[longbo]

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While experimenting with a 42mm screw in lens I managed to get some debris on the focusing screen of my KP. The worst bit looks like a large seagull flying across the top of the frame and there are various other smaller bits. I've tried blowing 'em with my hurricane blower, but to no avail.

I started to look into removing the screen to clean it, but cleaning these things looks problematic in itself? So I then thought about replacing it, but screens I can see advertised here in the UK, such as the ME-60, MF-60, MI-60 or ML-60 [all available with a fitting kit from Bristol Cameras], although they appear physically to fit the KP, have designs that are totally different from the currently fitted screen.

I'd welcome advice from those with experience of this issue.

Thanks.

[Not a Number]

The crud could have gotten between the focus screen and prism.

Removing the screen is usually simple enough. You need to push the spring catch away from the screen frame and then the frame and screen will swing out on a hinge. You may not need to remove the screen but leave it in the frame and blow off the exposed prism and screen.

I recommend using something wooden to release the catch or if you use metal tools like a screwdriver or tweezers to cover the tips with some tape to minimize chances of scratching the screen.

[Crooski]

Pretend to switch the focus screen, use a tweezer and don't touch the focus screen with your hands

[photogem]

Steps:
1. Take out the focusing screen as shown HERE
2. Have another person holding the screen while you have a look through the viewfinder to see if there is anything left in the prism.
If not then:

3. Hold the screen tight on its sides (but avoid touching the front and back sides!)

4. Hold it into the stream of a vacuum cleaner. In 99% of all cases I got it clean with that method.
But really hold it tight! Fear is your enemy there!


If there is any debris in the prism, before I got a prober ESD vacuum cleaner, that was the method I successfully applied:
Modify vacuum-cleaner for safe dust-cleaning your Pentax (anti-static ESD) - PentaxForums.com

Read the last comment to make sure the wiring in your home is save. Usually in the UK that is the case, 2-prong outlets are not allowed in the UK since long time:
https://www.quora.com/Electrical-Outlets-Why-has-the-UK-always-had-3-prongs-...-and-no-ground

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Last edited by photogem; 11-24-2021 at 06:53 AM.

[tokyoscape]

If you go for a cleaning route.
Be very gentle. Better do not touch the front and back parts of the focus screen at all. The surface can be easily scratched. Only hold on its handle, the part with model number printed on, or on its sides.

[photogem]

Better do not touch the front and back parts of the focus screen at all.

I'd go much further: NEVER touch the front and back parts! It is easy + safe to hold the focusing-screen on the sides.
To get it out: Tweezers at the extension.

[longbo]

Thanks for these suggestions - I'll just have to pluck up courage to access the screen!

If I were to change the screen, does anyone have suggestions as to which type to use? Can anyone point me at an article that discusses screen types - I do have a couple of manual lenses that might benefit?

Thanks.

[photogem]

Thanks for these suggestions - I'll just have to pluck up courage to access the screen!

If I were to change the screen, does anyone have suggestions as to which type to use? Can anyone point me at an article that discusses screen types - I do have a couple of manual lenses that might benefit?

I have other Pentax bodies (K5) for different screens, there are several available from focusingscreen.com:
Focusing Screen

For fast primes such as the SMC Pentax A-50/1,2 or 1,4, similar Takumars etc. option 1:
Focusing Screen


review here:
FocusingScreen.com S-type screen reviews - Pentax Camera Accessory Review Database

Not to use the version with AF-markings!


For the split-image version:
Focusing Screen
Focusing Screen

but a Katzeye with Optibright is better, yet hard to find.

Anyway: A K5 is good enough imo, you don't need the better AF for those lenses, so why even a K5IIs or K3?!
But I would not one in my KP, there I want AF at its best.

Get this one, it is better imo than the original:
PENTAX Focusing Screen ML-60 Grid type AF Divided Matte for K3 K5 K7 from Japan | eBay
PENTAX ML-60 AF Divided Matte (K-5, K-7) reviews - Pentax Camera Accessory Review Database
Since the K7 all screens for K7/5/3/30/50/K-S1/S2/70 and KP are the same. I don't know about the new K3III.
Possibly the same as well.

The original one:
PENTAX Focusing Screen MF-60 Standard AF Framed Matte for K3 K5 K7 from Japan 4961333155736 | eBay

[longbo]

Again, thanks to all for your help. I finally bit the bullet and lifted the screen out and used my blower on both sides. Now it's back in, there are a couple of dust specks, but nothing like before - certainly, the seagull has taken flight.

Thanks to Notanumber - some of the crud was indeed on the prism side. Also to Crooski and photgem for their instructions on removing the screen and finally to photogem again for the details on the various available screens. This is a brilliant forum - all within 24 hours!