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Laser Guided Macro Shooting

LG-H850

When shooting hand-held macro photography in the field, sometimes framing may become very hard. On top of the fact that your extremely shallow depth of field, sometimes you may find yourself in a very awkward position. One camera in one hand, flashlight on the other, standing on one leg and leaning over a bush… And just before taking an usable photo, you loose your balance and make the subject fly away. I am sure anyone shooting macro with a hand-held camera do know exactly what I mean.

Moreover, I have been in situations which is too dangerous or impossible to look through the LG-H850viewfinder

 

and I tried to shoot using the LCD screen. LCD screen (at least mine – Nikon D7100) has a terrible delay. Which makes things even more difficult in situations that you need quick reflexes. Mine is also fixed, so I cannot change its angle which makes it for most situations completely unusable. At some point I even tried shooting without looking at all. I actually shoot some usable images with guessing. But my success ratio is about 1/200-300.

First I was thinking to fix a high fps camera in front of the viewfinder. But quickly realized it wont work in low light conditions. Considered that macro needs lots of light, it is practically not applicable. A silly thought like a camera which also projects light crossed my mind and I realized that I can project light from the viewfinder to the object to lighten it up. Which lead me to another Idea: “I can use a laser pointer for targeting the right direction”. However, a quick google search showed me that I wasnt the first one to think that :))

Note to myself: next time make sure that you made a proper research about the goal you want to achieve.

In this topic you can find a detailed explanation of how one can be done.

remoteShutter

Yongnuo 603n Triggers sends these commands. I used this signal to trigger the relay which turns off the laser

There are always more things to do

If I have to summirize, the logic is very simple. Laser photons are coherent which means crests and throughs of the wave are in lockstep. And because it is coherent it stays focused for long distances. However, going through a lens makes it unfocused and it becomes focus only within the actual depth of field. This way, if a crossed line laser is used it is easy to understand to magnification ratio (the cross becomes larger), the focus area and direction.

There are two things with this design which makes it unsuitable for hand-held field shooting. First it is not compact enough. Although the adapter can be replaced with a battery pack, it has a long cable. This is a thing that can be dealt very easily. The real problem is,  when you shine light through the viewfinder, despite of the closed mirror during shooting, it finds its way to the sensor. That is why manufacturers always encourage users to use viewfinder caps while using the LCD instead of looking through the viewfinder.

If you are using a cross line Laser, It is also possible to estimate which area is in focus. The image on the right shows that the focus area is in the middle of the frame. The upper and lower parts are out of focus.

For this first prototype, I used a simple 5v relay module to get the signal from a cheap yongnuo 603n-II wireless trigger and shut down the laser when the button is pressed. I used a mechanical Relay module becausethese ones have also the NC output. NC in here stands for “Normally Closed”. So if you connect the device to NC and Com, the circuits is closed as long as there is no input signal. Meaning it is a simple way to invert the signal. Mechanical relay LGFresponses are not that fast and their life is limited. However, since this is the first conceptual approach, it is suitable for that. Besides, response time is not that much important if it gets closed with the focus signal, as well as shutter signal. If you short Ring input to the Tip input, it will work. Lastly, I added another switch which turns of the system for battery saving

For prototyping purposes, I used 3 Yongnuo 603n-II (actually 2X 603n-II and 1x 603) and 1x Yongnuo 560-IV Flashlight. One wireless trigger triggers the the flash and camera, other one triggers the laser and the last one triggers them all, which I also use as for the shutter button. This is of course very unnecessary, it could easily done with two triggers if you use the top camera trigger to trigger both camera and laser. Since I am pretty afraid of dealing with the camera trigger and I almost always fail at connect things at the first try, I did not wanted to jeopardize my camera. It is also possible use only one transmitter and use the dslrs shutter release button, but again, I skipped the idea for the initial prototype. I used a 3d printed frame to fix the laser to the viewfinder. You can download the stl file from here. Note that it is compatible with the laser modules with a diameter of 12mm. Lastly I used a 3.7 Lipo battery for toy drones. These chinese Laser pointers are very sensitive and they will most probably burn if you pass the limited voltage. 5v for this case.

3 Radio triggers. One trigger to trigger the laser, one trigger to trigger the camera, one trigger to trigger them all and in the darkness bind them.

3 Radio triggers. One trigger to trigger the laser, one trigger to trigger the camera, one trigger to trigger them all and in the darkness bind them.

The Big Bad Ugly Setup

First be sure that each trigger uses the same channels and all of them set to tx mode. Plug two triggers on top of the camera hot shoe as a stack. Connect shutter release cables from one to the camera and other one to the Laser Guide module. Plug the remaining trigger under the flash. I use this one as the shutter button. Actually it takes a little time to adjust but I use my little finger to push the button while holding the flash with my left hand. You can unplug this and use it as a remote if either your camera or flash fixed somewhere. (Or you can bite it if you want)

650nm-5mW-red-laser-module-OEM-red-laser-New-Arrival-650nm-5mW-36V-Diode-Module-135mm

I used a Cross Line Laser Module with 12mm Diameter

This test setup, as I said before, is too bulky, but I think it can be still usable, especially in low light or even night time macro conditions. To compensate the bright sunlight a more powerful laser can be used but it may easily become a weapon rather then a guiding device.

Next time i will make it more compact. I will make a proper circuit with either a solid state relay or an optocoupler. The system will be better looking and will take less space. On top of that I am actually planning to add something very interesting.

 

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