[Laser] Reflex film camera on the receiving end

[Paolo Cravero]

Hello!
After playing with simple and modern hardware on 10 GHz, a group of
Italians has started fiddling with optical communications. Three of us are
lucky enough to live within ~10 km in LOS (not me). The philosophy of our
experiments (games?) is to keep everything as simple and cheap as possible,
while offering opportunities to learn new things. Our optical sensors are
common OPTxxx or BPW34 photodiodes, nothing fancier. TX side is a matrix of
LEDs or toy laser pointer (those that work on button batteries).

We've been discussing and trying Fresnel lenses, with inherent
complications in mounting and handling size. Then in a video of Norwegian
HAMs using a German WW2 device for optical communication I noticed that
their "antennas" made everything look like a large binocular (and boxes of
equipment behind :) ).

So I remembered my unused reflex film camera and imagined how comfortable
it would be to use a compact, self-contained device that only needs the
optical sensor to be put in place of the film frame. I browsed through the
list archives (subjects, not all message bodies!) and I haven't found a
similar conversion, so either it doesn't work or back-then reflex cameras
were too expensive for this kind of game.

Today with 40-50€ you can buy a film camera body and simple zoom optics, if
you haven't got one laying around.

I can mount it on a tripod right away, it doesn't look suspicious, it isn't
bulky to carry: where's the catch, Sirs? Does a 50-80mm focal length lens
perform as good as a 20x25cm Fresnel lens?

Thank you for sharing your thoughts,
Paolo
...heading down to the storage room to dig the old Canon 3000N.