Sensorbrush, is it good to clean dust on top of the mirror?

[dRebelXT]

I think there is a large dust on the glass plate above the 45 degree mirror.
I see it in the viewfinder, but not in pictures. What is the purpose of this
piece of glass? Is it ok to brush it with a very small sensorbrush? ;p

 

[vince123123]

The "glass plate" is the focussing screen - you use this to see that your images are in focus or not, or for that matter, to see the image in the first place. Light from your image comes through the lens, bounces up the mirror and is projected onto the screen.

I think there is a large dust on the glass plate above the 45 degree mirror.
I see it in the viewfinder, but not in pictures. What is the purpose of this
piece of glass? Is it ok to brush it with a very small sensorbrush? ;p

 

[LittleWolf]

I think there is a large dust on the glass plate above the 45 degree mirror.
I see it in the viewfinder, but not in pictures. What is the purpose of this
piece of glass? Is it ok to brush it with a very small sensorbrush? ;p

For its function, see the post by vince123123. Two things to add: First, the focusing screen is easily scratched. Also, the screen has a textured surface which gives it a certain roughness.It will readily pick up more dust/dirt/fibres from whatever you use to clean it with. Second, dust on the focusing screen doesn't affect the pictures.

 

[+evenstar]

Use a blower