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 (http://www.largeformatphotography.info/forum/showthread.php?115600-DIY-Kalart-FocuSpot-style-Laser-Ranging-with-Technika-RF).

[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/B00ANY8KPK/ref=oh_aui_detailpage_o00_s00?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.

[Jac@stafford.net]

The laser has a frequency of 650nm. Can you/we see that wavelength? Does it possibly entirely penetrate the half-silvered mirror so that nothing reflects from the rangefinder?

The Focuspot actually focuses an image of the conventional lightbulb's filament. I should think an LED at the point of the original bulb's filament would work better.

We shall see. My Linhof Super Technika V is one that has a Focuspot port. I've used it to some success.

[Tin Can]

The laser has a frequency of 650nm. Can you/we see that wavelength? Does it possibly entirely penetrate the half-silvered mirror so that nothing reflects from the rangefinder?

The Focuspot actually focuses an image of the conventional lightbulb's filament. I should think an LED at the point of the original bulb's filament would work better.

We shall see. My Linhof Super Technika V is one that has a Focuspot port. I've used it to some success.

I sure don't know the mirror and wavelength answer Jac. I did read somewhere on the great Web of confusion that some have re-mirrored the Kalart, possibly for this very issue.

The LED flashlight I used had a diffuser lens and it cast a 36" circle at 8 ft through the RF with a 6" center spot, that was difficult to align. I deemed it useless, but I tried.

A very tightly focused LED might work, but a laser point is exactly what I want. It will be here this week.

[towolf]

My Laser pointer is deep red (650nm sounds right) and it works perfectly on my Technika V.

[Tin Can]

I got the laser today. Made in Taiwan, a country that makes high quality goods. This is not junk, they enclosed their product line, military and scientific applications. Once again, buy cheaper and cry twice.

Sure enough it fits right inside a FocuSpot in place of the original bulb, with very little work. I wanted to use the original rotary switch, but disassembly mistakes stopped that. Maybe iteration 2 will have that function, the 1st version of anything is a learning process. I would prefer an OEM rear FocuSpot switch, so the red button could be used elsewhere... So I learned a bit and I'm not telling all as there is a valid concern that this is not a toy and a laser is dangerous when used improperly. There are 2 steps to completing this modification, the first is obvious, mount it inside. The second is the trick that makes it work. If you can do step 1, you will figure out step 2. Then be careful.

Installed in a calibrated Kalart FocuSpot this laser is usable past 100 feet under street lights at night. It also works at 3 feet. Very accurate as checked on GG. The first picture shown is taken with full power flash showing 2 spots. I plugged the power cord into a Graflite outlet controlled by the momentary red button as seen in the pictures. Push that button and focus. Then move your hand down and shoot with the 2X3 Crown body release.

131028131029131030131031

[Jac@stafford.net]

I must say, Randy, that is one classy build.
.

[goamules]

Very cool Randy. The first time I used the Focusspot, I was very excited. The laser makes it that much better.

[Ivan J. Eberle]

Nice build, Randy.
I found that a laser really speeds up the process of re-adjusting a Kalart (or resetting it to a specific lens) installed or even handheld and shone through the rangefinder eyepiece.
Also, while I won't stare at one or point it in anyone's eyes, I don't really believe typical red cat-toy LED lasers are very dangerous to eyes compared to other laser types, because they tend to be slightly diffuse or de-tuned. They'll work fine for this application even if slightly diffuse. (Some LED laser capsules have a collimation-tuning cap or thread, as well, and can be de-tuned.)

[goamules]

I used to teach laser safety. Only when you get to class IIIB lasers is there any danger to the retina for brief seconds of exposure. With the lower classes your blink reflex is enough to protect your eyes. If constant exposure of lower classes is for many seconds, it's possibly dangerous. Optics (like the Focusspot) can increase the danger though, by focusing or concentrating the beam.

[Tin Can]

I see there is talk of banning green lasers in USA, because of idiots pointing them at airplanes.

However, after I heard that, I noticed Amazon sells many very high power green lasers, but will not ship them to USA.

I don't know if that's a new policy.

[Drew Wiley]

Yes, some knothead nearly downed a commercial airliner down around Fresno by hitting the pilot with a green laser. His "prank" carries a terrorism charge with
a ten year minimum sentence, I think. Even toy red lasers can temporarily mess up your vision if you're hit in the eye. My eyes will go into spasms for about
twenty minutes. So there plenty of available ammunition even in "toy" stores out there for wannabee terrorists, esp in the drone and laser categories. The green
lasers I sell have OSHA-mandatory less-than-pinpoint line or dot characteristics. Amazon is the last outfit on earth I'd trust. Aren't they the folks that wanted to
develop thousands and thousands of drones delivering packages right to your door? Jet contrails are bad enough.