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Pentax K200D Focus Screen Removal
Posted By: Darley, 11-13-2013, 09:48 AM

If you can see dark spots in the viewfinder of your DSLR they are most likely specks of dust on the mirror or focusing screen. Usually these specks of dust can be removed with a brush or pad, but occasionally they get behind the focus screen and the only way to clean them off is to remove the screen. You may also want to replace the screen with a diagonal split focus screen for easier manual focusing. I searched everywhere for a clear guide on how to remove the screen from my Pentax K200D and couldn't find one that gave me all the information I needed, so I decided to work it out for myself and then write my own guide. This is my method and I'm sure other people have their own, but this worked for me and I can now actually see the images I'm trying to capture!

Unless you have back-up cameras I suggest buying a focus screen before attempting this for the first time, which you may well have done anyway because you want a split screen for manual focusing. It is not a difficult process but it does require patience and a steady hand. Go at it like a bull in a china shop and you could do a lot of damage, so if in doubt get someone else to do it for you. or practice on a cheap old camera first.

Assemble the following tools and equipment. You do not need to buy specialist tools if like me you have various things lying around or can make your own. You will need some basic cleaning gear, a pair of precision tweezers and a small hook - I found this in an old sewing basket, I think it's for pulling threads of fabric but can't remember what it's called! You could also make a hook out of a piece of stiff wire.

Note the Pec Pad. Cleanliness is essential. Use only high quality Q-tips / cotton buds and fine natural fibre brushes. You will need a lot of Q-tips - use once only and don't use the end you hold on delicate surfaces like focus screens or you may contaminate the surface you're trying to clean.





I use Isopropyl Alcohol and Residual Oil Remover for cleaning cameras and lenses - they will do for just about everything. The air duster is NOT for use on the inside of your camera, it is for cleaning brushes and external parts. I try not to use a blower in the mirror box as dust will go where air goes, and you cannot control the direction of the air. Only use it for moving large particles so they can be grabbed with a sticky pad or cotton bud.



Close-up of the hooked tool. This one is slightly too large but with care I managed to get it to work. The tip should ideally be no more than 1mm across. I know this looks dirty but it was cleaned with Isopropyl before use. I wouldn't recommend using something with such a flaky surface on a very expensive camera!



Use the canned air duster to blow all dust from the brush. Do the same with any tools you intend poking into the insides of your camera. All items should be laid out on a clean, lint-free cloth. Flat, smooth surfaces allow dust to be easily disturbed so unless you have a high-tech air filtration system I suggest an old (many times washed) table cloth or similar - give it a good shake outside before and after use.



Remove lens (obviously) and hold camera so you can see the focus screen which is above and to the rear of the mirror. I tried from every angle to show the catch that you need to hook on to but it's impossible to photograph without help! It lies behind the metal frame and is accessed through the slot shown in these two images. Don't worry, you will see the catch later when the screen is removed.




Push the hook through the slot and latch onto the frame, then pull gently outwards (i.e. downwards as seen from the top of the camera).



Close-up view of the part you need to hook on to. Arrows show direction of travel.



I probably should have done this earlier but anyway ... fold up a clean PecPad and lay it over the mirror to reduce the chances of dropping dirt on it, or worse still dropping a metal tool on it.



Showing the relevant parts. The copper-coloured metal shim is best left in place as it is difficult to line-up. You will need to tilt the camera so the shim falls back into place but the screen remains accessible. The screen is removed by gripping the tab with the tweezers and CAREFULLY pulling it out. If you're a hamfisted oaf it might be better to let someone else do this.



Lay the focus screen with the inside surface (i.e. the side you can't get to when the screen is in the camera) facing up, and use a blower to remove dust. If you can still see dust, use a soft brush but do NOT apply firm pressure. If you can't easily brush it off, go to the next step.



Apply one drop of Residual Oil Remover (ROR) to a cotton bud.



GENTLY roll the tip of the bud across the screen, turning it as you go so as to not to just move dirt around. The ROR should just evaporate - if it doesn't, you used too much! Try blowing to dry it. Don't turn the screen over and clean the other side! Turning it over will just contaminate the surface you just cleaned. You can clean the other side once it is back in the camera. At this stage speed is of the essence - replace the screen before it gets dirty again.



Back in position. This can be much more difficult than removing it, especially if the shim has fallen out. Take your time and satisfy yourself that everything is lined-up before pushing it back into place.



Use something soft to push the assembly back - it should just click into place with very little effort. If it doesn't, make sure everything is aligned properly and try again. I don't worry about cotton fibres - they're large enough to see and remove easily. Better than scratching the screen or mirror.


You can now clean the external surface if necessary, as well as the mirror. Use the soft brush to flick dust out and away from the internal parts, and then the cotton bud with a little ROR if necessary.

Finish by removing all dust from the mirror box with a brush, sticky pad or Q-tip / cotton bud. A drop of Isopropyl on a cotton bud will do for cleaning the internal plastic surfaces (not the mirror or shutter mechanisms!) and lens mount. Keep dust and dirt away from these areas and you shouldn't have to clean the mirror or focus screen often. Mine was bought used and was filthy - I could barely see light through the viewfinder! The observant amongst you will notice it still looks a bit hazy and it really needs replacing, but it will do for now.

I will say this again - do NOT blow into this part of the camera. It doesn't matter how you hold the camera, dust will go up, down, and sideways along with the flow of air, and probably end up in the most inaccessible places. If you have a small vacuum cleaner, try sucking dust out as you gently agitate it with a brush.

Last edited by Darley; 11-13-2013 at 10:06 AM.
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11-14-2013, 12:52 PM   #2
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Nice job!
I also tried to search a step-by-step guide few moths ago with bad luck. I was replacing to split screen, using a broken ME Super as organ donor, cut the screen with dremel. Well, ended up with working but dirrrrty screen, otherwise ok.
Managed to switch it with just tweezers and small screwdriver, though...
11-14-2013, 12:58 PM   #3
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Amazing shots of all the tools and an internal camera parts - I always struggle to get this sort of shots if I want to show anything inside the camera --manntax
11-14-2013, 01:20 PM   #4
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QuoteOriginally posted by manntax Quote
Amazing shots of all the tools and an internal camera parts - I always struggle to get this sort of shots if I want to show anything inside the camera --manntax
It's hard holding stuff in one hand and trying to photograph it with the other, but I have a secret weapon called a *cough* Canon SX160IS which has an amazing macro mode. It's probably better than many DSLR macro lenses.

11-14-2013, 01:22 PM   #5
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QuoteOriginally posted by manntax Quote
Amazing shots of all the tools and an internal camera parts - I always struggle to get this sort of shots if I want to show anything inside the camera --manntax
I meant to add some shots of the swabs I ended up using to clean the screen a second time - they're made of some sort of foam rubber and designed for delicate electronic parts, and clean without leaving any residue. Cotton buds are ok but can leave smears.
11-14-2013, 01:37 PM   #6
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QuoteOriginally posted by Darley Quote
but I have a secret weapon called a *cough* Canon SX160IS which has an amazing macro mode.
wow no doubt about that ! worked perfectly - thanks !
--manntax
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