Cleaning a DSLR Sensor (D70)

Okay, so a bit of a techie tip today because I figured it could come in handy for any other SLR beginner who has found themselves stricken with the dreaded 'dirty sensor' on their lovely new camera. This particular tutorial (of sorts...this is my first time doing it so if I break something you will learn what NOT to do at least!) is based around my Nikon D70, however, the process is much alike on most other DSLRs, you might just have to look up how to do particular stages on your specific camera (i.e. Locking up the mirror).

The Symptoms

After returning from Thailand recently I was distressed to find many of my photographs had a strange crescent shaped mark in the same place on every photo. I cleaned all my lenses thoroughly and took some test photos to see if it changed anything. The result: no such luck.


Note the stupid smudge above my stupid head.

In other words I had a dirty sensor. For the completely uninitiated the sensor is perhaps the key part inside your body unit that allows a digital SLR to function in the same manner as a film SLR. For more details read THIS or any other breakdown of the parts of a Digital SLR. Anyway, I had heard about this problem before, and also heard that the best solution for this was to take it to a shop and have the sensor cleaned professionally. Sensors are the 'Achilles Heel' of your DSLR and are very delicate. Treat it rough (actually, treat it anything less than the wafer thin slice that it is) and it is likely to bend, break or get really dirty, rendering your camera totally useless unless attended to by a pro. However, it is fairly safe to give in a surface clean by yourself providing you have the right gear and take adequate care.

STOP TALKING JOE! Show us how to bloody DO IT!

Okay, okay already! Talking of equipment the only stuff I have at hand to clean my sensor is a standard blower brush. You can purchase these at any decent photographic store (for Hong Kong dwellers Stanley Street, near Lan Kwai Fong has plenty of good places) and they are fairly cheap. There are dozens of fancy alternatives which you can no doubt find by Goog-ling DSLR Sensor Cleaning Equipment or something similar. I don't have any of them but is everything from fancy statically charged brushes to alcohol covered swabs for deeper cleans.

As a process, it is a fairly simple operation:

1. Turn off your camera and remove the lens, and then throw that out the window, you won't need it anymore. You may be tempted to give the mirror a quick brush and blow with a standard blower at this point as the problem may be located there. In my case it definitely wasn't.

2. Turn on the camera and from the menu select 'Mirror Lock Up'. This will obviously vary from camera to camera but it is not normally buried to far down any menu trees. On the D70 for instance it is right next to The 'Format CF' option. Hit it, and when prompted, press the shutter release button. This will flick up the mirror and reveal the sensor.

3. Now just give the sensor a gentle blow with your blower. BE CAREFUL and DO NOT touch the sensor with the brush. Any stupid moves now and you can wreck your camera. You might need a bit of light, I would recommend a head torch but I personally used the old 'torch between the teeth' method, probably a bad idea. I have also heard of people using compressed air/Co2 for this too, and have also heard horror stories about liquid residue then showing up on the sensor. Etc.

4. Turn the camera off and the mirror will lock back into place, then, go fish that lens out of the bush downstairs and take some test shots and see if that crud is gone. I found taking some simple shots of the sky in varying apertures gave a pretty good indication. Alternatively, if you want to see every last speck import your test shots into Photoshop/GIMP/Whatever and play with the levels until all is revealed!

Simple, eh? Not even worth a blog entry you may say. Yeah? Well I was bored at work and it was about the most exciting thing that happened yesterday. Anyway, as a closing note, remember that prevention is far more effective than this cleaning method. You would do better for yourself by just taking care changing lenses and trying to let as little dust or debris get inside you camera body as humanly possible. I'm not going to launch into a lecture about basic care of your SLR as I am not a hypocrite and I am pretty sure all of this came about as a result of me haphazardly changing lenses whilst sitting the back of an elephant (all the photographs before are fine, and all of those after have the strange mark). In short, look after your camera, and it will look after you. An apple a day keeps the doctor away. A penny in hand is worth two in the bush.

Blah, blah, blargh.

Hope this was useful!