> > From: [EMAIL PROTECTED] > Date: 2005/11/17 Thu PM 02:31:03 GMT > To: [email protected] > Subject: Re: Manual focus screen > > In a message dated 11/17/2005 4:19:55 AM Pacific Standard Time, > [EMAIL PROTECTED] writes: > Yes, I believe they're referring to the scribed squares on some > models' viewfinders' screens. The blinky lights should still work. > > The bigger concern would be how much it messes with metering... in > particular spot metering. Different models will likely have different > amount of sensitivity. > > What I'd like to see is the ability to spot-meter at different > spots.... say a selectable corner? That would fix a lot of the metering > problems since center-weighted and matrix aren't as sensitive to one > sensor being off. Is that possible, or is the center sensor different > somehow so it allows spot metering? > > -Cory > =========== > Okay, there is some mention of metering on one web page. > > But I am clueless, why should it mess with metering? > > Marnie aka Doe
Because, in many cameras of this type, the metering cell is in the prism. It will be calibrated for the difference in light falling on the film (x) and the light passing through the extra bits like focussing screens and other bits of glass/plastic (x-) If you change one of those pieces, x remains the same but x- will possibly be different. Therefore the calibration will not work and you will get a different exposure value. It will usually be constant, so you can dial in exposure compensation to, er, compensate. m ----------------------------------------- Email sent from www.ntlworld.com Virus-checked using McAfee(R) Software Visit www.ntlworld.com/security for more information
