20d dust in the viewfinder

[wintoid]

I've got a rocket blower on order because my 20d has tons of dust on the sensor, but my question is about dust in the viewfinder. I have one great big glob of dust in the viewfinder. Will squirting the rocket blower through the lens mount shift it, or do I need to find a way in through the eyepiece or something?

[dhbailey]

Most likely it is on the surface that you will be able to blow with the rocket blower through the lens mount. For this you will NOT turn on the sensor-clean function, since the locked-up mirror would be in the way of the viewfinder screen.

For blowing dust off the sensor, you will need to turn ON the sensor-clean funtion. Be sure you have a relatively fresh battery -- don't use one that has been in the final third power-bar for a long time, since you don't want the power to shut off while the mirror is up and your blower might be in the way when it snaps down.

[wintoid]

Thanks David, I'll try that as soon as the rocket blower arrives.