Quote:Well, the only person deciding which is lowlight and which is DoF centric, is you, Klaus. I say, DoF is by far less important than speed of a lens. DoF is nothing to be used with some precision. if I want everything sharp from that stone to a branch 65 cm behind the stone - and I want it really sharp and not just sort of less blurry than the rest of the picture; i have to go either Scheimpflug or focusstacking, everything else I see as cooking fog.
Speed = max. f-stop correlated with acceptable sensor noise
Whether I shoot
f/2.8 at 1/500sec @ ISO 400 (APS-C)
f/4 at 1/500sec @ ISO 800 (Full format)
is utterly irrelevant. The SPEED is 1/500sec in both cases. The result is the SAME (assuming the identical field of view, a perfect lens and comparable megapixels).
The speed of the lens alone is meaningless. A lens alone doesn't take pictures. I can have a look through the lens with my naked eye and enjoy (?) the "original" speed of the naked lens. That's it. What use case is that ?
The system of camera + lens (+ human) takes pictures.