Nope, comparing shutter speeds of 70/2.8 to shutter speeds of 35/1.8 is not helping at all.I didn't compare it specifically with 70mm, I compared it with a 24-70mm, because that was the comparison others made that started the debate.
While you should be comparing pictures/scenes shot with both and then presented on comparable mediums (screen or paper).
Otherwise the comparison is meaningless.
You seem to think that all that matters is the amount of light falling on a square micrometer of the sensor.If you read the thread, you'll understand that my objective was to dispel the notion that f/1.8 on APS-C is in effect the same as f/2.8 on full frame. That notion is actually an unhelpful
Just the opposite. The end result
is about the same, because it is mostly limited by purely optical
considerations. No matter what technical solutions are employed between the subject and the final image on paper or on monitor.
and circuitous way of saying that APS-C sensors are, because of their typically smaller pixels, usually noisier than full-frame sensors - simple as that.
Nope. They aren't noisier "because of their typically smaller pixels". Given the same size of the lens' entrance pupil (i.e. the same amount of light captured by the lens from an area on the subject), the same angle of view and enough of pixel well depth, they all will provide about the same amount of noise on the final medium.
They are noisier because the entrance pupils of their smaller lenses are generally smaller than on the lenses that provide the same angle of view for larger sensor formats. There are physical limitations in making large entrance pupils for smaller focal lengths, as pupils bigger than f/0.5 are impossible even theoretically.