Cleaning mirror and pentaprism on K5

A few days ago I noticed an annoying black spot in the viewfinder and ascertained that it was something on either the mirror or the pentaprism above it. I tried to blow it away with the a blower but it would not budge so I very gently I brushed with a lens brush ( part of the blower) but only succeeded in redistributing the dirt and made it rather worse. I know that Pentax produce a cleaning kit and maybe I should try to get that. How do others tackle dust on the mirror/pentaprism?
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Miles500

Miles you need to be very careful here, I would suggest an artic butterfly or very light soft brush. If you put too much pressure on a mirror you can throw it out of alignment, if you use pentax's cleaning lolipop do so softly.
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Regards Dean - Capturing Creation

Best advice -- IGNORE it.

Dust on the mirror or pentaprism can't affect the image quality of the photos you take. It is purely a cosmetic annoyance at the moment you shoot the picture, but has no lasting effect.

However -- the mirror is front-surfaced and VERY VERY DELICATE. You can scratch it with almost anything. In fact, you may already HAVE by using a brush on it! The focusing screen (which is the part you can touch from inside the camera) is ALSO VERY DELICATE. It is made of plastic and is marred by even the slightest touch.

So -- for best results and camera preservation learn to ignore spots on the mirror or focusing screen!

With regards to focusing screens (and I've ruined a couple trying to get them clean, so I fully concur as to how fragile they can be), I'd be tempted to try an ultrasonic bath if there is a distracting amount of dirt on them.

Using warm, distilled water (so as not to leave mineral residues when the water evaporates) should be perfectly safe, and could well shake loose any particles on the screen. Not tried this myself yet, but fully intend to do so next time my screen gets dirty. Something to consider if you have access to a US bath.

I have found in the passed that cleaning products for focusing screens - even ones specifically marketed as such - can end up effecting the plastic, turning it milky/cloudy, hence why I would limit cleaning to distilled water.

Yes I will try to ignore the specks. It is odd how they suddenly appeared and must have drifted in when I was changing lenses. I must hope that they disappear. Oddly enough I have never had any bother with the sensor itself.
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Miles500

Are you using dust sealed lenses? If you aren't then that is where your dust comes from, the lens parts move and they create an air pump.
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Chris.

A weather sealed ultra wide, is that too much to ask?

http://www.pentaxphotogallery.com/chriside

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Pentax SLR talk FAQ
http://forums.dpreview.com/forums/read.asp?forum=1036&message=23161072

The fact that it moved when you cleaned the mirror may be related to physically turning the camera about. Dust and tiny hairs can get inside the optical view finder system itself and only a service will get them out. My K100Ds suffers from this and it’s a real pain.

Thanks Ian

The mirror is a synch to clean.

I just use a wet clean sensor wipe(swipe) and solution and its been my practice since I've been shooting DSLR's.

Having said that, are you certain the spec is on your mirror? From my experience, mirror dust doesn't usually show-up readily in the viewfinder. However, specs on the focusing-screen would show quite readily.

As for the prism, I've never cleaned one, nor can I say I've had a dirty one either.

However, if yours is dirty, I'd recommend holding-off on trying to clean it in favor of of a Pentax CLA.

Leave the mirror alone. While the surface isn't as delicate as many people make it out to be, it can still be knocked out of alignment pretty easily.

Anything you see on the mirror from the front will not be visible on the focus screen.

Same with the screen. If the dust doesn't come off with a puff from a bulb lower or a squirt of Dust-Off (go ahead and cringe, but it works), then learn to live with it.

Anything you see in the viewfinder will not be visible on the image, and is not something on either the screen or the lens.

In my many years in the industry, I saw more cameras and lenses damages by cleaning than all other reasons for damage combined, and with the sudden fetish of dust paranoia because of sensors rather than film, it is bound to get worse.

miles500 said:

A few days ago I noticed an annoying black spot in the viewfinder and ascertained that it was something on either the mirror or the pentaprism above it. I tried to blow it away with the a blower but it would not budge so I very gently I brushed with a lens brush ( part of the blower) but only succeeded in redistributing the dirt and made it rather worse. I know that Pentax produce a cleaning kit and maybe I should try to get that. How do others tackle dust on the mirror/pentaprism?
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Miles500

Click to expand...

Its true that the dust is cosmetic but its like looking through a dirty window, not nice! If I never cleaned my focus-screen the bottom of the pentaprism above it I would have a view-finder full of debris and contamination. All of our environments are very, very different. What applies to one does not apply to others. Same with where and how you use your dSLR.

Only Visible Dust makes products to clean your mirror, focus-screen and pentaprism. The mirror does not really show dust like the area on and above the focus screen. Although with this being said I have ruined a screen or two by just removing them and not being careful enough. Now with experience I have not ruined one in over three years and many cleanings.

I recommend to go to Visible Dusts site and start reading! Search the subject. You can wet clean your focus-screen (I have) and the cleaning formula puts an anti-static barrier on the focus-screen to help keep dust, debris off. It does work.

You can also use the Arctic Butterfly brush with the special attachment for the focus-screen, mirror and bottom of the prism. I have been one very happy customer. Becuase of this -

I bought this cleaning kit over 3 years ago (724 Travel kit+mirror-focusScreenBrush) for about $200 USA. I have not needed anything else. No swabs, no chemicals, no nothing. I have cleaned my sensor dozens of times (when needed) and focus-screen/mirror many more times as well. My dSLR has not a spot of dust in the OVF nor is there any (visible) on the sensor. Also in more dusty environments always removing dust rather than blowing helps (logically) keep dust out of your dSLR. To me that's a good thing; and a good value.

If your the type who does not like dust in your OVF then I don't know of any other safe (however removing FS is always a risky job) way to remove it other than products from Visible Dust. I have no connections what so ever with them. Remember some contaminates will leave behind a nice oil or water based stain on your focus-screen or pentaprism blowing can't remove; only wet cleaning will! Also you don't have to remove the focus-screen to clean its bottom for a better than nothing cleaning?

The reason to clean the mirror with a brush is to remove dust from it. You won't see the dust in the OVF when on the mirror but when it flies up at high-speed (taking a pic) it 'can' blow the dust thats on it onto the bottom of the focus-screen.

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jamesm007,

http://www.flickr.com/photos/jamesm007/
http://s195.photobucket.com/albums/z77/jamesm700/

Thanks for all the advice. The dust entered last weekend when I was at a nature reserve attempting to shoot some waterfowl with my 55-300. The landscape seemed so nice - reed beds and a distant view of Arundel castle that I switched to my 35 Ltd and that was the fatal moment! Normally I switch lenses often enough with no problem. I am satisfied that the debris which flew in, is on the focusing screen rather than the mirror (which I have incidentally not touched at all with the brush as it appeared to be rather delicate). I will see how I get on and if I should become unduly disturbed, I will investigate one of the cleaning kits mentioned. Thanks again to every one for their help.
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Miles500