[mikewhy]

> the Rittenhouse trial and the big to do about the video being enhanced when zoomed

I keep thinking about this, and was already when the case was going on. If linear interpolated zoom isn't allowed, no iPhone photo after a certain time should be.

[mateo1]

Well, it appears that we are rapidly approaching the point in time when these companies are no longer going to be able to deceive consumers like this. After that there will be an off button and perhaps legally mandated metadata, although I'm sure forensics people can already tell when AI trickery has been applied.

[wmf]

If linear interpolated zoom isn't allowed...

Think about analog/optical/chemical photography. In the old days did juries look at camera negatives with a loupe? Of course not, they looked at enlargements. What "algorithm" does an optical enlarger use?

[tagoregrtst]

Continuously linear implemented with an analog device vs digital “linear” (ie, watch your floats! Take care of quanization error! Have you kept the colors separated according to the Beyer pattern?).

No one has a problem with a mathematically perfect linear transformation, and film enlargers come very close to that ideal (yes they distort, but in a very obvious way and by degrading detail not adding detail that isn't there)

The analog picture is much harder doctor. More gracious artifacts in blow up (grains are random, versus sharp grid). Much more detail is recorded (by virtue of the size of the sensor and therefore the diffraction limit. Sensor resolution is not too useful).

[dagmx]

Film development is actually quite a bit more subjective. There's a much larger variance in film type, and the chemical process.

Perhaps it's harder to doctor, but it's also not necessarily truer either.

With regards to sensor size and detail recorded...well that depends. Are you assuming 35mm sensors? Because people shot 8mm and 16mm too back in the day. That's not far off from smaller sensors today. Are we also accounting for film sensitivity? Because digital sensors have far eclipsed the sensitivity range of most common film types now, so would be more likely to resolve image data.

It's not so cut and dry.

[tagoregrtst]

Sensitivity of digital is amazing. You cant really get past ISO 400 on film without large compromises.

But, as for size, photo cameras sporting film smaller than 35 were rare. Yes Kodak had the advantax (?) system and some other weird cameras here and there, but the vast majority of consumer pictures were taken on 35mm.

As to the subjectivity of film, as I mentioned in the other post, most of the subjectivity came from what I called the “z” dimension, i.e exposure. There was little subjectivity about the enlargement itself.

That is to say, the subjectivity was largely limited to the contrast and brightness sliders of today. Anything else is far more difficult to do with film.

There is another advantage for digital, cost. Video was much more rare with film, and the video we’re talking about certainly would not exist.

But I think that’s the greatest advantage of film - it contains within it an inherent protection of the public’s privacy completely absent in our society today

[dagmx]

Specifically, this thread originated with the Kyle Rittenhouse trial which would be video. So for the average person, it would be 8/16mm.

Even for stills, 110/126 was very common.

As for your last point, it only ensured privacy from the poor. Privacy was always invaded by those with means like paparazzi.

There's also the flip side that the prevalence of digital has let people capture pivotal moments they wouldn't have been able to otherwise, including generation defining moments like the murder of George Floyd.

[tagoregrtst]

Privacy for the poor, not from. Paparazzi have never been outside my door. They were taking pictures of rich people for gossip mags (ie poor consumers).

Now we spy on poor people, use AI to analyze the photos at scale, while the rich got anti-paparazzi laws put in places like EU and CA.

In this context, the Rittenhouse video would not exist and it would be better if it didn't. The prosecution, arguably, should get disbarred for the shenanigans they pulled (no discovery and dumping it in the last moment, giving a modified version, lying about the provenance).

As to George Floyd, cameras have done much more to erode our civil liberties than they have put bad cops away.

[djrogers]

> But, as for size, photo cameras sporting film smaller than 35 were rare.

Strong disagree here. 126 film is what brought color photography to the mass market, and others like the Kodak Disc were wildly popular among point-n-shoot users.

35mm was standard for pro photogs, but consumers went for convenience.

[djrogers]

I should also point out that while 126 popularized color photography, a decade later 110 came along and largely dominated consumer photography until the digital revolution.

[tagoregrtst]

126? 110 (other comment)? By that token betamax was a successful format in 1975 before VHS launched.

35mm was the top selling film since the 1960s until digital took over.

You went to any drugstore and you found 35mm. Maybe a box or two of APS. Maybe some medium format. But you could find 35mm in every drugstore, gas station, street vendor in a tourist trap without fail.

Professionals used 35mm because it was snaller than MF and for many things good enough. Otherwise it was considered consumer grade.

[sudosysgen]

Film development is actually VERY, VERY far from linear.

Because of film grain, it's not continuous either, but actually discrete too.

[tagoregrtst]

Film development is very non linear in the exposure (call it z dimension), not in the dimension (x and y). That is to say it might exaggerate or diminish a gradient that was already there but not create one from nothing.

The grain is random size and randomly distributed which cancels out a lot of the effects of discritzation (eg you wont get patterns due nyquist sampling error).

[sudosysgen]

It's non linear in the X and y dimension because of grain.

Any camera with a good antialiasing filter will also have little to no discretisation error.

[tagoregrtst]

Its non linear because enlarger optics are non linear.

The image of a digital or a film photo is a mosaic. This mosaic can be mathematically enlarged into a large mosaic. If you enlarge far enough you’ll see the individual tiles. This is a linear operation no matter the shape of the tile.

Digital photos do not, however, just make the tiles larger. They could but its not done.

Even before enlarging, they interpolate between tiles to recover color (each pixel in the sensor is monochromatic).

When a picture is displayed, the screen resolution is not that of the photo, so an algorithm has to fit one grid into another. And this is before going into superesoltion techniques.

But none of this would matter if we had a standard, open source, way to utilize digital photos in court. Until then Mr. lawyer can get himself an expert to testify to the validity of each and every still he wants to show the court.