The numerous discussions on sensor cleaning on this group prompt me to ask the following. Has anyonone using the blower method experienced problems with debris being blown onto the focussing screen's upper surface between the screen and the pentaprism? When using a child's ear-syringe as a blower many years ago on the mirror of my Minolta film cameras, I would sometimes get "lint" into that area causing it to be visible (and highly annoying) through the viewfinder. I haven't seen anyone on the groups mention this and wonder if the air pressure produced by "rocket" blowers, etc. is less than I was using. Or perhaps raising the mirror effectively "seals off" the edges around the viewing screen in a DSLR. I have been reluctant to use a blower on my DSLR because of that nagging fear.
Hi Don, the focusing screen on DSLRs can be removed, they are held in by a spring keeper. Many people change their focusing screen for one that has micro-mesh or split D range finder style screens for much easier manual focusing. There are lots of videos on YouTube showing their removal and installation of a screen like the KatzEye brand. I was thinking about changing mine for use with my 50 f/1.2 but after playing with that lenses for a few weeks I realized that it is not quite as good optically as my current fast portrait lenses. Stan St Petersburg Russia
What has not being mentioned is that you need a professional photo blower. A blower like this one that has an inlet check valve to prevent lint and dust to enter into the sensor you are trying to clean.