Page 359 - Friedman Archives

Cleaning Mode 359

at all; whereas at f/32 it’s quite clear and sharp (see Figure 9-5). If you
tend to shoot wide open all of the time it is very easy to blissfully be
unaware of any sensor dust buildup that may be accumulating, but check it
often because the longer it stays there, the more difficult it is to remove.
Here’s a simple procedure for checking
if your sensor has dust:

 Get a white piece of paper and any
medium-range lens (such as
50mm).
 Put the lens into manual focus
mode and set the focus to infinity.
Set exposure compensation to +1
so the card comes out a little more
white.
 Put the camera into Aperture
Priority exposure mode and set the
f/stop to the highest number you Figure 9-6: To clean the sensor, first
can (such as f/16 or f/22). (This raise the mirror by pressing down on
makes the lens opening small, this button. Then clean the sensor
resulting in the dust becoming using the tools discussed in the text.
more visible.) (Note that Cleaning Mode isn’t even
 Shoot one frame. necessary.) Let’s be careful in there!
Then examine your image closely on
the computer. It is recommended that this procedure be done at least once a
month; more if you change lenses out in the field a lot.