Originally posted by stevebrot To put everything in actual (degrees of arc) rather than relative units...
Diagonal FOV 50mm at infinity corrected by magnification and format
K-3 (APS-C) = 32.2° * 0.95 = 30.6°
K-1 (24x36) = 46.8° * 0.7 = 32.8°
5DM3 (24x36) = 46.8° * 0.71 = 33.2°
A900 (24x36) = 46.8° * 0.74 = 34.6°
Difference (A900 - K-3) = 4.0° (+12%)
Difference (K-1 - K-3) = 2.2° (+ 7%)
Difference (A900 - K-1) = 1.8° (+5%)
Difference (A900 - 5DM3) = 1.4° (+4%)
Difference (5DM3 - K-1) = 0.4° (+1%)
Thanks Steve, this makes more sense and gives a better perspective how the viewfinder sizes differs.
And if we were to continue going up in viewfinder size for full frame camera that's currently in production:
Canon 1DX/1DX II (0.76x Magnification OVF) 24x36= 46.8° * 0.76 = 35.6°
Sony A7R II/A7S II (0.78x Magnification EVF) 24x36= 46.8° * 0.78 = 36.5°
Leica SL (0.8x Magnification EVF) 24x36= 46.8° * 0.8 = 37.4°
Difference (1DX/1DX II - K-3) = 5.0° (+16%)
Difference (1DX/1DX II - K-1) = 2.8° (+ 8.5%)
Difference (A7R II/A7S II - K-3) = 5.9° (+19%)
Difference (A7R II/ A7S II - K1) = 3.7° (+11%)
Difference ( SL - K-3) = 6.8° (+22%)
Difference ( SL - K-1) = 4.6° (+14%)
Honestly though from personal experience trying a 0.7x viewfinder (Nikon D800) vs 0.71x viewfinder(Canon 5D3) I can't notice any difference, but both comparing to the K-5II I use to have there is a massive difference. I only noticed difference comparing the viewfinder of 1DX with 5D3 and A900 with 5D3.
The K-1's viewfinder is the same size as D800's and honestly it is pretty big already, just there are cameras out there there with bigger viewfinders... and those cameras with bigger view finders cost lot more than the K-1( A900 aside, that is an old camera. Especially the Leica SL, you can buy a whole set of Pentax gear with that price), the biggest viewfinder for current production cameras are EVFs, some people like them and some don't them(I like them both personally ) so that's another thing.
And lastly a simple viewfinder magnifier should make the K-1's viewfinder much bigger.