One of the great achievements of the first truly digital camera system, Four Thirds, was the invention back in 2003 of the supersonic wave filter, the first dust reduction system ever that cleaned the sensor at each camera startup. Right, it came with the honorable Olympus E-1. Today that’s standard equipment — not entirely foolproof, but certainly better than nothing. The only other best thing is to never change lenses. Or to be a dedicated single-lens shooter, even though you explicitly bought a DSLR — or mirrorless for that — to use the optics you need in each particular situation. Dust in a camera is just one of those things in life no one and no technique can avoid. Over time, dust creeps in anywhere, even if you use the built-in cleaning system. So… how to minimize dust?
The easiest way to find out whether a sensor is dust-specked or not is to set your camera to its narrowest aperture (F22 or thereabouts) and take a picture of a clear blue sky, white wall or an all-white computer screen. Then upload the photo and view it at actual pixel size. But honestly, I’d never too that because, as said, dust is a reality of life. If dust doesn’t show up in “normal” images, why bother. no big deal. You can peacefully ignore it, and nobody will mind one bit. If though you have those ugly specks, either clean the sensor or get it cleaned. Or some camera makers offer an “image dust off” option, a tool which, when activated, can remove dust from files. Right, a kind of dust-deleting software. Some cameras have a feature that identifies dust that’s stuck to the filter and automatically maps it out of the picture when capturing an image. Or remove dust in post-processing.
The best solution? Prevention.
The best way to deal with dust is not to let it in the camera in the first place.
When changing lenses, avoid to do so in the open or in a busy environment with lots of people. Find a protected, non-windy, non-dusty place. Turn the camera off to avoid dust collection on the sensor from static charge and point the camera towards the ground so gravity works with you to keep dust out.
Never place your camera on the bare ground without a lens or cap on. Protect it if necessary with a jacket, a bag or your back to the wind to avoid dust blowing into the open camera. Change the lens in a vehicle? The interior of cars can actually be quite dusty, it’s still better though than open space near a busy road.
Or you’re on a roll during a shoot, suddenly need a wider or longer lens and find no safe place to change that darn lens? I’d not change lenses at all in dusty places. Then better go with an all-purpose zoom and use it for the whole shoot if you know from the beginning that you gonna work in a windy desert, at a wild party or in an abandoned building.
Change lenses only if you have to, and before mounting the new lens make sure the optics are free of dust. Means to also blow dust off the body cap before placing it on the camera. And make sure the outside of the camera and lens is clean before changing lenses again.
Right, keep your camera bag dust-free, too, and vacuum it out periodically. Shake it upside down and avoid putting your camera in a bag with lint and bits of crud. And more importantly: avoid cleaning sensors like the plague. You can shoot 100,000 images without touching the sensor to clean it once.
But again, rule number one: try to avoid changing lenses in field in the first place. The best way to clean gear is not to get it dirty. No matter how careful you are, the sensor will get dirty. Isn’t that a great argument to get a second, if not a third backup body for those other lenses you absolutely need.