results it can provide. Your opinion is utter worthless. JCO: As for velvia, being "screaming obvious" different to a 1/3 stop exposure difference, I don't use it but if it was that sensitive, it would have an exposure latitude of something like +/- 1/6 stops which would be so narrow to make it unworthy of my consideration. I doubt FUJI would even market a film that prone to disaster. REPLY: So you haven't used Velvia either so you don't know anything about the film as well. Why are you arguing. Are we supposed that adhere to your belief system even if experience tells otherwise? Discussing beliefs are futile. Your statements are asthonishing in their ignorance for anyone serious about shooting slides. Not to mention those who do it for a living. Pål ------------------------------ > -----Original Message----- > From: Pål Jensen [mailto:[EMAIL PROTECTED] > Sent: Thursday, June 12, 2003 9:56 AM > To: [EMAIL PROTECTED] > Subject: Re: Exposure > > > From: "J. C. O'Connell" <[EMAIL PROTECTED]> > Subject: RE: Exposure (WAS: Re: OK Survey time) > > > Weve been down this road before, unless your > aiming your camera at a full screen 18% reflectance > subject the meter will over or under expose > the subject. the only way you could be accurate > is if you manually compensated the meter reading > based on the KNOWN reflectance of the subject and > that is nearly always UNKNOWN. > > > REPLY: > > Arrgh! This is not about autoexposure but metering which > something entirely different. It is about being able to set > metering within 1/3 of a stop. Known reflectance has nothing to > do with it. What matter for a photographer is tonality on FILM. > Ansel Adams didn't worry about known reflectance but the tonality > of the various part of the scene on film. It is exactly the same > principle with slidefim just the difference that developing for > all practical purposes is a constant and not something that can > be used to adjust the contrast range. Have you seen an Ansel > Adams print. Do you really think that whats medium toned on the > print was medium toned in real life? Maybe maybe not (most likely > not) but who cares and does it matter? > If I meter a medium toned piece of rock it is totally unimportant > if the rock is medium toned or not in reality. If I want it > medium toned I expose it as such, which is 0, it doesn't matter > if the rock is really white or black - it will be medium toned on > the film. If I want it + 1/3 I do that. If I want it as > silhouttte I expose it at -2. I don't care if the green grass > over there is really 0, -1/3, +1/3, -0.5 or whatever. What I do > want is to render it on film at +1/3 (with Velvia) because thats > nice in my opinion, and I get that with precision every damed time. > I also want to asses the contrast range of the scene fast and > with precision. I can do that as well. This will tell me how all > parts of the scene falls in the tonality range if I expose for > this or that. Say theres a patch of snow in the picture I don't > want to burn out. I need to expose it at +1,7. How then will the > tonality of the snow-free foreground turn out? Is the image > possible at all? I can figure this out in seconds because I have > that tool to nail it. If I expose snow at +1,7 it always get +1,7 > on film; never +2 which ruins the shot. I can promptly figure out > the contrast range between the forground and the sky. Do I need a > graduated Nd filter? How many stops? > These are the reasons why I want ot be able to nail exposure > within 1/3 of a stop fast and efficiently. > > - Pro slide film are within 1/6s tolerance. That is a worst case > scenario; they are practically speaking dead on. > Amateur slide film are within 1/3s but in reality amateur film is > exactly the same film as the pro version but is released earlier > to the store so that the manufacturer cannot guarantee its > history. Whatever differences this may make it is usually in > subtle colour balance, not exposure. > - Pro Labs are within 1/6 stops > - Modern Pentax lenses have apertures calibrated within 1/10s > accuracy. Canon claim 1/12s for the L lenses. > - All slr camera made after approximately 1985 have 100% shutter > accuracy. This have made the once common camera shutter tests > redundant. Even on older, less precise cameras the errors are > usually only significant in the real short speeds. > - All Pentax cameras I've bought since the 90's have 100% correct > calibrated meters right out of the box. In the old days, pre > 1990, a how to photography books would tell you to calibrate you > meter. They don't anymore as new camera bodies are usually dead > on. This usually no real problem as this is usually a constant > and any erors can be calibrated away. > > All the errors above don't really add up to anything significant > unless faulty equipment is at play or an accident happens. They > are too small to be of any concern and they are more likely to > cancel each other out than to add to each other. > I've shot several side by side test images where I compare > various Pentax 645 lenses. I shoot at various apertures and > varios zoom setting with various lenses. There are no exposure > differences regardless on Velvia. On this film 1/3s is screaming > obvious. Whats annoying with this futile discussion is that some > in reality are claiming that those of us who do nail the exposure > we want within 1/3s are lying bastards. It is somehow not > surpising that these allegation comes from people who use very > old equipment. That probably explains it all. I cannot nail > exposure this accurat with my older cameras. > Life is really too short for these futile discussions. > > Pål
