Originally posted by gazonk An APS-C camera needs to have a larger than 1.0x viewfinder to match the viewfinder of an FF camera.
You're so right.
My MX is 0.97x 95% and my K20D is 0.95x 95%. Looks close.
But in reality, because of the crop factor, the K20D is only
0.62x @ 95%! The focussing screen looks MUCH smaller.
It would have to be 1.48x 95% to match the MX. This is so because magnification is measured at 50mm. So, 1.48x@50mm becomes 0.97x@33mm.
A 0.75x magnification which once was considered to be the minimum to be accepted at 100% is 1.15x for APS-C.
What Art Vandelay II and gazonk said.
True, a 1.48x focussing screen would be dimmer. But at a given physical aperture in mm and a given FoV, an APS-C lens would have a smaller f-stop figure to compensate for exactly!
It is the cheaper (smaller) APS-C lenses making the viewfinder dimmer and the smaller magnification obfuscates this fact from the consumer.
A pro camera (even APS-C) should be made for larger lenses and have higher magnification. Theoretically, the eye piece could be replaceable to make this property adjustable.
Last edited by falconeye; 04-21-2009 at 08:04 AM.