Mostly a picture gallery right now, but here is a brief description of what it is all about:
The intention is to have a high brightness, colour controlled lighting system to allow fast "on-the-fly" tuning of colour balance and exposure. I have built 5 versions of LED assemblies and am now working on a second version of controller.
The latest version does not vary the intensity of light, but rather the exposure time of each colour channel and is designed to work with triggerable cameras, such as the Guppy mentioned eleswhere on the site.
For use with colour cameras, the unit will use White, Red, Blue and Green LEDs. For monochrome cameras, it is possible to fire sequential colours (R, G & B) for capturing separate mono frames which can then be combined into a high resolution colour image in post.
One reason to use short, bright exposures (targetting around 1ms) is to keep the on-time of the LEDs to a minimum and hence mostly eliminate the colour drift problems caused by LED light output dropping with increasing die temperature. Unfortuately, the drift varies with colour, with the red LEDs dropping in output at nearly twice the rate of the blues and greens.
Another benefit to short exposures is of course less sensitivity to mechanical system vibrations and film creep in the gate.
On with the pictures...starting with the latest and greatest and then going back to the earlier attempts.
30 LED system built onto MCPCB material...my first go at using this metal-backed PCB product! The Rebels sit well within a circle diameter of 35mm:
some shots of the "production" process:
LEDs applied with tweezers, they self align when flow-soldered. I did this by placing the assembly on an upturned domestic iron:
The Mk2 control system, currently in development:
Mk4 and Mk3 systems. These were similar and based on commercial "Star" bases made from MCPCB, each able to take 3 Rebel LEDs:
These heatsinks looked good but didn't perform well:
An even earlier version:
A crude light mixing assembly for the Mk4 built into the Eumig 610D:
The Mk1 control system:
