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11-18-2011, 03:55 AM   #1
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KatzEye on a K7, is shimming required?

Hi,

I've just installed a KatzEye on my K7, the installation was fairly easy, and the viewfinder image is clear. However, when I focus on something using the split prism, the resulting photo isn't in focus, in fact, it's quite a bit off, even when I stop down my lens to say 5.6, it's not right.

I'm using a Pentax A 50mm 1.7, when close focusing, I'd say it's front-focusing by about an inch, but at distance, say 30ft, it's way, way off.

Can I buy shims (I'd rather not buy from KatzEye, as I'm based in the UK, not US)?

Is it normal for it to be quite a bit off before shimming?

Thanks for any advice.

Moray

11-18-2011, 04:02 AM   #2
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One way focusing could be way off would be having the screen inserted the wrong way (the matte surface should go towards the prism) or omitting the stock shim. If these are in order then you'll probably need a thinner or thicker shim. (see: https://www.pentaxforums.com/forums/pentax-k-5-forum/164287-katz-eye-installe...ml#post1701889)
11-18-2011, 04:15 AM   #3
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I've just been emailing KatzEye as i want to get a screen for my K5. KatzEye don't sell the shims, They are classed as a Pentax repair part.
I emailled the main repair centre here in Australia quoting the shim part numbers that KatzEye gave me and currently there are none in stock over here.

I was quoted a price of $2.25 Aus per shim.

I found KatzEye very prompt in replying to my emails, by comparison I also emailled focusingscreens.com with a similar query about their screens and am yet to receive a reply.
11-18-2011, 04:25 AM   #4
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I had to put a new shim in my K7 when I went to a Katz-Eye.

IIRC, the stock shim is .4mm and I needed a .2mm shim.

11-18-2011, 04:55 AM   #5
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I think the stock shim may be the problem, there wasn't one. I bought the K7 used (from this forum incidentally), and there wasn't a shim in it when I replaced the stock focussing screen. The previous owner used a 3rd party screen, so I guess it must have gone missing then.

Will need to track down a shim in the UK i guess.

Cheers

Moray
11-18-2011, 05:29 AM   #6
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Hmm, turns out I was mistaken, the stock shim IS there, it just wasn't what I thought it was. I removed the shim, and now it's back focussing rather than front. I'm starting to think a good solution would be to just buy an AF lens, and it's not worth the hassle!

Cheers

Moray
11-18-2011, 05:51 AM   #7
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QuoteOriginally posted by themugen Quote
Hmm, turns out I was mistaken, the stock shim IS there, it just wasn't what I thought it was. I removed the shim, and now it's back focussing rather than front. I'm starting to think a good solution would be to just buy an AF lens, and it's not worth the hassle!

Cheers

Moray
hehe I know how you feel.

I've gone through this exact same process myself.
Truth is, almost every camera will require shimming in order to adjust a focusing screen. However... in defense of the screen I'd say that it's worth every ounce of work getting it done right.

Having said that, if you're stressed-out over it, I would highly recommend sending your camera in to Katzeye to get it professionally adjusted. The owner is not only highly skilled at doing this but is very professional also(cleaning mirror box etc). And so I've got nothing but high recommendations for that.

The other alternative is to order order the shims from Pentax(they're pretty cheap btw), roll-up your sleeves and adjust it yourself. Surprisingly enough, it's not as hard as it sounds like, though it does take a fair amount of time and patience to get right. However the results far outweigh the efforts.

PS. I've installed and adjusted at least a dozen focusing screens in my Pentax camera's over the years. And like you, I used to dread the idea of doing this at first. But now, I actually enjoy it

Hope this helps.
And if you have any questions, I'd me more than happy to share any of my own experience on this with you.

JohnB
11-18-2011, 08:20 AM   #8
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QuoteOriginally posted by JohnBee Quote
hehe I know how you feel.

I've gone through this exact same process myself.
Truth is, almost every camera will require shimming in order to adjust a focusing screen. However... in defense of the screen I'd say that it's worth every ounce of work getting it done right.

Having said that, if you're stressed-out over it, I would highly recommend sending your camera in to Katzeye to get it professionally adjusted. The owner is not only highly skilled at doing this but is very professional also(cleaning mirror box etc). And so I've got nothing but high recommendations for that.

The other alternative is to order order the shims from Pentax(they're pretty cheap btw), roll-up your sleeves and adjust it yourself. Surprisingly enough, it's not as hard as it sounds like, though it does take a fair amount of time and patience to get right. However the results far outweigh the efforts.

PS. I've installed and adjusted at least a dozen focusing screens in my Pentax camera's over the years. And like you, I used to dread the idea of doing this at first. But now, I actually enjoy it

Hope this helps.
And if you have any questions, I'd me more than happy to share any of my own experience on this with you.

