Lighting control for optimum exposure

Hi all,

I’d love to somehow have a system similar to the Cine2Digits setup, but maybe just even white LEDs to begin with.

A big issue that causes a lot of frustration for me while scanning is the ability to quickly change exposure during scene changes.
I use the moviestuff universal II, but unfortunately the computer can’t tell the scanner anything.
The auto exposure just changes the gain level, but I’d much prefer to keep the gain at 0 whenever I can, and have the LED output changed by the computer.

So I sit there and manually exposure all scenes, keeping the gain on 0 if I can, and changing the LED dimmer via a pot. But I’m just not fast enough if the film was constantly changing outside>inside. I have to stop the capture, rewind, then continue on with the correct exposure.

I’m guessing the software would take the histogram output from spin view, and tell an external controller connected to the computer via USB to reduce the LED output by x value to keep the exposure from clipping.

Also using a strobe would be a heap better than constant illumination for heat saving.

The logic sounds simple enough, but I’m hopeless at programming.

Just thought I’d drop an update in here, I’ve given the moviestuff software a bit more of a chance and learnt some more.

I was wrong, it does increase the gain, but only after the exposure time has reached the maximum before the film movement would be visible. I think that’s around 220us.

I’m now using auto exposure more often with with LED on 100%, but moving the exposure compensation slider up and down as needed. a dark scene with someone with a white shirt on will blow out if I don’t adjust it quickly.

This is why I’d like software to have an adjustable ROI to ignore the open sprocket holes, and to measure independent pixel values to keep whites under clipping level, instead of the basic auto exposure built into the FLIR SDK.

I’m looking into ActiveUSB, which is made by A&B software who frank used to make his cine2digits software. apparently it’s easier to use, and it also has more inclusions like DPX output.

One could make their own timer circuit with a MOSFET to strobe the LED after receiving the trigger signal from the sprocket hole sensor.
I found a company called Gardasoft that makes lighting controllers for machine vision. I’ve bought one of their RT220 controllers from ebay to experiment with. My only concern is the LED and camera are being triggered at the same time, so the warm up time of the LED will be happening at the same time. Ideally I need to put a delay on the trigger to the camera.
Hopefully the moviestuff software doesn’t get confused by the strobing light. This might be a good upgrade for moviestuff owners to drop into their scanner if they find they are struggling with underexposed 8mm film. I’ll share how I go when it arrives here in Australia from the US.