Jump to content
ProfF

Laser guided snoot - in-line targeting

Recommended Posts

Hi,

 

As a photographer and 3D printing enthusiast I created several snots. Usually I find them hard to work with and did not use them much. I recently read article/review about 10bar laser guided snoot. I liked the idea and purchased the laser unit alone for 75$.

 

The laser unit is nice. It is basically a small box with a laser and a flash detector for autoshut-off. I started playing with the design of my snoot and looked at the 10bar original.

 

10bar-snoot-z240.jpg

Their design has the laser unit "riding" on the snoot, and the user has an adjustable knob to adjust the angle of the laser. This means that the beam intersect the actual snoot output path only on one point. Elsewhere it will be off center (and probably off target in the thin version of the snoot).

 

post-25106-0-43417900-1463368471_thumb.png

 

An ideal solution for this would have the laser run through the center of the snoot, this will make it precise at any distance. I knew similar solution from microscopes using beam splitter. The idea is simple. A beam splitter is half-mirror, where 50% of the light pass through it and 50% bounce off. In this design the laser is positioned perpendicular to the strobe. The beam splitter is setup at 45degrees to both beams.

 

post-25106-0-97767100-1463368535_thumb.png

 

The price of this solution is reduction in 1/2 of both the laser beam and the strobe light. Since this setup is used for close macro situation, I reasoned that this will not be a big problem.

 

The next question was finding a beam splitter. A professional grade one is expensive (100s of $). However, I found that there is a game "Khet - Eye of Horus" that uses lasers and beam splitter.

 

31eKehAZnqL.jpg

 

For about ~$5 I could buy two beam splitters pieces. A quick test showed that these work fine on the laser beam and on the strobe. Removing the plastic frame, I had a nice beam splitter (and a backup one).

 

I designed a snoot and set out to test it. However, the laser beam was lost somewhere in the snoot. Revisiting my components I discovered that the laser beam was not aligned with its housing. The few degrees of offset were sufficient to cause problems. This required having an adjustable mount for the laser that allowed tuning of the beam.

 

The final design in my CAD visualization:

 

post-25106-0-91383000-1463369708_thumb.png

 

The yellow object is YS-01 strobe. The blue ring is attached to the strobe and allows quick attachment of the snoot. The red box is the laser. The tip at the end is exchangeable and is held in place by magnets. (I did not take a proper picture of the snoot, but can load one later on)

 

Last month I had a chance to try it on a short visit to the red sea. Using the snoot with a macro lens was harder than I expected. The problem was getting the damn red point into the frame. I practiced on a pair of nudis, and finally managed few shots.

post-25106-0-45059100-1463370190_thumb.jpg

 

Opening the images on my computer, I realized that the laser was visible in the image, the auto-shutoff did not work. I set the sensor on the laser to point into the strobe, and expected the bounced light to reach it. It seems that the black plastic was doing a good job of absorbing the light. Taping a piece of white plastic on the inner lower wall of the strobe solved that problem.

 

The next day I tried the snoot with a fisheye setup. This made it easier to find where the laser is pointing and positioning it. Two attempts:

post-25106-0-26812100-1463370460_thumb.jpg

 

post-25106-0-43214700-1463370475_thumb.jpg

 

Not perfect, but something to work with. Since my trip was short, I did not have too much time to get more experience with the snoot. Next time hopefully I will get a better sense of it.

Edited by ProfF
  • Like 3

Share this post


Link to post
Share on other sites

Sponsors

Advertisements



×
×
  • Create New...