Arduino Camera Shutter Tester - the Shutter Tester

Fully featured & 100% accurate Arduino based film camera Shutter Tester

The Shutter Tester

There are many different shutter Tester circuits on the web. However, most of them simply do not work accurately. Rest assured, this one works 100% accurately.

At slower speeds, other testers maybe ok, but as 'speed' increases, the accuracy will rapidly decline, giving spectacular under-'speed' readings.

This is because of a fundamental mis-understanding how focal-plane shutters actually work and how to measure them.

The shutter 'speed' does not in fact change. There are two curtains in a focal-plane shutter mechanism and it is the time between the first curtain being released and the second being released, which controls exposure.

So we actually have to measure the slot-width between the two curtains, i.e. the gap that allows light to hit the film.

The error is exaggerated because the sensors have width, far greater than a single photon. Unless calibration is applied to correct sensor width vs photon width, great reading errors will occur.

Similarly, if the two curtains are not balanced correctly, they will cause exposure variation across the frame, often resulting in one side being far brighter or over-exposed than the other. A shutter tester has to measure and display this, whilst others cannot (single senor, sound recorded Audacity or 'plug' type tester) The Shutter Tester does all of this and more.

There are two versions of the the The Shutter Tester, this Instructable is for the Arduino version

The Shutter Tester Arduino

Arduino remains a very popular platform. Many people are familiar with Arduino and have many of the parts to make The Shutter Tester. The Shutter Tester will accurately display the shutter 'speed' and crucially the travel time of each curtain.

Shutter problems, like bounce and capping can easily be identified. Average shutter & curtain travel times are recorded and displayed.

The Arduino platform, makes The Shutter Tester cheap and easy to make, using easily available and cheap modules. No complicated circuit boards or 3d printed parts are required.

Cost to make The shutter Tester with parts from Aliexpress is £16 (+ local tax) at time of writing.

Optional parts, project box etc not included in the above price.

The Shutter Tester ESP32 (See separate Instructable)

The second version, is still Arduino based, but uses a much faster ESP32 processor and TFT display. This version can be found on my Instructables & Github. It is a slightly more complex build, as it has additional buttons, a rotary encoder and TFT screen, requiring more wiring, a project box and some soldering.

Whilst documents here are kept up to date, the latest versions always go to Github first.

Instructables do not allow hosting of the firmware, so for this, drivers and flash tools, are found on Github.

There is a full forum thread, with discussion & help.

(1) Build a shutter tester for Focal Plane shutters - Cheap, Easy & it Works | Page 23 | Photrio.com Photography Forums

Latest documents & Firmware

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Parts required are cheap and easy to obtain. The attached document lists them all, as well as optional items.

At the heart is an Arduino Nano board, costing less than £2. An Arduino Uno board would work as well, but not fit into the screw-terminal board.

Two push-buttons are required (a four-button module is shown in the photo)

The sensors are pre-made modules and the light sources are a matching pair of very low power Lasers. Again all readily available at cheap prices.

The test results are shown on a four line LCD module and optionally can be displayed on the computer screen, which gives more detail than the LCD alone.

The Arduino is easily connected to the modules, either using Dupont wires, which Arduino users will be familiar with, or pre-made JST XH connectors, which cost little more than Dupont wires.

There is no soldering required, although it can make things a little neater when connecting the sensors, as there are lots of 5V and 0V wires.

The comprehensive build guide and schematic diagram is attached.

The LCD shows the latest test data and accumulated average. More detailed results can be displayed on the computer screen, using a program called Arduino IDE.

Those familiar with Arduino will already have this program. Attached is a guide how to install it and another detailing driver installation if your computer does not auto-install it.

The software and drivers themselves are found on Github.

The Shutter Tester firmware is supplied as pre-complied (.hex) file.

This file has to transferred, or 'flashed' onto the Arduino board. This is easily accomplished using a small piece of software called AVRDUDESS

Detailed instructions are attached.

The firmware and AVRDUDESS can be found on Github.

Here is the User Guide.

It explains all of the functions & how to use them.

On first uses, a one-time passkey is required.

This is supplied free of charge upon request. The quickest way is a DM to the originator on Photrio.

The photo shows the sensor frame, simply made from scrap wood, with the sensors & Lasers hot-glued in place.

This works very well. Other users have used project boxes or even 3d printed parts to make a neat sensor frame.

The central card is a test piece, to simulate the slot in a focal-plane shutter.

The parts list details a suitable box for The Shutter Timer.

A 'build a box' document will be added shortly.

However The shutter Timer does not have to be boxed, it can be left loose, as some of the photographs of other users builds, show.