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12-27-2011, 11:04 AM   #331
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QuoteOriginally posted by jolepp Quote
...but then Focusingscreen.com's instruction page (here) mentions 0.25mm right under the picture of both kinds of shims (?). Be that as may it seems that both kinds of plastic shims result in a bit of back focus for me while the stock metal shim gives a bit of front focus with the Porst 55mm 1:1.2. I think what I need is something like 0.3mm.
An El-Cheapo vernier caliper would seem to vouch for all the shims that came with the screen to be 0.25mm while the stock would be 0.4mm (but then the caliper is rather crappy and this would be a micrometer job anyway).
If the shim is thinner than the correct value, you get back focus, if the shim is thicker than you get front focus. So your experience with the stock shim (0.40mm) is as expected.
Focusingscreen delivered to me: 3pcs of 0.15mm shim and 1pc of 0.25mm. The difference between 0.15 and 0.25 is visible (touchable) without measurement.
So that two pieces of 0.15mm together (from the bag where you have 3pcs) could be the right value. It's exactly same as my K5.

12-28-2011, 01:20 PM   #332
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QuoteOriginally posted by Jan67 Quote
If the shim is thinner than the correct value, you get back focus, if the shim is thicker than you get front focus. So your experience with the stock shim (0.40mm) is as expected.
Focusingscreen delivered to me: 3pcs of 0.15mm shim and 1pc of 0.25mm. The difference between 0.15 and 0.25 is visible (touchable) without measurement.
So that two pieces of 0.15mm together (from the bag where you have 3pcs) could be the right value. It's exactly same as my K5.
That should work for 0.30mm then (the vernier caliper I tried on them is crappy so 0.15mm is quite possible ). Focusingscreen.com could be more informative about this though, now the only figure I could find was 0.25mm and it was unclear to what exactly that applied to . 1x0.25 + 3x0.10mm shims would probably make even more sense (0.20 = 2 x 0.10, 0.25 = 0.25, 0.30 = 3 x 0.10, 0.35 = 0.25 + 0.10)?
12-28-2011, 11:33 PM   #333
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Possibly a dumb question, but here goes:
I have a canon-converted high contrast screen for K5 from focusingscreen.com, the same as in the photos above.
I have mine in the camera with no shims at all.
When talking about front/back focusing I assume you are referring to difference between what the eye sees as focused through the viewfinder, and the actual recorded image being focused in front or behind that point. Right?
I ask because as I said, I use no shims, and my tests seem to show that what I see through the screen, and the resulting photograph are as identical as I can perceive.
http://oh-hi.info/tech/00043873a-768px.jpg
*However* I did notice that the camera's focus confirm lights seem to front focus. I tend to ignore it so much that I have recently turned it off entirely, so maybe it was actually back focusing. But in either case, the focus confirmation lights were incorrect when visually and photographically everything is working correctly...without any shims.
Are the shims so that I can see focus correctly? Or so the focus confirmation can see it correctly? Or both?
Does this mean I got lucky with not needing shims? or does this mean everyone else didn't get so lucky? Or that I need my eyes tested :)
... or that they are putting their screen in backwards and thereby needing shims to compensate? (thats not really a serious question, but it did appear that they could go in both ways when last I checked)
12-28-2011, 11:42 PM   #334
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An interesting question. I can't see how any change in shim should be necessary if the screen is accurately transmitting optical data (unless it is changing it). Then again I'm not an expert in these things. I think I should just keep my trap shut and do some research.. lol

I am interested to know if the screen changes the eyepiece magnification though. Mine should arrive tomorrow so I guess I'll find out for myself soon enough.


Last edited by bossa; 12-28-2011 at 11:56 PM.
12-28-2011, 11:59 PM   #335
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QuoteOriginally posted by BETLOG Quote
Possibly a dumb question, but here goes:
I have a canon-converted high contrast screen for K5 from focusingscreen.com, the same as in the photos above.
I have mine in the camera with no shims at all.
...
So you removed the factory shim (0.40mm, usually) too? (I would not be too surprised if the focus was good with that as in my case the closest to correct shim would seem to be 0.35mm atm ). Also, I suppose it is worth pointing out that the shims affect what one sees on the screen, the AF sensor (and hence focus confirmation) should be fully independent of the shims as the sensor sits under the mirror, at the end of an optical path of its own.
12-29-2011, 01:05 AM   #336
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QuoteOriginally posted by jolepp Quote
So you removed the factory shim (0.40mm, usually) too
No. Good point. I have not removed nor replaced any shims.
So assuming the supplied shim is actually 0.35mm, and the stock shim is 0.4mm, and what Jan67 said above re: front/back focusing due to shim thickness: then without replacing the stock with the supplied shim, I should have a shim that is 0.05mm too thick, and therefore I should be very slightly front-focusing.
Hmm, that seems to correlate with the image I linked. Difficultto be sure though, so it's time to do a more refined test methinks.
12-29-2011, 02:49 AM   #337
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With the FF screen it would be impossible to put it in backwards, since it has a tab. There are manufacturing variations, that's why there is a need for shims.

