One of the biggest problems we face as photographers is keeping that DSLR sensor clean when shooting, especially when shooting outdoors. Your sensor is the primary component inside your camera for capturing and preserving those moments to the memory card and needs to always be in the best possible condition and clean to take great photos. Dirt, dust, oils and general grime on the sensor will show up on your images and make them look badly such as the example below from The Digital picture.com
Those two spots you see are from sensor dust and they are imbedded in your image. Now you can remove them using Photoshop, Lightroom and some other editing programs, but why not prevent them all together? I am going to give you some tips for keeping the dust and dirt out of your sensor.
1.) Never touch the inside of your DSLR, especially with you fingers. The internal workings behind your lens are not meant for your fingers so, keep them out!
2.) Only change your lens in a semi controlled environment. What I mean by this is don’t change your lenses outdoors in 35mph winds as you are just asking for sensor dirt.
3.) Keep your camera pointed down when changing lenses. I am not sure why so many people don’t get this one. Holding the camera with the opening facing forward or up just invites the dirt in, holding it down makes it harder for it to get in.
4.) Never change the lens with the camera powered on. Will it ruin your camera to do so, no but it will keep a static charge inside the shutter area and allow dust to be drawn to your sensor like a magnet.
I have found, one of the easiest ways to keep my sensor clean is just limit how often I change lenses. I never change them outdoors if I can help it. I carry 2-3 bodies when I am shooting outdoors and I equip one body with a wide angle lens for landscapes, the second one will have a portrait lens of some sort for capturing people and my third will have a nice telephoto zoom for anything else I might need to shoot. Now I know you are thinking “I’m not rich enough to afford 2-3 camera bodies.” You’d be surprised the deals you can find at local pawn shops or yard sales, often people don’t realize what they have and will sell the bodies cheap. Also, who says you need the latest, most expensive body out there. Instead of buying one $1,000-$3,000 body, use that money to buy 2-3 bodies that are cheaper because they are the older model, like getting a Canon 1Ds full frame for $500 that was made in 2004 but still shoots great, instead of the Canon 1Dx which runs $7,000. Too many people don’t seem to realize that it is not the camera that takes the great images, it’s the person behind it.