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Do your photos have spots like this?
Dust in photos is a fact of life with digital SLR cameras. The world is not a clean place,
and we often find that the most interesting photos happen in the most difficult environments. Luckily, this is a problem that can be solved easily and quickly.
First, let's take a test photo to find out if there is dust on the sensor. Here's how:
1) Set the exposure mode to A (or Av). Depending on your model, this is done by turning a mode dial on the top
of the camera, or by pressing and holding the MODE button while turning the control dial until "A" or "Av" appears
on the display.
2) Set the aperture to f/22 (or as close as you can get). Use the control dial to change the f/stop. The shutter
speed number will also be changing as you do this.
3) Set the camera to Manual Focus. Some cameras have a switch on the body, usually located near the lens mount. Other systems have a switch on the lens itself - typically labeled "A/M" - "M", or "S" - "C" - "M". Once in manual focus, adjust the focus to infinity (in manual focus mode, it should turn smoothly, without resistance - do NOT force the motor).
4) Point the camera at a light-colored surface with even illumination - avoid contrasts or bright or shadowed areas.
Most walls work nicely, as does a computer monitor with a blank white screen. As you take a photo of the surface, move the camera around (but keep it pointed toward the surface).
The goal here is to take a blurry photo of the surface - by keeping it out of focus, and also moving the camera during the exposure. This way, you know that any dust you see is not on the surface, but inside the camera.
If you see any dark spots, then you've got dust on the sensor. Don't despair! We can
clean it for you quickly and professionally.
In Fig. 1a, we see the light path through the camera when you're looking through the viewfinder. Note that dust on the sensor is not visible, because the sensor is located behind the mirror, and is not in
the light path at this time.
Fig. 1a
But what if there are no spots on the photo, but you see dust in the viewfinder?
If you see dust when looking through the viewfinder of the camera, remove the lens. Now look through the
Camera's viewfinder (no image, just blurs of color now). If the dust is still visible through the viewfinder,
even with no lens attached, then you are looking at something in the viewfinder system. The good news is, this dust will not appear on your photographs. The entire viewfinder system is bypassed when you take a photo - that's why the viewfinder goes black every time you take an image.
Fig. 1b
(Note that the mirror is up, flat against the focusing screen. This blacks out the viewfinder system, and allows
the light from the lens to proceed directly to the sensor, without interference from the viewfinder).
Dust in the viewfinder can sometimes be very easy to clean, and sometimes it requires substantial disassembly of the camera. Here are some rules of thumb:
-If the dust is slightly diffuse or out-of-focus (be sure your diopter is set correctly for your eye first),
then it is probably on the bottom of the focusing screen, where it generally can be removed with a puff of air
(we recommend a hand-blower, not compressed air, and not your mouth!).
-if the dust is very crisply focused, it is deeper inside. It may be on the top side of the focusing screen,
where it is reasonably accessible, or it could be much deeper inside (further up in Fig. 1b), requiring a tear-down of the prism assembly.
In cases where the dust is deep inside, each customer must weigh the cost of cleaning against the annoyance
of having the dust there.
Some real gems:
 Nikon D200 4/09
 Canon EOS Digital Rebel 6/09
 Canon EOS 20D 7/09
 Pentax K200D 12/09
 Nikon D200 6/10
Once we've done a sensor cleaning, it looks like this:
 Same Nikon D200 from 6/10
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