hacks · ideas · thoughts

Ok, so I got a used DSLR. What I didn’t pay attention to was the fact that the shutter has a certain life cycle. According to sources on –wait for it– Google, the EOS 20D has a life expectancy of 100,000 shots. Small number I thought. So I searched and searched, and after a while with good keywords comes this guide.

For the EOS Canon users. You can see how many times the shutter actuated using a hex editor and a RAW file. Tools needed:

• Hex Editor (XVI32 Preferred You can download it here FOR FREE!)
• RAW Image file from your camera

Baiscly what your doing is getting the number located at 95D and 95E and converting it from HEX to DECIMAL. If you do not know exactly how to do this. I will show you below

Step By Step Documentation using Xvi32.

1. Load Xvi32
2. Go to Tools>Options>Data Inspector (it’s a TAB)
3. Click “big-endian (MOTOROLA)”
4. Click “OK” Button to exit out of the options
5. Go to File>Open>”CHOOSE YOUR RAW IMAGE FILE” then click open
6. Go to Address>Goto (Or CTRL+G)
7. Click “Hexadecimal” then TYPE “95D” into the box below
8. Click “OK”
9. Then go to TOOLS>DECODE NUMBER
10. LOOK at “XX XX As Word” (XX Being your numbers located in 95D,E).
11. The number next to it is your Actuation number.

Good deal, so I took a picture, copied the raw file over gphoto2, fired up xxd and do some processing. And I got 10414 as my shutter count. Subtracting around one thousand shots I’ve taken since I bought the camera, I thought I got a pretty good deal ;)

Some say life’s too short to worry about shutter break-down. But it’s nice to know where you’re at anyways. So, if you have a 20d and run Linux, try this at home

echo $((0x`xxd YOUR_RAW_FILE_HERE.CR2|head -150|grep "0000950:"|cut --characters=42,43,45,46`))

PS: There are some guides said you can just read the EXIF tag off the JPEG file from some reader and/or flickr but from personal experiences I do not find this to be correct. I tried with two consecutive files and the shutter counts differ greatly. So be warned :)