The idea of using Arduino for measuring camera shutter timings is not new. What I've tried to do here, is to make a modular system with a set of features normally offered in professional testers, at the same time to keep its design simple and available to reproduce using off-the-shelf components.

Usually, time counting and/or light accumulating methods are used to test cameras. For the time counting method, you need a light sensor, a time counter, and a simple light source. With such setup you can measure exposure time(s) provided by a shutter, curtains travel speed of a focal plane shutter, flash sync contact delays, etc. For the second method, you'll need a photosensor able to measure the amount of light and a calibrated light source. With such setup, you'll be able to measure actual exposure produced by a system "camera+lens", light meter accuracy, operation of auto-exposure cameras, etc.

This camera tester kit allows you to perform various both time-based and light accumulating tests, and calibrations of film cameras. What makes this Kit special is that it offers a tested solution with a great user interface and the ability to extend its functionality.

On a photo you can see an example of a finished product together with a calibrated light source. I constantly continue to work on new features as additional sensors and enclosure options.

Features

• Measures actual exposure at the film plane, which allows to test fully automatic, aperture or shutter priority cameras. Calibrated Light Source and Sensor #6 are required for this mode.
• Measures exposure time at the center of a frame of simple (leaf) and focal plane shutters of 35mm and Medium Format (6x6 or 6x45 using adapter) cameras.
• Measures timings of focal plane shutters with curtains traveling vertically or horizontally. Results can be represented in a few different ways to help you detect different flaws in a shutter operation, such as curtains capping or tapering, uneven travel speed, etc. Automatically re-calculates curtains travel time according to selected frame width or height.
• Measures delays between flash contact and shutter opening. Automatically identifies X, M, or FP modes.
• Takes a series of measurements, and calculates average stats. The number of tests in series can be selected in the Settings menu between 3, 5, 10, or 20.
• Automatically detects the type of connected Sensors, and notifies you if the wrong sensor is connected for a specific Mode.
• Automatically detects target speed used to calculate the error. Target speed can be set to "Auto" or pre-set from a list of standard speeds.
• Allows to check accuracy and calibrate light meters and light meters built into a cameras.

Characteristics

• Range of measured speeds from 8s to 1/8000
• target speed can be presented using old, new or logarithmic sets of speeds.
• Accuracy of time-based measurements
• ±10µs (measured in the pre-set environment, using a signal generator and specialized light source).
• Accuracy of light integrating measurements
• ±0.05EV within 6-14EV range, although full range 4-16EV of a Light Unit can be used during the tests.
• Resolution 0.01EV
• Light Source
• brightness is adjustable within 4-16EV range
• brightness levels can be switched between K12.5 and K14.03.

Kit components

• Arduino Nano compatible board with latest Firmware. uploaded
• Shield PCB, with two Sockets for connecting sensors
• LCD display 20x4
• Keypad (with vertical or horizontal controls orientation, depends on your choice of enclosure for the project)
• Sensor #1 - sensor with three diagonally placed photodiodes, for testing focal plane shutters. Its frame edge is designed to snuggly fit in a frame opening of most cameras without touching the curtains.
• Sensor #2 - sensor with single photodiode at the center, for older cameras with simple shutters. Its frame edge is made smaller to fit older cameras, since those may have either smaller frame openings, sprockets, or some pins protruding, which will not allow you to fit a bigger sensor. Also, this sensor comes with an adapter for easy placement in the frame opening of a medium format 6x6 or 6x45 cameras.

Full parts list of each component you can find at BOM page, as well as Assembly Instructions.

Optional components

• Light Unit #2 Rev.3 - Calibrated light source which allows to check accuracy and calibrate photometric light meters and light meters built into a cameras.
• Sensor #6 - in combination with Calibrated Light Source allows to measure actual exposure at the film plane.
• Sensor #7 - sensor with standard PC connector used to test flash sync or delay timings of a camera with simple or focal plane shutters. Please note, those sensors are optional. I made just a few, out of old used flash cables.

As mentioned above, for time-based measurements, you don't need a specialized light source, either a precise alignment, etc. The best choice of the light source would be a standard desk lamp with an incandescent light bulb or a bright LED panel placed in front of a camera in the proximity of 5-15cm. Recommended brightness is about 15EV, however, the Tester will work within a range of 13-16EV and readings may vary slightly. But, keep in mind, that photodiodes used for the Sensors are most sensitive to red to infrared light. Thus some bright white cheap LEDs (with color temp 6500K and poor CRI) won't work, because their spectrum lies mostly in the blue range.

More about Light Source for the Camera Tester you can read here

Power supply

You have a few options how to power the device:

• From a 7..12V regulated or unregulated power source. Power will be regulated down to 5V by a voltage regulator of the Arduino board.
• From a 5V regulated power source. Connector for a power supply wires in such case should be soldered to pins labeled as "5V"
• Via USB cable connected directly to Arduino board.
• Also, there is a reserved space and connections for a small voltage regulator, in case you chose to power the device with 24V or else.

Warning

Always double-check the polarity of the connected power source before powering the device. The device is not equipped with any protection against reversed polarity.