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01-13-2009, 01:15 PM   #1
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K20D - Katz Eye - Focus

Hi,
Just taken delivery of an almost new K20D complete with Katz Eye screen/Opti Brite

I noticed that when using auto focus the camera indicates that my 28-70 is in focus. However the Katz Eye split focus screen shows things to slightly out of focus.

I then did the same exercise with my 300 lens and everything was fine.

Is it my 28-70 lens? Or is it the camera or the screen?

I have read somewhere about ajusting the focus on a K20D, but surely that must affect all lenses...

Any ideas greatly appreciated

01-13-2009, 01:35 PM   #2
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QuoteOriginally posted by CertEdFriday Quote
Hi,
Just taken delivery of an almost new K20D complete with Katz Eye screen/Opti Brite

I noticed that when using auto focus the camera indicates that my 28-70 is in focus. However the Katz Eye split focus screen shows things to slightly out of focus.

I then did the same exercise with my 300 lens and everything was fine.

Is it my 28-70 lens? Or is it the camera or the screen?

I have read somewhere about ajusting the focus on a K20D, but surely that must affect all lenses...

Any ideas greatly appreciated
Most likely the KatzEye is correct.

Manually focus with the KatzEye and take the photo. Check the image to see if it is in focus. Repeat using AF and check again.

Steve
01-13-2009, 02:01 PM   #3
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I have a Katz Eye and I took it out for cleaning once then when I put it back I noticed the same thing - autofocus was right but the screen didn't agree.

It turns out I had mistakenly mounted the focusing screen shim flipped right to left. That shim goes between the screen and its mounting point and is probably adjusted from camera to camera to account for construction fluctuations. The difference in thickness caused the screen to be out of alignment and not work. Once I re-assembled it correctly everything was fine.

So investigate a possible mistaken assembly.
01-13-2009, 03:02 PM   #4
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QuoteOriginally posted by kristoffon Quote
I have a Katz Eye and I took it out for cleaning once then when I put it back I noticed the same thing - autofocus was right but the screen didn't agree.

It turns out I had mistakenly mounted the focusing screen shim flipped right to left. That shim goes between the screen and its mounting point and is probably adjusted from camera to camera to account for construction fluctuations. The difference in thickness caused the screen to be out of alignment and not work. Once I re-assembled it correctly everything was fine.

So investigate a possible mistaken assembly.
Note that the mounting procedure and setup are a bit different between the K20D and the K200D.

I would test the screen accuracy first with the lens in question.

Steve

01-13-2009, 05:52 PM   #5
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QuoteOriginally posted by stevebrot Quote
Note that the mounting procedure and setup are a bit different between the K20D and the K200D.

I would test the screen accuracy first with the lens in question.

Steve
Thank you for the advice. I will look at doing the comparisons first. Not too keen on messing with the Katzeye - dont want to damage anything...
01-13-2009, 08:07 PM   #6
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The screen is installed correctly. There is no shim for the K20D. Most likely it's just a slight mis-focusing by either the lens, the camera, or the combo. If you test the lens at different focal lengths and find it seems to be off the same for all, you can adjust the autofocus for that lens only. The K20D stores individual focus adjustments for several lenses. It does not apply the same adjustment to all lenses.
01-13-2009, 10:31 PM   #7
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QuoteOriginally posted by Matt Miller Quote
The screen is installed correctly. There is no shim for the K20D. Most likely it's just a slight mis-focusing by either the lens, the camera, or the combo. If you test the lens at different focal lengths and find it seems to be off the same for all, you can adjust the autofocus for that lens only. The K20D stores individual focus adjustments for several lenses. It does not apply the same adjustment to all lenses.
Unless you tell it to: Custom Settings -> 35. AF adjustment -> On -> [Apply All] [Apply One]

See page 106 of the manual.

Jack
01-14-2009, 02:11 AM   #8
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The main problem with these focussing screens is that the light path for the screen and for the AF system is different. Even a very slight difference in thickness or positioning of the screen will be noticed.
Some people have therefore experimented with thin pieces of tape added to the border of the screen. But it's very fiddly.

I have a split prism screen in my K10, too, and it is not 100% perfect. But this is not so important. I just know that I have to adjust the focus very slightly to the left, to get it perfect.

01-14-2009, 10:43 AM   #9
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Working away at the moment so will have to wait until the weekend to try out these suggestions. I knew there was a way to correct the focus within the camera - just haven't had the time to go into the manual and find out - sot thanks for the page ref etc.

Regards

David
01-14-2009, 12:53 PM   #10
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Does the k20 have diopter adjustment right above the eyepiece? Maybe you need to adjust that...
01-16-2009, 03:44 PM   #11
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Hi thank you for reminding me about that. Tried it and the diopter setting is fine thanks. Just got to do the lens tests!
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