Focusing screen is off

[mulanrouge]

My K100D was purchased used with what I believe to be a 45-degree Chinese split focusing screen. I have finally taken the time to confirm that it is not my eyesight, but the focusing screen that is off. My photos are blurry when the split screen is aligned. The split screen is misaligned when it takes focused pictures while in Auto mode (the camera beeps), both in AF and in MF . Any tips on how I can fix this? Please and thank you.

[Kguru]

If you search previous threads you should find quite a few on this topic. Briefly here, the surface of the focusing screen has to be at a certain exact plane for accurate focus when aligned; it is adjustable by using very thin shims under the screen where it sits onto the holding frame. You need to determine whether it's front- or back-focus when aligned then decrease or increase the shim thickness accordingly. If need to reduce shim yet it's already minimum (=no shim) then tough luck, like in my own case

[jlamorie]

I had just purchased one of the 45 degree split screens a few months ago and I had the same problem with focusing and light metering. It was disappointing and a waste of money. I was replacing what I thought was my old split screen but had actually replaced the original Pentax screen and I was blown away with the proper light metering, especially on manual lenses and there was no problem focusing on my subject and it was brighter as well. My camera is the K200D but it sounds like the same scenario. My advice is to purchase the original Pentax screen and avoid any compatibility issues.

[c a sugg]

I had just purchased one of the 45 degree split screens a few months ago and I had the same problem with focusing and light metering. It was disappointing and a waste of money. I was replacing what I thought was my old split screen but had actually replaced the original Pentax screen and I was blown away with the proper light metering, especially on manual lenses and there was no problem focusing on my subject and it was brighter as well. My camera is the K200D but it sounds like the same scenario. My advice is to purchase the original Pentax screen and avoid any compatibility issues.

You can change screens with the K200d?

[jlamorie]

Yep, It's a little finicky but I've done it numerous times. To see how it's done, Google "changing Pentax focusing screens" on youtube. Also, the screen must be compatible with the K200d. I've purchased 2 chinese knock offs from different suppliers and one was ok to good and the other was garbage. I'd advise doing some research.

[wildlifephotog]

Or make your own from a ME Super screen. I'm currently using a cut down Yashica FX-3 screen in my K200D with perfect results. Even the facory shim was correct for it.

[reeftool]

I purchased a 45 deg split screen which was very poor quality. The split prism was on a different angle than the rest of the screen and was almost impossible to focus. I sent it back with the promise of a replacemant but haven't heard from them or received a replacement in 3 months. For $23 it was worth the risk as some folks have been very happy with their screens. Mine was junk. Save yourself some grief, buy a Katz Eye or the origional from Pentax.

[WheresWaldo]

In most of these cases there are very easy resolutions.

1. Most of the cheap Chinese made screens are not very good about quality control, they may also not be as cleanly cut as some of the more expensive focus screens.

2. Almost all front/back focus issues can be solved with the use of shims, unless you have an issue with you camera hardware. Please note that it is not just the exact location of the focus screen it is also the thickness that affects view.

3. Changing focus screens does not affect auto focus, it uses a different mechanism.

4. Every focusing screen that is not plain matte will effect metering, usually only spot metering, and in different ways. It is up to each of us individually to learn how to exploit these differences.

5. Sometimes focusing with a screen that has an aid, whether micro prism, split image or both, is infinitely faster/easier than the standard OEM matte screen.

6. There are documented problems with manual lenses and the standard matte screens, so saying that it is better is not 100% accurate.

Back to the OP's question, you need to determine which way the screen is off. Here is a thread that shows a easy way to test by using common household items, a tripod and your fastest lens. http://www.pentaxforums.com/forums/f...ens-align.html, starts as a discussion of LensAlign but shows how you can 'make' your own. Focusingscreens.com does have a page outlining the use of shims to fix front/back focus here; Focusing Screen--How to adjust focusing screen--.

I have used the information presented here to correctly assess and correct manual focus errors introduced by third party focusing screens. In all cases even the OEM screen was off of precise focus, now every camera I have is less than 1 centimeter off (that's less than .4 inches for the metric impaired). I have three Pentax cameras each with a different screen, in one K20D the OEM shim had to be removed and replaced by a thinner shim as well as a shim added underneath. My second K20D just needed a shim added underneath the screen. My GX-1S only needed the screen and no shims to be focus accurate.

[tomwil]

Or make your own from a ME Super screen. I'm currently using a cut down Yashica FX-3 screen in my K200D with perfect results. Even the facory shim was correct for it.

Really curious ... I have a ME Super ... how would I cut down the screen? Scissors, grinder, file, or what?

[wildlifephotog]

I use a 1" belt sander. I use frosted scotch tape to cover the screen. I then can draw lightly the lines to sand to. If you don't squeeze the tape while working, it peels off nicely.
Here is where I got the idea for doing mine.
greyhoundman's ramblings: October 2006

[AMBIVALENCE]

why people only use ME focusing screens? =/
can i use other camera?

[wildlifephotog]

I used a Yashica FX-3 2000 screen in my K200D. The screen needs to be the same thickness as the Pentax screen.