Topic: Pentax program A, Super A or Super Program focus screen

All the information on the web suggests that the focus screen cannot be replaced on these cameras without doing a major dismantling job ...... not true !

For some strange reason every one of these cameras that I find has a really mucky focus screen. The latest Super A that I have just got was no exception, it looked as though someone had smeared the sticky foam of the mirror buffer on it and then tried to clean it off with solvent and wire wool so I had to investigate further, and it's quite simple.

Before you attack the camera, find a nice distant object that is easy to focus on (almost any lens will do). Focus as accurately as you can and then fix the lens focus ring with a piece of adhesive tape making sure that the ring doesn't turn remove the lens from the camera.

Inside the camera lens mount remove the 2 screws arrowed in the picture below this releases a hinged sprung frame, hold the frame up while removing the screws otherwise the last screw tend to fly off into neverland.

Let the frame drop down carefully and the the screen will now be loose and can be lifted out. You will see that the screen is fixed in a metal frame and has 3 adjusting screws, do not move these screws at this stage. If you only need to clean the screen then use ordinary liquid detergent in warm water, do not rub or scrub it, leave it on a cloth or tissue to dry on it's own. After that just put it back in.
Refit the lens and check that you have the screen in the correct position, point the camera at the same distant object and it should be in focus

If however you need to replace it then you will need a new screen and may be lucky enough to find another similar screen from the same type of camera. However apart from the metal frame the screen in these cameras is identical to those used in the Pentax ME super and they are pretty easy to find.

To replace the screen with an ME super type you will need to remove the old one from the metal frame, simply run a sharp knife or scalpel around the glue and the screen can be pushed out, make sure you don't bend the frame.

Clean out all the old glue and place the new screen into the frame with the Fresnal side (the side with the rings on) downwards. Using a dressmaking pin apply a small amount of glue around the edge between the screen and the frame. You need to choose the glue carefully because you need one that doesnt run and is not stringy. I used a glue that was made for fixing wood block flooring !
Definitely do not use Superglue or Crazy glue they will attack the plastic of the screen.  If in doubt about the glue you can test it on the old screen.

Once the glue is dry refit the screen/frame to the camera and check the focus with the lens on the same object as before. It will probably be wrong. If it is then using a long fine screwdriver you can adjust the height of the screen using the 3 screws without removing it from the camera. If you turn each screw an equal amount each time then you will retain the parallel alignment of the screen. You will probably only need about half a turn on each screw from the original position to get the focus back in the right position.

That's it, all done .... it took me longer to write it up that it did to replace the screen.

Statistically, 6 out of 7 dwarves are not Happy.

Re: Pentax program A, Super A or Super Program focus screen

Thanks for this tip. I just checked my Pentaxes -- they're all Spotmatics and K-series. None of them have the two screws you show, but I still like to know about this sort of thing for future reference.

One tip I picked up from a camera tech years ago that might come in handy with your procedure: to clean a focusing screen, what he did was drop the screen into a fim canister and fill it with warm, mildly soapy water. Replace the cap and shake for a while. Lather, rinse, repeat as many times as is required.

I have run across cameras with screens that were smeared with decayed mirror foam and what I did was use fingernail polish remover (aka acetone) on a q-tip to clean off the residue. This works very well when the smear is on the exterior of the screen, which is usually the case. If it's on the interior, then obviously the screen must be removed.

Last edited by cooltouch (2015-03-12 14:40:57)