Concurrent photon amplification - does anyone make a cinema camera with this mechanism?

[Karim D. Ghantous]

Some years ago I came across an old technique called 'concurrent photon amplification'. It was, I think, only used in photographic cameras, such as a Leica M4. There was one such camera on eBay a few years ago.

Recently I got to thinking about it again. I was reminded of it because of recent news that Kodak ditched their plans to make a 1000T stock. This 1000T stock was apparently no better than 500T pushed. So, I thought: wait a minute, maybe CPA can do a better job here.

This thesis is worth a glance. Sadly, I do not understand the equations, although this isn't expected of photographers.

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FILM SPEED
Because fewer photons are needed during the imaging exposure, there is an apparent film speed increase. Speed increases of six stops have been reported using Tri-X Pan emulsion. This represents a very significant enhancement but begs the question: What effect does CPA have on image quality? One answer is obvious, if there is an image where there was none before, there is an improvement in image quality.

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CONCLUSIONS
In summary three distinct conclusions can be drawn from this study which represent the assertion of the initial hypothesis. There are:

1. There is a low exposure domain in which only CPA can give an image. The size of that domain is a function of the means of measure. For a quantitative measure, the size is modest, only one stop in this study. However if a subjective measure is employed, that CPA domain of preference could be larger, as much as six stops.

2. There is a domain where both CPA and normal exposure will produce an image and in this domain, CPA will give a better image than normal exposure. The benefit of CPA diminishes towards the high end of this transition domain.

3. Above the transition domain, normal exposure will yield a better image than the CPA treated image.

So, subjectively, according to the conclusion, 5219 (500T) stock could have the sensitivity value of up to ASA 32,000. (Whereas a 400 speed photo film, such as HP5+, could be rated at up to 25,600). This sounds too good to be true. However, I will point out two things: firstly, I have not tested CPA; and secondly, the fact that digital cameras can function at ISO 32,000 is also "too good to be true."

Also worth exploring are potentially different effects on both colour and b&w stocks.

At worst, and in theory, 5219 gains one stop without pushing, and without any penalty. And 5203 (50D) can now be rated at ASA 100, which is no bad thing.

[David Mullen ASC]

It's just another form of flashing or latensification. And yes, there are on-camera flashing devices (Panaflasher, ARRI Varicon, etc.) The claims of increased sensitivity have always been a bit exaggerated.

 

[Karim D. Ghantous]

15 hours ago, David Mullen ASC said:

It's just another form of flashing or latensification. And yes, there are on-camera flashing devices (Panaflasher, ARRI Varicon, etc.) The claims of increased sensitivity have always been a bit exaggerated.

 

Those aren't the same thing. The Varicon is placed in front of the lens. It has its uses, and I understand those quite well. But it's not the same thing at all.