True Resolution of film

[larkis]

I ran across this

video on youtube and was fascinated by it for a couple of reasons. It seems to throw around a bunch of numbers that seem factual, but arrives at a crack pot conclusion, easily debunked by anyone with eyes. The video seems to follow the same playbook as a lot of medical quackery videos/articles online.

I would be curious if one of the more engineering focused members could point out where the big mistake in interpreting the data is happening. As someone who has shot and developed film for years, I understand the hipster and gen-z draw towards something "magical" of the past, but for me the reason to shoot film has nothing to do with its resolution characteristics, especially not in the 35mm format.

 

[MGrayson]

To me, the biggest howler is the persistent use of the 1000:1 contrast ratio lp/mm number. Can you imagine an image where EVERY pair of adjacent pixels has a 10-stop brightness difference? I'd bet the usual number is 1.01 (just a second - I'll do a measurement... Huh. First image I tried gave 1.007 - lucky guess).
Now 1000 and 1.007 are wildly different numbers (17 stops different). The other quoted number was, I believe for 1.6 contrast ratio of adjacent line pairs. That number was about 1/3 to 1/4 of the 1000:1 number, and that would cut his pixels calculations by 4 to 9.

So 8x10 film being a few hundred MP? Absolutely. IF every pair of adjacent pixels has a 1.6 contrast ratio. See the 1.007 number above.

That's my take. I'm sure those more knowledgable will have better answers.

Matt

Ok, a more honest calculation, as only a few places need to be sharp to look sharp - it's not the average contrast that really matters. So in my random test image, only one pixel (out of 65,000,000) had a contrast ratio > 1000. Ten thousand of them (1 in 6,500) had a contrast ratio > 1.6. No, I don't know what this all means.

 

[Duff photographer]

The video seems generally legit. He over-emphasises a few things like contrast and that 800 lp/mm large format film would outperform everything - it would if it existed and had the lens that could convey that resolution to the film (that too, doesn't exist), but does balance out the theoretical resolution with practical resolution, by listing all the issues that reduce resolution; something which also applies to digital.

What he says about Adox is fine too. I have seen a 6 foot print from, I think Gigabit 35mm, which was effectively grainless as I recall. I can't remember how "sharp" it was as it was just before digital came in, but it looked fine to me with regard to resolution, i.e., there was a lot of detail on show and the film was out-performing the lens with regard to resolution.

There are aspects where digital is better than film and film is better than digital. Neither one is "better" than the other, as all these aspects meld into one to produce the final image. They're just different in many cases and these differences will be favoured by different photographers.

However, it was a pointless video as are all videos trying to determine which system has the better wotsit or the highest thingy. Film and digital can all produce resolution beyond that required by most people. What matters is the photograph itself, and the ability of the photographer to not just see the shot, but to take it too. Quite often the latest craze, such as high pixel count, high resolution, or high contrast, count for nothing. (Okay, personally I do like high resolution images generally, but you get my drift).


Cheers,
Duff.