Split image focusing screen for a K3

I saw a comment on the Pentax Forum where a user mentioned the failure of a K3 to 'catch in focus' at 28mm when he had an old 28-135 zoom mounted. However, he said, there was no problem as he was using a NIKON split image focusing screen. My poor old eyes would love a split screen in the K3ii. (There is a Chinese one on E bay now and then but it has lousy reviews). Does anyone know about this purported Nikon focusing screen?

I have a Katzeye screen in my K200D and it's fantastic, much more accurate than the K-3's stock screen or even live view magnified with focus peaking. Alas, Katzeye are no more, so the options are cheap Chinese ones of questionable quality or cutting down a Nikon or Canon one, but that's certainly not something I'd attempt myself.

Like Jonathan I have a Katzeye in a K20, It is good and a straight replacement for the Pentax screen. But I'm sure I read that after the K20 body generation you had to use shims to position a new screen, so never bothered any more.

I have a Katzeye focussing screen in my K5 and it has made a world of difference when using manual focus lenses. I will miss it whenever I next purchase a camera body.

Not had to use any shims and focus accuracy does not seem to have been affected. Perhaps I should check the manual to make sure

link DPreview about fitting Katzeye to a K7

Thank you Barrie. The link has some useful information.

I've not noticed any focus inaccuracy but this may be due to me usually using f/2.8 or smaller with "fast" lenses, so the depth of field may mask any slight focus issue.

I'll check the size of the shim fitted to the camera. There is a post in the above link that suggests that different sizes were fitted by the factory and it may be that the one in my camera is correct for the Katzeye screen.

I had to use shims to get focus spot-on in the K200D with the Katzeye screen. I remember I had to wait around a month and pay about 30 quid for a full set of shims from one of the authorised repair places.

Shims are always a possibility regardless of the model. They make up for small differences from unavoidable manufacturing tolerances.

I loved the Katzeye screen in my K20D but have stuck with the stock screen in the K-3. Great shame Katzeye is no more, they did a great range of screens.

One of the things that is great about the LX/MX is the ease with which one can swap out the screen for one appropriate to the job at hand. I use a gridded screen with my shift lens.

K.

My MX has got a split screen. I was thinking of trying it in the K3. Any thoughts before I bust something?

I think it'll be too big and need to be cut down and you will likely need shims to get focus spot-on.