This has been the tendency of some posts around here... I've been crunching some numbers over the weekend, working from the other end, i.e. what is the biological resolution limit.
It is well-known that if a negative is good enough for A4 it is good enough for any enlargement, as the viewing distance will increase with the print size, making the net result about equal.
I postulated a 75x50 cm print, viewed at 75 cm distance. That would even tax film.
The finest detail the human eye can resove at that distance, for a relatively young person of say, 25 years old, is 0,25 mm.
We need, then, 4 points per mm. That makes 3000x2000 points, which is, obviously, 6 Mp. So 10Mp has plenty of reserve.
How does that compare to film? Well, normal 100 ISO slide-film resolves about 50 points/mm at 30% contrast transmission. That is just 1800x1200 pixels = 2.6 MP !!
Let's make the competition stiffer, use Technical Pan or Delta 100.
Those will resolve, used with an Apo-Summicron 90mm about 100 point/mm@ 30%.
Now we are talking! That means 3600x2400 pixels. Nearly 9 Mp. Very close to Leica's 10 Mp. But we needed the finest film and the best lens in the world to get that close.
But wouldn't more Mp's carry the M8 into the realm of medium format camera's? Not with a 1.33 crop sensor. The resolving power of the lens is, at 10Mp with a 1.33 crop, or 16 Mp with a 35 mm sensor, exactly the same as the sensors.So any increase in the number of pixels would necessarily involve reduction of the size. The only result would be that the same point projected by the lens would be picked up by more than one pixel, not creating any increase in resolution.
In terms of resolution sensors and lenses have reached the boundary of biological need. If we find one that we are happy with in terms of colour rendition, contrast and dynamic range, the only reason to"upgrade" will be mechanical, not electronic.
There is a myth that sensors do not have the dynamic range of film. That may still be true of the softest B&W film, provided they are developed accordingly, or with small second-rate sensors. In normal use however, a high-end sensor will render about 10 stops, which just happens to be the same as the number of zones in Ansel Adams' time-honoured zone-system. There is no way a normal slide film can better that.
There remains the issue of sensor noise. For one part I cannot understand that we accept grain in film as normal or even desirable, and will not grant sensors the same courtesy, on the other side sound engineers have been fighting noise for decades now, with some result, but it seems to have levelled out. I doubt there is much to be gained in that department.
Is this the death-knell of film then? I don't think so. There are - and always will be - artistic differences between the two media. I spent a lovely weekend listening to vinyl records - yes they sound nicer, albeit less perfect than a CD and they are still available, as are turn-tables and cartriges and tube amplifiers, and my daily car has been pushed into second place by my TR4 these summer days, which, even if cars have evolved dramatically the last 40 years, drives as well, but with more character. Morgans are still being sold.
Will the M8 turn into a vintage digital camera over the years? It seems to be fairly certain.
