Originally posted by DogLover My K-3 came from the factory with no shims at all (the first body I've had like that) and the new screen also did not require any.
This is a little difficult to reconcile with what Rachael Katz told me, with the procedure to replace the *factory* shim in a K-3. As I have said, she is very helpful. This is the reason that I like working with her. Here is her very recent email to me about this (July 1st, 2014):
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"The K3 does utilize a shim. The standard size is 0.35mm. It is unlikely to have been displaced though, as it is retained by a little metal spring tab arrangement.
There is no published procedure for changing the shim because it is not considered a user-serviceable item; but I will do my best to describe the process.
First, you should take some time to clean up the camera, particularly the mirror chamber and lens mount, and prepare your work area. The screen will be out for a few minutes, so anything you can do to minimize dust incursion should be done. Next, the screen must be removed and safely stored. It will be out for a few minutes, so it should be placed in its protective bag to keep it from gathering dust. You will also need a good strong light source, like a desk lamp or a head lamp, that can be aimed into the camera so you can see the necessary detail. The tools required are an ordinary household tweezers with a standard wide tip (not the pointy type) and a small probing tool, such as a straight blade jeweler's screwdriver.
Now, if you look up toward the pentaprism (looking through the lens opening, from bottom towards the flash), you will see the shim where the focusing screen was sitting. Take a few moments to note the orientation of the shim. Notice the two tabs at the rear of the camera that retain the back edge. As you are looking from this angle (bottom of the camera toward you, camera on its back), you will see to the right of center, the small metal 'hook' that keeps the shim from falling out. Using your probe, gently lift that hook toward the lens opening and the shim will be freed. While lifting the hook, tip the camera up until the shim falls free and lift the shim out with your tweezers.
To install the new shim, hold it with your tweezers by the front edge (long edge without the two protruding tabs). Place the two tabs in their matching slots at the rear of the camera and tip the camera so the shim falls against the hook. Lift the hook while tipping the camera so the shim falls into place and release the hook. The shim should now be installed - tip the camera to ensure it doesn't fall out and visually confirm the small hook is once again holding the front edge of the shim. Check and clean any dust as necessary, and re-install the focusing screen."
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