Originally posted by IchabodCrane Call me the clueless one but what makes a Pentax pentaprism OVF better than a Nikon or Canon pentaprism OVF (sorry, I don't play with those other brands)?
In the low APS-C price range Pentax pentaprisms compete against pentamirrorrs. Pentaprisms are more heavy but very slightly brighter and very slightly sharper and less exposed to surface dust. Another difference is that Pentax have larger field of view, 100% image field coverage vs CaNikon 95% and larger magnification 0,92-0,95 vs CaNikon 0,82-0,85. Its not only more impressive to look through a Pentax viewfinder, but also easier to focus, gives better overview and more detailed view.
In the upper APS-C price range its more even with pentaprism vs pentaprism and more or less the same coverage and magnification: 100% coverage and 0,94 - 1,00x magnification for all dslr brands.
In the FF range we don't know what kind of OVF Pentax will offer yet, but Canon and Nikon offers OVF that is bigger then their high end APS-C cameras. 95-100% coverage pentaprism and 0,7 - 0,76 x magnification (Note, for APS-C the magnification should be divided by the crop factor to get comparable magnification numbers to FF. I.E. 1x magnification on APS-C equals 0,66..x magnification on FF)
In the MF range we don't have any CaNikon products to compare with, but Pentax offers 98% coverage and 0,62x magnification on both 645 D and Z. The magnification is sometimes referred to as 0,85x, but thats a 35mm FF equivalence.