How many megapixels does film have? And I mean: for real, not the bazillion that the “experts” ascribe to it. The complete and yet unfulfilling answer is: depends. Mostly by ISO and by the format size, both of the film and the digital sensor.
Because two, for example, 12 megapixels sensors are not equal if one of it it is full frame and the other it’s the tiny tiny sensor of a camera phone. The rule of thumb, both in the analogue and in the digital word, is “the bigger the better”.
Those you find in the table below are my own findings, after over a decade of taking pictures. They are not results extrapolated by reading someone else opinion on some forum. So you may agree or disagree, but I’ll stick with my findings…
And by the way: even if a camera like a Canon 5D Mark II or a Nikon D3x (or better yet, if money are no object, a medium format digital back) it’s equal or better than film in most situations I STILL SHOOT (also) FILM.
Keep this in mind reading the results, because shooting film is more cumbersome, costly and time consuming, but has its unique advantages: it’s fun, it’s handy when if you don’t feel comfortable using a 2.000+ € electronic equipment under pouring rain, it has its look and it still yeld wondeful results in proper hands.
And some cameras like the magnificient Fuji GS645 or the Olympus XA serie (the review is coming) still don’t have a proper successor in the digital world.
For your convenience I have listed the results in the table below where you’ll find the format, the approximate diagonal size in cm (and I remind you that an inch is equal to 2,54cm) and a FEM (Film Equivalent Megapixels value) minimum, medium of maximum.
I have had to make this distinction because, for exemple, you may shoot with a crappy lens and shaky hands, or with the camera screwed directly onto a granite boulder (this actually it’s the setup to perform the MTF tests).
By the way, under “handheld” I collect all the non-optimal situations, like heavy wind, diffraction limited lenses, blurred images caused by photographer movement, blurred images caused by movements of the subjects (during long exposure time, for example), curved film, focus not spot on.
So you can interpretate the three levels as such:
MIN (handheld and / or scanning on a flatbed and / or high ISO) = calculate roughly 1,5 Megapixels for cm of format diagonal
MED (low ISO, tripod and / or scanning on Imacon and high-end scanners) = calculate roughly 1,85 Megapixels for cm of format diagonal
MAX (really low ISO, tripod, mirror lock up and scanning on a drum scanner) = calculate roughly 2,3 Megapixels for cm of format diagonal
|Format||Diagonal (in cm)||Min||Med||Max|
|4×5″ / 9x12cm||15,6||23||29||36|
|5×7″ / 13x18cm||22,2||33||41||55|
|8×10″ / 20x25cm||32||48||59||74|
And please, please, please take this results with a grain of salt: obviously you can go further with any format using special equipment, like shooting on ultra-low-iso-with-almost-no-grain-film and scanning on the SuperUltraMegaDrum @ 1.000.000ppi and so on. I made this reference table with an average user in mind…
UPDATE: please check the following two posts for a better and cheaper way to scan your films