So you are about to buy a used DSLR cam from eBay. The model isn’t top-notch, but still solid quality and was released 2 years ago. The pictures on the auction page of the cam look good, but was the camera really rarely used as stated in the auction text? Or are you making your bid for an over-used device that already suffers from abrasion “diseases” like wobbly buttons?
Estimating the “true age” of a camera
The date of purchase isn’t a very reliable indicator, as the usage intensity of cameras can vary greatly. A 2-year-old DSLR that is mainly used at holidays or family events is surely in a better condition than one that serves as bi-weekly-party snapshot device.
It would be nice to have something like a mileage indicator for DSLRs, that more or less counts every picture ever taken with a particular cam. Luckily, such a magic indicator already exists, although its information isn’t always easy to obtain: The Shutter Count measures the number of shutter releases during the lifetime of your camera. A shutter is a moveable device, that exposes the camera sensor to the light during the shooting of the picture. Roughly spoken, the number of shutter releases approximately corresponds to the number of pictures taken with your camera.
Accessing the Shutter Count with exiftool
Unfortunately, the Shutter Count isn’t very easy to access. Only a few DSLR models from Nikon, Canon, Pentax and Samsung (green model names) dump this information out with their EXIF metadata. If you intend to buy such a camera, you can ask the seller to mail you an unmodified photo directly taken from the camera.
Jeffrey Friedl's Exif Viewer reports the Shutter count
You can then either upload the photo to Jeffrey Friedl’s Exif viewer or install the famous ExifTool metadata extractor on your system (Win/Mac/Linux). Open a shell/console, navigate to the directory where you stored the photo and type
on Windows or
exiftool THE_UNMODIFIED_IMAGE.JPG | find "Shutter Count"
on Linux or Mac OS.
exiftool THE_UNMODIFIED_IMAGE.JPG | grep Shutter Count
If a line like
Shutter Count: 2391
appears at your command prompt, your attempt was successful. If nothing appears, your model likely doesn’t include the shutter count in its metadata. NOTE: Only a few EXIF viewers will extract the Shutter Count value, as it is stored in the so-called Makernotes (proprietary extensions of the EXIF standard). To get reliable results, please use the tools I mentioned above.
The Firmware way
Anyway, there is still hope: a few Models, such as the popular Olympus E-Series cameras, allow you to access the shutter count by sniffing the camera’s firmware. The downside: you need physical access to the camera and some patience (or a reliable AND skilled person that does this for you). This guide shows you how to display the shutter count value on the screen of your Olympus E-Series camera.
Interpreting the numbers
You had a hard time to retrieve the shutter count, but what does the value mean? Is the cam still a teenager or already almost in heaven? Oleg Kikin maintains a Shutter Count life expectancy database. Users report their shutter count numbers and whether the cam is still alive or already trash.
While these numbers can give you some orientation, don’t forget to consider that a lot of factors impact the live expectancy of a DSLR: outdoor usage, storage or maintainance intervals. You should also be aware of the fact that shutter counts are not immutable. EXIF-based shutter counts can be manipulated quite easily, but also the firmware values aren’t immune: firmware upgrades or repairs may alter the shutter count.