Projects: Camera Modifications

One of the most common camera accessories at the South Pole is the remote trigger. Remote triggers provide an alternative to using the shutter button mounted on the camera which gives the operator a few advantages:

• For long exposures (longer than one-tenth of a second, but shorter than two seconds) or very long telephoto lenses, moving the trigger off the camera prevents any camera movement from pushing the button.
• Many remote triggers have can be locked in the “on” position, meaning the camera will continually take pictures as long as the trigger remains plugged in.
• The buttons are often larger, making them easier to use with gloves (or many layers of gloves and mittens, as the case may be).

For me, the first point is not very important. Over a 20-30 second exposure, some small movements in the first second are unimportant. However, the ease of use and the lock are very useful. Unfortunately, the standard insulation used on the vast majority of cables will freeze and crack at standard South Pole temperatures, so I replaced it with a cold-resistant cable.

The wire I used is a coaxial cable with two conductors. In the picture above, you can see one in the center, and one spread around the outside (this configuration is very useful when you need to transmit high-speed signals over long distances, but it is overkill for my use). The outside is a silicone insulator. The insulator between the conductors is silicone as well, but much softer, so the cable remains flexible. Silicone maintains its flexibility to temperatures well below anything we see at the South Pole (or any natural environment in the world). I got a small section of this cable from Robert Schwarz, the Keck Array winterover.

My initial intention was to just replace most of the original black cable with a short section of silicone cable. However, I decided that was too boring, and that I was going to be ambitious. I replaced the entire cable. That meant I had to open up the trigger itself to detach the original cable from the contacts, and solder mine in place. That was relatively easy. The hard part was removing the original cable from the plug and replacing it with my own.

Nikon uses a very complicated plug for its remote triggers (in fact, it uses about seven different plugs, depending on which camera you have). This plug is not only capable of triggering the shutter, but it can also communicate with GPS devices and other complicated electronics. So, instead of a simple three-contact plug, I had to work with something the size of a mini-usb plug that had eight contacts. In order to even access the contacts, I had to dig through several layers of plastic. After that, it was easy to solder on the new cable.

However, I was then left with a plug that had almost unprotected wires. It would have broken in the course of one walk to or from DSL. I needed some sort of strain relief. Again, I got ambitious. I could have done something as simple as wrap the base of the plug in electrical tape, but I made an epoxy covering instead. Before it hardens, epoxy is quite runny, so I had to make a mold for it (see the picture to the right).
Unfortunately, the mold was a bit leaky, so I ended up with only a partial covering (the picture to the right shows the plug after sanding the epoxy). So, I had a make a second mold that didn’t leak.
The second mold was much easier to make, as I had already laid down the base. I simply used some aluminum tape.

The final step was to sand down the epoxy to create a more finished look.

The finished product (bottom) and the original (top).