K20D - Katz Eye - Focus

CertEdFriday · 01-13-2009, 01:15 PM

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

stevebrot · 01-13-2009, 01:35 PM

Originally posted by CertEdFriday

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

kristoffon · 01-13-2009, 02:01 PM

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.

stevebrot · 01-13-2009, 03:02 PM

Originally posted by kristoffon

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

CertEdFriday · 01-13-2009, 05:52 PM

Originally posted by stevebrot

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...

Matt Miller · 01-13-2009, 08:07 PM

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.

**jbinpg** · 01-13-2009, 10:31 PM

Originally posted by Matt Miller

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

blende8 · 01-14-2009, 02:11 AM

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.

CertEdFriday · 01-14-2009, 10:43 AM

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

dave sz · 01-14-2009, 12:53 PM

Does the k20 have diopter adjustment right above the eyepiece? Maybe you need to adjust that...

CertEdFriday · 01-16-2009, 03:44 PM

Hi thank you for reminding me about that. Tried it and the diopter setting is fine thanks. Just got to do the lens tests!

01-13-2009, 01:15 PM	#1
CertEdFriday Senior Member Join Date: May 2008 Location: UK - Somerset Photos: Gallery \| Albums Posts: 175	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

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01-13-2009, 01:35 PM	#2
stevebrot Otis Memorial Pentaxian Join Date: Mar 2007 Location: Vancouver (USA) Photos: Gallery \| Albums Posts: 42,007	Originally posted by CertEdFriday 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
kristoffon Veteran Member Join Date: Aug 2008 Location: Brazil Posts: 532	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
stevebrot Otis Memorial Pentaxian Join Date: Mar 2007 Location: Vancouver (USA) Photos: Gallery \| Albums Posts: 42,007	Originally posted by kristoffon 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
CertEdFriday Senior Member Join Date: May 2008 Location: UK - Somerset Photos: Gallery \| Albums Posts: 175 Original Poster	Originally posted by stevebrot 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
Matt Miller Veteran Member Join Date: May 2007 Location: Cambridge, Iowa Photos: Gallery Posts: 339	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
jbinpg Site Supporter Join Date: Mar 2008 Location: Prince George, BC Photos: Gallery \| Albums Posts: 3,546	Originally posted by Matt Miller 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
blende8 Veteran Member Join Date: Feb 2007 Location: Bremen, Germany Photos: Albums Posts: 1,521	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
CertEdFriday Senior Member Join Date: May 2008 Location: UK - Somerset Photos: Gallery \| Albums Posts: 175 Original Poster	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
dave sz Veteran Member Join Date: Dec 2006 Location: carpentersville, IL Posts: 693	Does the k20 have diopter adjustment right above the eyepiece? Maybe you need to adjust that...

01-16-2009, 03:44 PM	#11
CertEdFriday Senior Member Join Date: May 2008 Location: UK - Somerset Photos: Gallery \| Albums Posts: 175 Original Poster	Hi thank you for reminding me about that. Tried it and the diopter setting is fine thanks. Just got to do the lens tests!