Dust on ,my focus screen

I've got an annoying piece of something on my focus screen, I assume it's that as it shows in the viewfinder but not on the images.

Is there a way to get rid of it? Blow it off maybe?

Rocket blower.

Beg to differ John,
Rocket blowers just move the problem, usually top somewhere less accessible.
Arctic Butterfly every time, for any detritus.

Davex.

You don't use an Arctic Butterfly on focusing screens and mirrors. I have found holding the camera facing downwards spots in the viewfinder system can be removed easily with a rocket blower.

As regards the sensor, the built in dust removal system works most of the time and a rocket blower the rest. I have not physically cleaned a sensor on a DSLR, ever, and the first one I had was some time ago with the *istDS.

Thanks for the advice, I'll give it a puff with the blower!

I've got dust behind the focus screen before. Lean the camera over Karl and there is a little switch which can click the screen out. Use the blower and click the screen back in place.

I also use it on the mirror and focusscreen, i doubt the little bit of pressure will do any harm, the mirror experience a lot more forces when it's slammed closed and open....

The focusing screen is very soft plastic and should not be touched. The mirror mechanism is a very highly precise bit of engineering that should not be touched, lest it gets pushed out of position.

If the mirror isn't precisely in position your images will have a focus error.

This is one of the basic guidelines for handling any SLR or DSLR.

Thanks for the help. Happy to report that the offending particle blew off.

But come on, the mirror is basicly slammed open and close so how can that tiny bit of force you might apply with the brush move it around... if it does i would sent it back to pentax since i wouldn't trust it

It isn't slammed open and closed Stefan, it's a precision mechanism that can be easily knocked out of balance. In addition, it's a front surface mirror and the coating is also fragile.

So the forces you apply with the brush are greater than the forces when the mirror moves?

Is sure believe you that it's precision mechanism and fragile but i don't believe it's that fragile that the forces of the brush will actually do any harm unless you are using a hard brush of course but we are talking about the butterfly now and that's a soft brush. You don't even have to press the hairs against the mirror since it's the static charge of the hairs that do the work so you have to ever so lightly just "caress" the mirror once, a good puff of air might even result in a higher force on the mirror.

You'll have to decide what you do for yourself, but to be honest it discourages me from buying second hand DSLRs that some users do seem to be over-zealous in their treatment of the presision mechanisms.

Well you can always get the brush visibledust (articbutterfly) make for cleaning the mirror and focusing screen but i've no idea what the difference is between the normal one?
http://www.visibledust.com/products3.php?pid=603

I totally agree with John's point of view. Never touch a front surface mirror with anything! It is really vulnerable.

And any forces applied to a mirror apart from the pivoting around its support axis may well upset the alignment.

I think you overestimate the "slamming" forces, Stefan.