For example: Say his lens is consistently f8 at f8 setting. same lens is consistently f16 at f11 setting (over exaggeration).
The meter assumes both are perfect and assigns 1/125 for the F8 setting, 1/60 for the F11 setting. THIS IS THE MAIN FLAW OF OPEN APERTURE METERING. It doesn't take the real f-stop into account. RESULT the two exposures are not within 1/3 stop at all settings, even though they are consistent errors. JCO > -----Original Message----- > From: William Robb [mailto:[EMAIL PROTECTED] > Sent: Thursday, June 12, 2003 11:12 AM > To: [EMAIL PROTECTED] > Subject: Re: Exposure > > > > ----- Original Message ----- > From: J. C. O'Connell > > > > > > I dont agree with your statement below that the cameras/lenses > > dont have to be very ACCURATE as well as consistent accross > > all settings to achieve 1/3 stop exposure accuracy > > under ALL conditions like he claims. > > As long as they are consistent, what else matters? > In my black and white work, by the time I have arrived at a working ISO > for a film, I am generally a stop and a half slower than what Ilford > says the film speed is. > Whether this makes my equipment inaccurate by a stop and a half, or > whether it means I like more shadow detail than what Ilford thinks I > should like doesn't matter. > All that matters is that the equipment behaves in a consistent and > repeatable manner. > > William Robb > >
