Cheap Canon DSLR optical trigger

Seagull DSLR Lightning Trigger

Seagull DSLR Lightning Trigger

This basic hack is very useful for certain situations where an infrared remote cannot be pointed directly at the camera, the distance is too far, or a corded shutter release is not practical. The list goes on. Basic searching has led me to lightning triggers which behave exactly as this, though they are generally purpose built for lightning with more features. The problem with lightning triggers is that they are expensive to buy or time consuming(ish) to make. This on the other hand is very cheap and simple to make.

Hopefully this will also work as a lightning trigger. Rest assured I will be in the next lightning storm I can find to test this and report back. It works great in my indoor testing (by bouncing a low powered flash off walls), so I think it should work with bright lightning (actual strikes).

UPDATE: This may not work well in distant lightning storms (I tried in a small one with no direct or big flashes in front of the camera). I have seen reports that this works better if you remove the front lens from the Seagull Trigger and something clear to cover it. Let me know in the comments if you have tried this and had success.


Shutter lag.

All cameras have shutter lag. Shutter lag is the time it takes from pressing the shutter button, to the time the actual shutter goes off. In modern DSLR’s, the lag is minimal and usually under 100ms. Though this means the Seagull trigger will not activate the shutter in time to capture the first flash burst. In the case of lightning this is not necessarily a major problem because there are quite often multiple flashes following each other. The same is achieved with a flash burst. It activates the shutter but not fast enough for it to capture the flash’s light. This is both a good and a bad thing depending on how you want to use it. I have a passion for night shooting and long exposures so I think it will work quite well for me. Hopefully it will work with lightning.

In the case of lightning (currently untested), using manual mode with a reasonably long shutter speed should work fine. It should trigger the shutter on the first flash of lightning and any flashes thereafter will be captured by the long exposure. This would help take out the hit and miss of taking lots of exposures in the hope you randomly capture a flash.

Things you’ll need:

  • Seagull Infrared Flash Remote Trigger for Digital Camera SYK-3 (around AUD $6)
  • Stereo 2.5mm Audio Jack (i used a 2.5-3.5mm Converter with a 3.5mm jack and cable – $2)
    • Refer to this page for the remote jack wiring diagram and explanation. I used a stereo jack so I can later add a switch enable or disable the focus circuit. Using a mono jack means the focus is always activated.
  • Basic soldering skills
  • Canon DSLR with 2.5mm Remote jack. This will most likely work on other DSLR’s but I haven’t looked into the way they trigger their shutters via remote.

Step 1: Open the Flash Slave

The back panel of the flash slave pops off easily if you pry around the edges with a small flat-head screwdriver. Once its open you’ll notice some foam that keeps the PCB inside from moving around. Pull out the foam to reveal the PCB.  Unscrewing the hot shoe from the top makes pulling the PCB out much easier as it allows you some extra cable movement inside.

Seagull unit opened

Seagull unit opened with PCB exposed

Step 2: Solder to the PCB

Note that there two small wires (pictured above) connecting to the hot shoe from the PCB. One is for the ground of the circuit (green), and the other for signal (red).

I soldered mine directly to the PCB and removed the connections to the hot shoe. You could choose to leave the wires soldered to the hot shoe in the event you wanted to use it as a flash slave as well.

I also soldered the focus wire to my earth to enable constant focus/metering. I will eventually add a switch to easily enable/disable this. Enabled it means that the response of the camera is much faster as it is already focused for a shot. If you just use the trigger circuit then the camera has to focus then activate the shutter resulting in a longer delay.

Remote cable soldered to PCB

Remote cable soldered to PCB

Front View

Front View

Step 3: Test

Plug your your new optical trigger into your camera and give it a whirl! With the jack plugged in the camera will be in focus mode (as if the shutter button is half depressed). Use a flash and pop it towards your new trigger. It should activate your camera shutter if all goes well.

Side by side

Side by side

Rear View

Rear View

It works perfectly for me so here’s hoping it works as well for you.

Feel free to leave your feedback!




You could also try the Magic Lantern Firmware for Canon DSLR’s which has an inbuilt exposure trigger.

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