blue9 wrote in post #16697360
the 2003/2012 case is a special case, but i mention it because i think sensor size and type should be left out in the equation. By that i mean for me it's easier to compare a 100/2.8 with a 200/2.8 and just keep in back in my head that if the photographer with the full frame sensor is as new as the smaller m4/3, he can get the same result with a f5.6 lens.
This is not a new problem.
I shoot a lot of medium format film. My standard lens is an 80 f/4 on 6x7 film, which has a little over 4x the area of FF 35mm (digital or film). So that 80mm is really about 35-40mm (it's not exact, since the aspect ratios aren't the same) on FF, and f/4 gives me the equivalent of about f/1.8 DoF on FF.
Similarly, a "normal" lens on 4x5 film is about 150mm. In large format, f/5.6 is fast.
Of course, when it comes to exposure, f/4 is still f/4, irrespective of sensor/film format.