I’ve been using my cameras hard for the past week. It was time to check the sensors, and see how much dust and gunk had built up.
Here’s how I do it. I aim my camera at the sky. I set it at f/22, at as short of a focal length as I can, and not have distracting details in the frame. I throw it out of focus, so that the only thing sharp will be the dust on the sensor. I look at the resulting frame at a moderate enlargement on the LCD.
There were a couple of spots that justified a cleaning, so I used a hand blower. It’s the only sensor cleaning tool I use. I checked again, and the sensor was covered with spots! What happened? I cleaned it again, and it was still a mess. Was I blowing more dust into the camera?
I turned on the shower on in the bathroom, cold, for several minutes. This is a way to quickly generate a dust-free environment. I blew out my sensor in there, then did another test. This time I discovered my problem: I had thrown out the focus so that the sky was blurry, but I was getting a very sharp picture of the window of my hotel room, which was, of course, covered in grime. My sensor is actually quite clean.
It’s amazing what obscure problems can generate an anxious response in me.
Well, now I have two great tips from this post:
1. Step outside before shooting the sky
2. The shower trick is one I'll use for sure.
Posted by: Jack Nelson | April 23, 2007 at 03:31 PM