K20D focus screen shims

Where can I get these in the UK? Do they come in a set of several thicknesses?

I'm currently using a couple of strips of post-it note which seem to work okay, but I'd prefer to have the real thing and not worry about the post-its detaching or spontaneously combusting or something.

Thanks!

Pentax and Kateye screens do not require any shims at all in the K20D.

If using some funny other screen that requires a shim, it should be supplied by the manufacturer of the screen.

Hi Tim, Pete

That has not been my experience.

Rachel at Katz Eye sent me this information when I installed my screen in my k20d:

My camera had a 0.30mm installed, I found the 0.20mm did a better job in the focus tests. Now my manual focus and autofocus are exactly at the same point.

Dick

The shims must be option to correct a certain obscure problem then.

Normally no shims are supplied with or for the K20D by Pentax or Kateye, nor for the K10D or K-7.

No shims came with my K10D or K20D. I've recently ordered a K-7 too and am not expecting that to come with a shim either.

There is no mention of "shim" in the Kateye installation guide for the K20D, though there is for the K100D and K200D, for examples.

rlebleu, can you confirm that you have a K20D rather than a K200D. Thanks.

My k20d already had a shim behind the original focus screen (but my k100d did not).

After putting in a Chinese split focus screen into the k20d and running some tests I established there was a backfocus problem, so I needed a thinner shim than the pre-installed one. So I removed the k20d shim and used post-it notes instead, which is much better but still not quite perfect - so I'd like the real thing.

The k100d worked fine without any shims at all (same type of focus screen from same ebay seller, and taken from the same model Minolta MF camera I believe, just ground down to a different size).

Thanks for the info about Pentax dealers and the part numbers rlebleu, I will enquire at SRS.

Yes indeed. But the shim does not drop out with the focus screen. You have to lift a little 'tab' (don't know the correct term) to allow it to fall out. It sits between the focus screen and the pentaprism. I used a wooden toothpick to avoid scratching the pentaprism.

My Katz Eye was originally installed in a K10d, and no shim adjustment was necessary. But when I moved the screen to my k20d, and adjusting the auto focus to correct for a little front focus on my DA16-45, I noticed that the Katz Eye showed slightly out of focus after auto focusing. Since the focus tests clearly showed the auto focus was bang on, it was obvious that the focus screen had to be off.

So I ran focus tests with a 50mm 1.7 manual focus lens with a target and confirmed that using the Katz Eye prism to focus, my M50 was indeed front focusing.

I emailed Katz Eye, and they confirmed the problem. After changing the shim, and testing again, I was able to remove the manual front focus problem.

Now manual focus, and auto focus match perfectly using the center prism focus of the Katz Eye.

Dick