JohnB
I'll second all this. I sent my K7 to Katzeye for installation a long time ago. If you're uncomfortable with doing the installation, it's probably worth it, though if you're in the UK I would imagine the shipping would be a killer. It's fairly high here in the states. However, since that time I have gotten over my anxiety about it and have changed screens myself a number of times. I now have a Canon s-type in my K5. The whole installation/shimming thing is really more tedious than difficult, and John is right that it is worth the effort. Btw, I believe, but I'm not totally sure, that my K7 also used a .2 shim with the Katzeye, so that would be my starting point if I were you. If it's not that one, it's probably something very close. My K5 needed a .15 for the Canon.

11-19-2011, 03:53 AM   #9
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Hi JohnBee and DogLover,

Thanks for the suggestions, I think a 0.2 sounds about right, if it's front focussing with the stock (0.4?) and back focussing with no shim at all, the somewhere in the middle makes sense.

I'd like to send to KatzEye, but as a UK resident, it's not really practical, so I think the best way would be to source a 0.2 shim in the UK, any ideas where I can get one from?

I've popped the screen in and out a couple of times, and I'm OK with doing it, the shim seems more fiddly, but i guess it's less fragile, so I don't really mind.

Cheers!

Moray
11-19-2011, 08:06 AM   #10
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QuoteOriginally posted by themugen Quote

I've popped the screen in and out a couple of times, and I'm OK with doing it, the shim seems more fiddly, but i guess it's less fragile, so I don't really mind.
The shim that you will be using is just as, if not more fragile than the screen. If you bend the shim, the screen won't sit flat in the bay and you will get wonky focusing that can easily be mistaken for lens decentering.
11-19-2011, 09:16 AM   #11
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I've never done this yet, just to be clear, but it sounds like a good idea in this thread, where someone used thin strips of the self adhesive part of Post It notes as shims. Might be worth a try, or something similar like tape. I've read about various kinds of tape being used too.

https://www.pentaxforums.com/forums/pentax-dslr-discussion/45309-shims-focus-...tml#post433349
11-19-2011, 10:37 AM   #12
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QuoteOriginally posted by Wheatfield Quote
The shim that you will be using is just as, if not more fragile than the screen. If you bend the shim, the screen won't sit flat in the bay and you will get wonky focusing that can easily be mistaken for lens decentering.
The shims do bend very easily, but in my experience they are very easy to press back to fairly flat, and then when you install the screen it is pressed against the shim and the surface behind it by the retainer clip with pressure, forcing it to be flat. If you're dealing with a fairly thick shim I could see where it might not flatten completely back out, but then a thicker shim would be harder to bend in the first place.
11-19-2011, 10:42 AM   #13
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QuoteOriginally posted by themugen Quote
I'd like to send to KatzEye, but as a UK resident, it's not really practical, so I think the best way would be to source a 0.2 shim in the UK, any ideas where I can get one from?
From what I understand, getting shims is kinda dicey right now outside the US, so I'm afraid I can't offer any advice there.

Tbh, my advice would be to sell your Katzeye and order a s-type from focusingscreens.com I find it to be a much superior screen and they will send you (plastic) shims with it, along with some installation tweezers.
11-19-2011, 11:06 AM   #14
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QuoteOriginally posted by DogLover Quote
From what I understand, getting shims is kinda dicey right now outside the US, so I'm afraid I can't offer any advice there.

Tbh, my advice would be to sell your Katzeye and order a s-type from focusingscreens.com I find it to be a much superior screen and they will send you (plastic) shims with it, along with some installation tweezers.
I've contacted the official Pentax service people in the UK, so I'll see if they have them. If not, then I may give up, I just want to take photos really, fiddling with cameras isn't really my thing.

Cheers

Moray
11-19-2011, 11:35 AM   #15
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It isn't too difficult to fabricate your own shims.

A single Post-it is very close to 0.08+mm thick, two are 0.17, three are 0.26+, etc. Typical business card stock is about 0.22mm. Plastic credit cards are about 0.7 - 0.75mm.

You can achieve the thickness you want more or less by inspection and experimentation. Compare what you have to work with to the existing shim and adjust as appropriate. Note that it isn't the exact dimensional thickness that's important -- it's the relative amount of change that occurs and that has to be done by trial and error to get best results unless you have a calibrated test apparatus.

I've found that layering cellophane tape to the desired thickness on a plastic surface (easy to peal it off) and cutting appropriately thin border strips for the screens with a razor or 'Exacto" knife works well to make custom shims. Self-stick cellophane cooking wrap (Saran-wrap?) provides very fine adjustment layers but is a real pain to work with.

Consider the effort a semi-permanent, custom upgrade that'll stay with the body, spend the time to make a precise adjustment, and enjoy the results.

Remember that the VF screen adjustment does not affect the AF calibration which can also serve as a source of comparison.

If the plane behind the object you focus on is sharp, you need a thicker shim. Ideally, the body design would always require some amount of intentional shimming to allow for correcting both front or rear focus. Otherwise, the cost of precision manufacturing would be exorbitant.

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