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09-04-2014, 12:40 PM   #31
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That's what I thought but wasn't sure. Thanks!

11-28-2015, 07:00 AM   #32
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When i bought a K3, i wanted to get my S-Type out of my K10D and into my new K3.
i consider myself a patient and careful person.
well... i scratched the screen. :-/

So i ordered a new screen on my birthday, it came today.

I was very happy, although frustrated by the bad online instructions.
And by the fact that they don't write the thickness of the different shims on them.

I had to put it in several times, to find the right combination of shims...
i was super careful, but the third time i've put the new screen in, i scratched it really bad :-0

now i just wanna cry and never take photos again
12-01-2015, 03:14 PM   #33
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QuoteOriginally posted by Bromberger Quote
When i bought a K3, i wanted to get my S-Type out of my K10D and into my new K3.
i consider myself a patient and careful person.
well... i scratched the screen. :-/

So i ordered a new screen on my birthday, it came today.

I was very happy, although frustrated by the bad online instructions.
And by the fact that they don't write the thickness of the different shims on them.

I had to put it in several times, to find the right combination of shims...
i was super careful, but the third time i've put the new screen in, i scratched it really bad :-0

now i just wanna cry and never take photos again
If it is any consolation, the K10D screen would not have fit your K-3. Back to your current situation...The shims they provide are pretty difficult to work with (flimsy, saggy) and there is no indication of size. I cannot help with your scratched screen, but may be of some assistance with shims should you need an alternative to what focusingscreen.com sent you. PM me.


Steve
12-02-2015, 01:16 AM - 1 Like   #34
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QuoteOriginally posted by Bromberger Quote
When i bought a K3, i I was very happy, although frustrated by the bad online instructions.
And by the fact that they don't write the thickness of the different shims on them.

I had to put it in several times, to find the right combination of shims...
i was super careful, but the third time i've put the new screen in, i scratched it really bad :-0

now i just wanna cry and never take photos again
It would simplify things so much if only it was easier to understand or know how many or which shims to use. I too have been messing so much with them, that I ended up scratching.

It's the exact reason why ordering a new focusingscreen wasn't the first thing I did (and still haven't done so) when I got a new camera body.

12-03-2015, 04:57 PM - 1 Like   #35
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QuoteOriginally posted by Zafar Iqbal Quote
It would simplify things so much if only it was easier to understand or know how many or which shims to use.
It requires a master of the dark arts

It also requires some thought as to where the focus plane for the reflex image lies in comparison to the actual focus plane*. There are confusing diagrams all over the Web and perhaps some day I should add my own, but I think a short description might be enough. Here are the points to consider:
  • Most (all?) Pentax dSLRs have a factory shim installed
  • The factory shim is best left in place if at all possible
  • Adding additional shim thickness results in the face of the screen being closer to the lens
  • Moving the focus ring towards infinity results in both the face of the focus screen and the sensor being closer to the lens
  • Your goal is to have the face of the focus screen and the sensor the same distance from the lens
  • You can use magnified live view for determining a reference for critical focus
Having the above in mind, here is how I evaluated shimming when I installed my Katz Eye on the K-3:
  • On tripod
  • High contrast focus target. Should have a vertical line if you are evaluating a split-image screen.
  • Sensor parallel to target
  • Old school manual focus lens (long focus throw is good). I use one of my fast 50s.
  • F/2.8 or wider maximum aperture
  • Target ~20x the focal length from the sensor
  • Use magnified live view to adjust to an accurate fine focus (focus plane at sensor plane)
  • Without touching the lens, change to the optical viewfinder
  • Note whether the split-image matches. If not, determine the direction the focus ring must be turned to make the split match. If towards infinity, you need a thicker shim.
Note that I avoided the using the usual terms of front/back focus. No sense confusing things by adding an additional level of abstraction.


Steve

(If you are using the focusingscreen.com plastic shims, you have my sincerest sympathy. If you would like genuine Pentax shims, PM me. I have a source... )

* There is a common confusion of terms. Focus plane is inside the camera. Plane of focus is somewhere in front of the lens.

Last edited by stevebrot; 12-04-2015 at 11:44 AM.
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