So you got lucky. Also the screen doesn't transmit the image, it's projected onto the screen and you view it through the pentaprism/viewfinder.


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12-29-2011, 03:11 AM   #338
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QuoteOriginally posted by Nuff Quote
With the FF screen it would be impossible to put it in backwards, since it has a tab
So does the APS-C one. I just inspected the frame that holds it with a loupe, and I see that it would be impossible, or very difficult to put the screen in backwards. I was just joking anyway :]
QuoteOriginally posted by Nuff Quote
So you got lucky
Twice now it seems. Once with the split hemisphere one, and now with the naked screen. Nice.

01-02-2012, 06:53 AM   #339
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I've read this thread right through and thought about buying one of these S screens for my K-5, but I have to ask this question.

Because I have a few manual lenses and I often do low light photos, indoors, macro, astro (600mm or more) etc, would I find this screen too dark to use be it small or large apertures ?

What I mean is, I've read some mention it being darker with the aperture closed down, but how much darker ?
I use 2 pairs of glasses to see as it is.




And for those changing their screens this might help. With my *ist-DL I found it best to open the screen frame with the camera on it's back and a tissue covering the mirror (the frame will spring open and hit the mirror), and reassemble the screen back in with the camera upside down. That way the shim will stay in place during reassembly.

Last edited by chromo; 01-02-2012 at 07:00 AM.
01-02-2012, 07:33 AM   #340
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Recently I was shooting in dim indoor light, and found that an f/3.5 lens was very dark in the VF, so dark I didn't feel I could focus properly. I can't compare to how this would have looked with the stock screen, but I was surprised at how dark it was. Note that this was really quite dim light, though. I just did a quick test with my DA 50-200, which is only f/5.6 at the 200mm end. It's workable even in a moderately lit indoor room.

Shooting in dim light with slow lenses is not something I expect to do much of so I'm not really concerned. I have found the S-type screen to be an immense improvement when shooting at wide apertures, and have no intention of switching back.
01-02-2012, 09:58 AM - 2 Likes   #341
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For fast lenses in good light this screen is much better than the stock. For slow lenses in low light, it is darker although the way it darkens is different than the stock screen. The stock screen is gets very grainy, this one gets uniformly darker.

For my purposes, mostly shooting with a 300mm 2.8 sometimes with a tc, it is a great improvement. If I put my 5.4 300 zoom on, it is slightly better than the stock screen, but slightly darker. The details are clearer even though it is darker.

As for low light, I was out late afternoon walking the dogs, flushed a grouse. The days are short here and it was getting dark. The bird flew into some evergreens and was barely visible by eye. I took some shots and was able to see enough of the white markings to focus, barely. The shots were very dark and I was able to get some detail out of them PP, nothing to show off though. But they were in focus. This with my 2.8. The stock screen would not have given me enough detail to get close to focus.

Buy this to solve the problem that it is designed for; being able to see the DOF of a fast lens. Other situations, low light, slower lenses etc. it is either marginally better or marginally worse than the stock screen. I wouldn't suggest buying it if you don't have the DOF problem to solve. But if you do, you most likely won't have to swap it out for other uses.
01-02-2012, 10:15 AM   #342
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Or buy it if you're using m42 and M lenses daily... It will save you a lot of headaches...
01-02-2012, 03:33 PM   #343
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Sounds like it might be a great thing if you could fit have both screens in side the camera and flick a switch to select the one you want.

I might stick to the original for now.
01-02-2012, 07:10 PM   #344
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I just received my Focusing screen and have been trying to fit it for at least 30 minutes. I can't get the screen to lock up in place. Has anyone else had this problem? Is there something other than the screen that's to be removed?

I went to the FS website and the instructions seem simple enough even though the English is poor.

Cheers & Help!!!
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01-02-2012, 07:44 PM   #345
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Had the same problem.

I had to remove the stock metal shim and replace it with the thickest plastic one from the kit and it clicked into place without a problem. Add or remove shims as required once you test focus.

I think the trick is not to align how it sits on the near edge of the frame but have it sit tight to the back and centered. It will tend to angle up from the frame.
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