Tuesday, June 13, 2006
The other day while I was out strolling, my family and I came upon a broken and discarded projection tv. I was pointing out the various parts of it and what they do when I realized "Hey, these three projection lenses are 2.5/3 intact!".
I wrote down the address of the place and came back later with tools. I had no idea what to do with them at the time, but figured 5-1/4" lenses would lend themselves to something. They seem to project well when a strongly lit (from behind) image is placed flat on the rear lense.
I looked up the lens on the net, and the first link was to an astronomical satellite proposal (powerpoint format) describing an orbiting composite x-ray telescope(s) that would be able to directly image black holes ("The Field of View of a Thin Lens Interferometer"). It's coincidental, but not related to the reported research I mentioned in I want Black Holes for Christmas! a couple of weeks back.
The X-ray satellite project made me think "Hey! They could concentrate light for my digital camera!". I tried it. I liked it.
There are some artefacts in the image (blue near centre, reflections, spectral abberation on the right side), but I didn't spend much time eliminating problems. This particular image was taken by hand-distancing the camera lense from the projection tv lense (i.e. poor focus stability). It sure grabbed more light. I think next I must make a jig to hold a camera at the right distance to the lense and take some starfield photos with my new five-incher!
Sexy photos to follow.
Burton MacKenZie www.burtonmackenzie.com