I often use very small apertures—f/32, f/45, or even smaller—when I shoot with my 4×5 camera. With ASA 100 film, this easily leads to long exposures using a bulb shutter: four seconds, eight seconds, or sometimes as long as 120 seconds. I keep a stopwatch in my camera bag, holding it in my left hand while my right hand grips the shutter release. Technically, that works. Or I sometimes used the locking screw to hold the button down. The timing does not have to be exact.
However, I often miscount the time even though the stopwatch clearly shows it, and the film ends up either badly overexposed or severely underexposed. Over the years, I have wasted many sheets of film this way. In addition, during the exposure I have to hold both the stopwatch and the shutter release, which means I cannot move at all. This feels like a limitation of good old technology. I don’t mind being seen as a fool standing still with a stopwatch in one hand and a wired cable release attached to a strange wooden object on a tripod—but it is inconvenient.
One day, after I bought a 3D printer, I got a great idea: to build a shutter-release timer for a traditional cable release. Using an ESP32 microcontroller and a small stepper motor, I realized it should be possible to mechanically push and release the shutter button automatically. I began researching components and exploring 3D-printed designs for a linear actuator and gear mechanism. There are many examples online, and I discovered that my 3D design software includes tools for designing various types of gears.
The dimensions of a stepper motor that I ordered and received, can be found online easily. I designed a custom gearbox that could securely hold the motor. After several rounds of trial and error, I successfully printed a working gearbox. It has enough power to reliably push and release the shutter.
Once I confirmed that the gear box works, I started programing a timer for ESP32 to manipulate the stepper motor which is SG92R servo. This motor seems to be pretty common so there are many examples for ESP32 online. I referred some of them to finish a timer program and control the motor properly for my linear actuator gear. It was just matter of moving angle so it won’t hit the limit of the gear and the moving amount should be sufficient for the push button of the shutter release cable.
While designing an enclosure, I carefully considered how to securely position a shutter release button. My intention was to avoid permanently attaching it to the timer box, preferring the flexibility to connect or disconnect the release cable as needed. Although using an additional cable could make manual release possible, frequent attachment or detachment on the camera’s shutter side might be inconvenient and cause disturbing the lens or camera body. Moreover, I observed that fastening the cable end screw becomes challenging when the enclosure is affixed to the opposite end of the cable. I also aimed to avoid cutting or modifying the cable. Consequently, multiple iterations with trials and errors were necessary to ensure a secure fit for the button-side cable within the enclosure.
So far, this simple stopper can securely hold the shutter release cable.
For this project, I chose the ESP32-S3 Mini for this project because it’s compact yet offers enough GPIOs to connect an LCD, push buttons, and a stepper motor. The shutter speed adjusts in powers of 2 (e.g., 1sec, 2sec, 4sec, 8sec, 16sec, etc.), resembling real camera settings and making it easier to reach the desired exposure from the EV value.
There is a still room to be optimized by locating those components and the size of the box can be smaller.
One big thing I have not solved yet is a battery. ESP32 requires 5V as a power source. I’ve been using USB charger power adapter while developing this, but this shutter timer supposed to be used outside. I have researched lithium-ion battery, which is rechargeable, but it requires some more efforts. In fact, I want to consider integrating lithium-ion battery inside this enclosure, but for now I added USB-C port on the side of the box, and I can use a USB power pack temporally.
Test shot went well. The hydrangea in my garden was withering in a good way, and I picked one good shape blossom. I set it up in front of my camera connected the shutter timer box. It worked! It could release a shutter and made a 64 sec exposure.
The shooting went well and no issue was found in the process. One problem I just noticed is the place for the enclosure stay. I was thinking about some hook to hung it. But finally I printed an enclosure holder that can attached on the tripod legs instantly. It looks convenience and my hands will be free while exposing a film. But it may shake the tripod whenever I operate it. Let’s see how it works. As long as I get a good negative, I’m totally fine. Anyway, the first testing was done inside, and I can put the timer enclosure on a top of a plastic case. There is no concern about shaking the tripod. I could be totally relaxed and concentrate on the focus and composition. Then I just develop the sheets of film as I do usually. Here is the result.
Ilford Delta 100 F32 64sec
This is a scanned output from Epson V800. It is a bit overexposed which is my preferred exposing for film. I can see the texture of the shadow side of the flower and assume the highlight area can be burned to get texture more in a darkroom.
Conclusion, it works and useful. I’m going to keep it in my camera bag and like to use it with especially ND filter. But I now noticed one thing. I’ve been enjoying entire process of shooting with the large format camera. I love the feeling when I release a shutter. Small click come back to my fingers as soon as I press it, and the mechanical sound of shutters just arrives over my ears. The copal shutter attached lens is simple and the sound is crisp and quiet. It comes from only a leaf shutter and it does not involve any other noise such as mirror up, curtain travel and so on. Ah I might miss that moment of bliss…
Appendix
ESP32-S3
https://www.amazon.com/dp/B0CR2RH7PS
Stepping motor
https://www.amazon.com/dp/B0DXQ74VV6
Monitor
https://www.amazon.com/dp/B0BFD4X6YV
Auto Shutter Timer Arduino source code