Friday, June 12, 2009

Friday's Photo Tip - Keeping the Sensor Clean

Friday's Photo Tip - Keeping the Sensor Clean

a magnifying glass with a spotted handle

Spotting a dirty sensor can be pretty tricky at times - especially when you only view your photos on the computer at regular size.

Sometimes it takes printing them out, or viewing them at 100% in your photo processing program to see the signs of a dirty sensor.

Now, if you have a point and shoot camera, then you are all set and will not have to worry about this problem - your sensor is sealed inside your camera body safe and sound from any dust or dirt.

This post concerns those who shoot with DSLR cameras and interchange their lenses frequently.

Anna, over at My Only Photo, mentioned it in a comment last week, and it is something that is worth mentioning.

Each time we remove the lens from the camera body, it "breaks" the seal that protects the sensor that is hiding right behind the mirror inside the camera body.

When you take a picture, that mirror that you see when the lens is removed, flips up and exposes the sensor - which in the case of a DSLR, is the film.

So, any dust or dirt that gets on the mirror can easily get on the sensor. When this happens, it acts just like dust or dirt on a lens, and it shows as a black or brown spot in the photo.

Dust is even trickier because the sensor can "see" through it - but it leaves a blurry, uneven blob on the photo.

And remember, some of these are not even visible unless you view the photo as a print or enlarged in your processing program.

So, how does one avoid getting the dust and dirt on the sensor?

One tip that I read long before I owned my DSLR is something that I think makes the most sense:

When changing the lens, keep the camera body aimed down rather than up.

Let gravity work for you - dirt doesn't fall up, and if there is any on the mirror, chances are it will fall out too.

Be quick about it - have everything ready to make the change quickly.

Avoid wind - be it from a fan inside or the wind outside - that will make the dirt "fall up" no matter how you hold your camera body.

Now, as careful as you are, dust or dirt will get on your sensor at some point - it is a fact - no matter how hard you avoid it. The sensors are electrical, and this attracts dust all by itself.

Most of the time, just following the instructions in your manual for blowing it off will work.

There are several other solutions available, but I would offer a strong word of caution about doing this yourself. It is best to let a professional handle it for you.

The sensor in your camera is your camera - with out it you cannot take photos.

If you damage it, you can get it replaced, but it will cost as much as a new camera.

Damaging it is really easy, this piece is most sensitive and fragile and it is not worth taking a chance with it. Dirt scratches it's surface quite easily.

I have had my camera almost three years, and the quick puff method from my bulb blower has solved my dust and dirt problem each time.

I remember the first time I discovered a dust spot, I was beside myself with anxiety.

The last thing I wanted to do was even look at that sensor, forget about cleaning it.

In the end it wasn't as bad as I had imagined, but I still get apprehensive each time I have to do it.


  1. Thanks for the tip on cleaning, I have to take mine in to get cleaned professionally before my China trip. Cool mag glass, I have 3 for looking at meteorites, but I never seen anything like yours, very cool.

  2. Thanks for the tip, Kathy. I'm happy that even though I do have a D-SLR, I have not yet felt the need to change my lens. When and if I do, I will hold it facing downward. But I'm not sure if it's worth the anxiety to even bother. My lens has a large focal range and I don't imagine needing a wider range, except maybe for macro shots.

    Lately I'm submitting to Shutterstock, and one thing I've learned is to look at my images at 100%, for noise and artifacts.

    Happy shooting! :)

  3. Oh Kathy I should have been here earlier, lol, thanks for the mention. You know I was really stupid first time with my DSLR, I actually changed the lens on the dusty day during trips to the mountains, dry and dusty, and I got these circles not knowing what it is. Once in the while I point and shoot the sun or bright sky, it reveals lot of dust this way. And then I call my technician [my husband] to clean, lol. Kathy, thanks again. Anna :)


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