Focusingscreen.com S type for Pentax

luisalegria · Expire: 2018-01-18

I have been trying for several years, ways to improve my ability of manual focus on my Pentax cameras.
I am too conservative for live view, and that doesn't work for the way I like to use SLR's anyway.
I am sure I am not the only obsolete object around, so for what its worth, I think I have found the best retro solution.

I have tried several split image screens. None were much better than the stock bright fresnel screen that came with my Pentax bodies.

They were just as inaccurate as the focus confirm, and not as accurate as focusing by eye even on the bright screen. The stock screen does not show much difference between in-focus and out-of-focus areas, making it difficult to use, but better than nothing. Also there was always a problem of shimming the new screens correctly to match the sensor back focus. This is not a bit easy and I have messed around a great deal with home-made shims.

So I thought about the pure groundglass screens on my old Exaktas, and for that matter on my old plate cameras. These are perfect for sorting out in-focus from out-of-focus, and show a nearly identical view as what will come out on film. I think there is only one focusing screen maker with something like this - a Taiwan outfit,

http://www.focusingscreen.com/

They offer the "S" type groundglass screen cut down from a Canon optional screen. Its available or all Pentax models and many Nikons it seems, but strangely not for Canon.

Its not cheap at $ 73, but ...

http://www.focusingscreen.com/product_info.php?cPath=25_132&products_id=1170

Its a night and day difference for optical focusing accuracy, at least for me. Not much need at all anymore for focus bracketing, accuracy of focus is at least as good as on a film SLR. And the kit is very complete, coming with a selection of different thickness shims to adjust back focus problems. It still isn't easy to do this adjustment, in particular putting the shims in properly is a very fiddly process, but once done its done for good it seems. I did the adjustment with my Biotar 75/1.5 (minimum DOF for precision) to get it absolutely right, and it has done the trick.

Its quite a revelation to hit focus right off with a 300/5.6.
Highly recommended.