Some things *I* learned about photography - Pt.24
44. There's dust in the wind and about everywhere else
While doing some internet-research on landscape photography for my trip to Greece, I stumbled upon various posts about sensor-dust and how to get rid of it.
Especially with landscape-photography, sensor dust seems to be a big issue, because you very often use small apertures ( = big f-stop numbers) and with those, the dust becomes visible. This is due to a "sharper beam of light" with smaller iris-openings. The visible dust is not the dust itself, but the shadow of the dust, that is lying on the coating of the sensor.
I never experienced problems with sensor dust yet, so I was really astounded to read, how big this issue obviously seems to be.
To be very honest, I'm not too careful, when it comes to changing lenses on my DSLR. I even changed lenses numerous times during my safari in quite dusty Tsavo East Nationalpark. And changing lenses is the main reason, why dust gets into the camera (another reason are zoom-lenses, that are not completely air-tight).
So I grabbed my camera and did some tests with f22 and higher
This is a picture shot at f32 of the clear blue sky. The dark spots you see are actually dust on the sensor.
To see it more clearly, I "enhanced" it by increasing the contrast
Why didn't I realize this enormous amount of dirt on my sensor?
The answer is easy:
Because I almost never shoot with the aperture that much closed. I played around a bit and at f10 and lower, the dust wasn't visible at all.
So, how to get rid of the dust? The built-in sensor cleaning of (newer) DSLRs do quite a good job, but nevertheless one of the (few) must-have accessories IMHO is a rocket-blower (or similar), to blow the dust off the sensor. There are also liquid sensor cleaners, but I haven't tried them yet.
Of course you can also give your camera to a service, where it gets professionally cleaned as well, which I think I might do in not too far future.
