[polarhki]

If you have read the first passage you will actually notice that I emphasized that the primary differentiator of the system is size and weight.

 

Just as a reminder - Olympus has released the 12-40/2.8 and will release a 7-14/2.8, 40-150/2.8 and 300/4. These lenses are all directly competing with APS-C counterparts - based on a sensor that it simply a bit weaker.

 

Ok, acknowledged. If you look at rather wide angle lenses, then of course the argument about small-size and low-weight becomes less relevant. However, there is another point not to be forgotten: If you compare, for instance, the Olympus 12-40/2.8 vs the Zeiss/Sony 16-70/4, as you mention above, the Olympus is a f2.8, and the Zeiss/Sony is a f4. I know, depth-of-field is similar, and the total light gathered, too. But the light gathered per sensor area is anyway larger for a f2.8 than for a f4 lens, by definition. Meaning that in case the sensor is equally sensitive in both cases, it allows you shorter exposure times at the same ISO with the f2.8 lens (or lower ISO with the same exposure time). - Or do I miss something here?