Originally posted by Pompous Moronox This is false
A 200/2.8 lens for this hypotethical tiny sensor camera would still be rather large, not really much at all smaller than the current "regular" 200/2.8s.
However, to match that camera/lens FOV and DOF performance on a FF camera one would need a 1120/16 lens which would not be much bigger, and would be quite a bit cheaper to make - the 1120/16 would be a very easy design, no exotic materials needed and it'd likely deliver higher quality image than the more agressive 200/2.8.
Originally posted by Pompous Moronox Wrong.
If we have a FF camera with f/2.8 lens and a NC-1 camera with f/2.8 lens, the FF camera will collect about 30 times or so more light. So if you stop the FF down too about f/16, you'll get about the same amount of photons you'll get with a NC-1 with a f/2.8 lens.
Yes, you are correct about the photenes. But, if we have a FF camera with f/2.8 lens and a NC-1 camera with f/2.8 lens and both lenses has the same FOV, we have the
exact same shutter speed @ ISO 100, for example. So, if we stop down our FF lens to f/16 we will get about 4 stops slower shutter speed on the FF then on the NC-1. Now we have to rise the ISO on the FF to 1600, in order to get a decent shutter speed. Whoops, we just lost the advantage of the large FF sensor, we have now the same FOV, the same DOF and the same noise.
And why would I be interested to buy a ~1120/16? Sure, it might be cheap and small as a 200/2.8. But,
no camera will AF with such a slow lens and the view finder will be dark as a cave, so no accurate MF either.