Cognisys StackShot Connector

Previously, I discussed the wonders of using stacking software to combine the most in-focus portions of a series of images. You can manually take a series of photos with different focuses as long as you use a tripod and are careful not to nudge the camera’s aim while turning the focus ring. Automated rail systems, like the StackShot, avoid errors and speed the process by slowly stepping the camera towards the subject, while triggering the shutter with a remote circuit.

Unfortunately, upon receiving my StackShot, I discovered that it was incompatible with my Panasonic Lumix GH4 camera’s remote shutter input. Cognisys sells an interface box for $100, which seems like overkill.

It turns out that part of the issue is that the StackShot backdrives power into the camera port, which is odd. Simply adding a diode to my existing camera remote control solves the problem. When triggering, the StackShot connected to the RCA mono phono jack (Switchcraft PJRAN1X1U01AUX) shorts the resistors just like the shutter pushbutton does in the circuit. There is a voltage drop across the diode, but it is inconsequential with a 1N5817 at such low current.

Panasonic Lumix GH StackShot trigger schematic

Panasonic Lumix GH StackShot trigger schematic

Initially, I bodged the circuit together with a bunch of alligator clips. After verifying that it worked and that I would continue using it, I laid out the circuit in PCB software. I chose to include manual pushbuttons along with the RCA input, so that I wouldn’t need to change connectors throughout a shoot.

Manual and automated shutter trigger PCB design

Manual and automated shutter trigger PCB design

The boards only cost me $2 each, when ordered from OSH Park. With parts, the total circuit costs less than $10.

OSH Park order is inexpensive

OSH Park order is inexpensive

To save space, the Molex connector is mounted underneath. I kept the pinouts the same as my original board, so that I could reuse the cable. You’ll notice that I had to squeeze oversize resistors in place, because I didn’t have those resistance values in the smaller size package.

Panasonic Lumix trigger circuit with StackShot

Panasonic Lumix trigger circuit with StackShot

Okay, now we have everything needed to take clearly focused macro images. But, do they look nice? Of course not. Turn the page.