I'll put it another way-
If I set the 10-18 zoom to 12mm, the focal length of the Samyang (which is an APC-S lens - correction!), on the A6000 the FOV is smaller than on the A7R.
My "18mm" comment is the setting which makes the FOV with this zoom on the A7 to same as 12 mm on the A6000 - the FOV with a given focal length is always smaller, i.e. the lens is longer, on APC-S cameras than on FF cameras. After all, the sensor is smaller. All these lenses are defined on the same basis, even if APC-S lenses are smaller.
Or, put the other way, a given lens will be wider on FF than on APC-S because more of the lens's FOV is used (not talking about vignetting with APC-S lenses, which complicates the issue - unusually, the Sony 10-18 fills the FF sensor at most focal lengths).
I think this is the easiest way to think about it. Unless I have made some inexplicable mistake.
Last edited by artHarris
on Sun Feb 22, 2015 9:19 am, edited 1 time in total.
Kit: all Sony now:
RX-100/3, A6000, A7R. Lenses:FE16-35, FE24-70, SonyF10-18,SonyF18-200, FE35/f2.8, F16/2.8, Minolta APO 100-300, Nikon 135 macro, Nikon 50/1.4, various extras.