[Tig] camera dynamic range quotes are getting silly!

Richard Kirk richard at filmlight.ltd.uk
Fri Mar 4 23:03:35 GMT 2011


> peter_swinson at compuserve.com
>
> If I wanted to compete with the mega stops range, but with film, and  
> avoid the different movement artefacts with multiple shutter rates  
> per frame, I reckon here is the solution.
>
> Take one Technicolor 3 stripe camera, remove the color beam  
> splitter, replace with a semi silvered splitter. Use three color neg  
> stocks, 1 very fast, one medium, one very slow.  Shoot, process,  
> scan and then combine the results.

Not entirely silly. There used to be a three-layer black and white  
film with three emulsions, each with 100th of the sensitivity of the  
level above. This was used in the 1950's and probably 60's to  
photograph surface nuclear tests. As  usual, the contrast range was  
probably limited by flare, but the need was to cover a rapidly  
changing image brightness when an automatic iris could not ber fast  
enough.

The better solution would be to have a detector and electrowetting  
display a bit off the focal plane. This could reflect light from the  
bright regions and let it through in the dark regions. If the  
electrowetting display used mercury, it could reflect the light back  
out of the front lens, so it did not add to the flare in the camera.  
This assembly would not have to be as high resolution as the actual  
detector if it was off the focal plane.

You could have a similar plate that worked the other way around for  
projectors.

Cheers.
Richard Kirk




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