Need help for a recently bought K100D with a custom focusing screen

mikerigel · 06-23-2011, 01:04 PM

I just bought a used K100d as a backup body but it came with this custom focusing screen installed, see my drawing below.

The problem is it doesn't work, when the autofocus beeps and I take the shot, the screen is all blurry, but the photos are nice and sharp.
And of course, when I manually focus to where the split screen in the middle is perfect, the photo is blurry.
So I can't manual focus at all now with this screen, pretty ironic.. isn't it what they are made for ?

I am unfamiliar with those screens, would anyone have some advice on something I can do ? Is the screen bad ? I really don't feel comfortable with changing it myself.
Thanks

JeffJS · 06-23-2011, 01:25 PM

The screen may be in upside down if it doesn't have the alignment tab on it. I had one of those cheapo Chinese screens for my K10d and what you describe is what happened the first time I put it in the camera. The bracket holding it in place may have come loose for some reason. -OR- the screen needs to be shimmed.

There are a few videos on Youtube on changing the focus screens in Pentax dslrs and in this respect all the cameras are basically the same. I'm assuming of course you have set the Diopter for your eyesight.

Aegon · 06-23-2011, 01:31 PM

Nice drawing.

The position of the focusing screen in the light path effects its accuracy. Small changes in position cause correspondingly large changes in accuracy. Position adjustments are usually done by adding shims of the proper thickness. Determining the proper thickness may take trial and error. Common DIY shim materials include post-it notes, scotch tape, or whatever else you can find that is uniformly thick, adjustable, and likely to last for a while.

Do you know where the screen fits? Are you comfortable shimming it? =

mikerigel · 06-23-2011, 01:32 PM

Thanks for your input. How can you tell if the screen is upside down ? Any markings I should look for ? I just checked the bracket holding it and it feels tight.
I did set the diopter, I wish it was the problem!

mikerigel · 06-23-2011, 01:38 PM

Thanks for your help. I guess I need to look on youtube and get a feel for what needs to be done. I don't mind trying, I just need to find out where to put the shims...
So you think this is most likely the problem ? I guess it could be worst.

Originally posted by Aegon

Nice drawing.

The position of the focusing screen in the light path effects its accuracy. Small changes in position cause correspondingly large changes in accuracy. Position adjustments are usually done by adding shims of the proper thickness. Determining the proper thickness may take trial and error. Common DIY shim materials include post-it notes, scotch tape, or whatever else you can find that is uniformly thick, adjustable, and likely to last for a while.

Do you know where the screen fits? Are you comfortable shimming it? =

JeffJS · 06-23-2011, 01:44 PM

Originally posted by mikerigel

Thanks for your input. How can you tell if the screen is upside down ? Any markings I should look for ? I just checked the bracket holding it and it feels tight.
I did set the diopter, I wish it was the problem!

If there is no tab, flip the screen over. The bracket is held in place via a little clip in front of the screen housing. Pushing carefully on that tab will release the door that holds the screen in place and allow it to drop. With any of the three suggestions I gave, you will have to do this.

You Tube

As I said, I believe they are all set up the same way so the actual model shouldn't matter here.

mikerigel · 06-23-2011, 02:05 PM

Thanks for the link, I got the screen out, it has a tab on the right, but I still flipped it over since there's room for the tab on the left.
And it works! so thank you guys!
Now I don't have to yell at the seller!

06-23-2011, 01:04 PM	#1
mikerigel Veteran Member Join Date: Sep 2006 Location: Florida Photos: Gallery Posts: 354	Need help for a recently bought K100D with a custom focusing screen I just bought a used K100d as a backup body but it came with this custom focusing screen installed, see my drawing below. The problem is it doesn't work, when the autofocus beeps and I take the shot, the screen is all blurry, but the photos are nice and sharp. And of course, when I manually focus to where the split screen in the middle is perfect, the photo is blurry. So I can't manual focus at all now with this screen, pretty ironic.. isn't it what they are made for ? I am unfamiliar with those screens, would anyone have some advice on something I can do ? Is the screen bad ? I really don't feel comfortable with changing it myself. Thanks

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06-23-2011, 01:25 PM	#2
JeffJS Inactive Account Join Date: Aug 2008 Location: Michigan, USA Photos: Gallery \| Albums Posts: 7,484	The screen may be in upside down if it doesn't have the alignment tab on it. I had one of those cheapo Chinese screens for my K10d and what you describe is what happened the first time I put it in the camera. The bracket holding it in place may have come loose for some reason. -OR- the screen needs to be shimmed. There are a few videos on Youtube on changing the focus screens in Pentax dslrs and in this respect all the cameras are basically the same. I'm assuming of course you have set the Diopter for your eyesight.

06-23-2011, 01:31 PM	#3
Aegon Site Supporter Join Date: Jan 2008 Location: Portland, OR Posts: 1,416	Nice drawing. The position of the focusing screen in the light path effects its accuracy. Small changes in position cause correspondingly large changes in accuracy. Position adjustments are usually done by adding shims of the proper thickness. Determining the proper thickness may take trial and error. Common DIY shim materials include post-it notes, scotch tape, or whatever else you can find that is uniformly thick, adjustable, and likely to last for a while. Do you know where the screen fits? Are you comfortable shimming it? =

06-23-2011, 01:32 PM	#4
mikerigel Veteran Member Join Date: Sep 2006 Location: Florida Photos: Gallery Posts: 354 Original Poster	Thanks for your input. How can you tell if the screen is upside down ? Any markings I should look for ? I just checked the bracket holding it and it feels tight. I did set the diopter, I wish it was the problem!

06-23-2011, 01:38 PM	#5
mikerigel Veteran Member Join Date: Sep 2006 Location: Florida Photos: Gallery Posts: 354 Original Poster	Thanks for your help. I guess I need to look on youtube and get a feel for what needs to be done. I don't mind trying, I just need to find out where to put the shims... So you think this is most likely the problem ? I guess it could be worst. Originally posted by Aegon Nice drawing. The position of the focusing screen in the light path effects its accuracy. Small changes in position cause correspondingly large changes in accuracy. Position adjustments are usually done by adding shims of the proper thickness. Determining the proper thickness may take trial and error. Common DIY shim materials include post-it notes, scotch tape, or whatever else you can find that is uniformly thick, adjustable, and likely to last for a while. Do you know where the screen fits? Are you comfortable shimming it? =

06-23-2011, 02:05 PM	#7
mikerigel Veteran Member Join Date: Sep 2006 Location: Florida Photos: Gallery Posts: 354 Original Poster	Thanks for the link, I got the screen out, it has a tab on the right, but I still flipped it over since there's room for the tab on the left. And it works! so thank you guys! Now I don't have to yell at the seller!