Kalart Focuspot laser pointer retrofit

[Ivan J. Eberle]

I've got a Kalart Synchronized RF that I've re-mirrored and and adjusted so it's working with extreme accuracy. Comfirmed focus with a laser pointer, and I'm now stoked with the idea of replacing the bulb in the Focuspot with a small keychain-type red LED pointer to use it even in broad daylight. However, with the rotating back on my Meridian, it also needs to be configured as closely as possible original (no mounting on the eyepiece, for instance). Haven't been able to find any good laser pointers locally despite much running around.

So, what specific model laser fits inside the Focuspot housing and/or what did you end up doing for your hack?

[Ulrich Drolshagen]

In Germany there are online-shops for electronics parts like conrad or reichelt-elektronik which sell the laserdiods. I am sure you will find such shops in the US too.
I am very interested how you swapped the mirror. I found a source for half transparent mirrors but they are slightly thinner than the original one. How did you get the precision in remounting the new mirror?

Ulrich

[Ivan J. Eberle]

Ulrich, the mirror is semi-silvered on the first surface. I figured that it would work if the new mirror surface was in the original plane. I used a thin strip of wood installed toward the back side of the U-shaped channel to shim the new thinner glass piece forward. (I split and shaved down a wooden matchstick with a razorblade and, keeping with the character of the period, glued the mirror in place with Duco Cement. But don't do as I then did by trying to calibrate the RF right away: air-drying cement set up quickly but changed the focus ever so slightly and maddeningly over the next several days.).

Getting the plane of focus perfect with the mirror mounting may not be as critical with the Kalart Synchronized RF as with other types, since there are several points of adjustment on the Kalart.

The most crucial thing in mounting the mirror is being sure the first surface is the silvered one--or you'll get a double image that will never properly resolve into just one image when adjusting focus.

[Ulrich Drolshagen]

Thank you Ivan. This is encouraging me to do the swap an mine as well.

Ulrich

[ki6mf]

Please keep posing any information or links you find on this subject!

[towolf]

I found a laser pointer that works perfectly for this. Here’s my report.

[Tin Can]

I'm going to try it. I ordered this which should fit right inside a FocuSpot and then wire it to my Graflite flash handle.

http://www.amazon.com/gp/product/B00...?ie=UTF8&psc=1

[Will Frostmill]

I can't wait to see what you guys come up with. I bought a pair of Kalart's with one focuspot attachment years ago, with the intent of doing something like this. I acutally had in mind using a conventional super-bright white LED for this, but I'm not sure how well it would work.

[BetterSense]

Please be careful and never use this toward people. I would go so far as to suggest that you label the camera to the effect.

[Tin Can]

Yes, it is dangerous to point lasers at people, especially the eyes. What if they shoot back? I plan to use mine at night in the woods and without people, but if careful one could focus on the chest of a person.

Last night I tried a LED Fenix tiny flashlight that fits inside a FocuSpot, but it doesn't not work, as the beam is too diffuse, even with a 1/8" aperture on the lens.

The OEM FocuSpot bulb works well because we only see the actual filament and the RF allows us to align, or coincide the 2 filaments projected. Easier to demo than write about.

Of course all this depends on a properly calibrated KalArt RF that we have verified on GG, so we can trust the RF in the field.