View Full Version : Accessories Focus screen DIY

10-17-2007, 02:20 AM
Some time ago I found a site with a photo story of building the focusing screen (split microprism from an old camera, cutting and adapting it to an oly e1).<o:p></o:p>
Now I was no table to find it again.<o:p></o:p>
Have you any ideas (web site address :)<o:p></o:p>
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10-18-2007, 01:50 PM
Well, that could be my post at dpreview (http://forums.dpreview.com/forums/read.asp?forum=1022&message=13451982) back in 2005. However, the images are lost from that post so you will have to read the text and use your imagination. I had a quick look at my harddrive but couldn't find the shots right away. If I find them, I'll post them here again.

Cheers, Jens.

10-18-2007, 05:03 PM
Thanks. Just post a site address when you find those photos.<o:p></o:p>
Thanks again for your help.<o:p></o:p>
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12-16-2007, 04:12 PM
OK, I stumbled over the pictures today so here comes, on demand, an old favourite originally posted on dpr:

DIY any kind of focusing screen for the E-1:

I have modded two different OM-screens, one 1-1 for general purpose and one 1-7 for super telephoto, to fit my E-1 and improve manual focusing.
The manual focusing capabilities are truly improved down to f/5.6 with the FS 1-1 and with the FS 1-7, the super bright microprism allow me to focus my 1000mm f/10 mirror tele (real mm:s) but DOF won't be visible and focusing must be done with the microprism. The OM-FS are also very good for macro in combination with a Varimagni finder. (I modded one of those for the OM as well: http://www.myfourthirds.com/document.php?id=9104 .)
However, the operation has a price and that is that the metering will vary a lot with different focal lengths due to the Fresnel lens pattern moulded into the focusing screens. Therefore, I have mostly used it with primes so that I can make a permanent exposure compensation depending on the lens.
For example if I use the DZ 14-54 with the FS 1-1, it under expose one stop at 14 mm and over-expose one stop at 54 mm (center weigthed). With the FS 1-7, it will expose normally at one end of the zoom range but over expose by 4 stops at the other end.
It is quite easy to do the modification and in case someone want to make it a try, here is how I did:

First make sure the OM screen is clean and then cover it with an office tape that doesn't leave residues on the surface.


"Scotch Magic" used to be the best but they recently changed the formula so that it can actually leave tiny pieces of residual glue. You must test this first, for example on the edge of your screen which will not be used anyway. The tape will protect the surfaces of the screen while working on it. In any case, don't press hard on it to avoid getting ghlue into the microprism grooves.
Second, centered on the OM FS, mark the size of the E-1 FS (18.8 mm x 14.8 mm) on the scotch with a fine felt pen. Also mark the tweezer tab location (note that the matte/microprism side is to be located upwards in the camera).

Now cut off the surplus, leaving a few 1/10:s mm on each side,with a fine hacksaw.


Use a file to trim to the final size and shape the tweezer tab.


Third, make sure that no raw bearded edges are left before removing the scotch on the under side (polished side).

Be very careful to check that no residual adhesive from the scotch is left. If so, use a new fresh piece of scotch formed as a ring around your finger tip with the sticky side outwards to carefully lift it of by gently touching the contaminated part with the fresh tape.

Fourth, as the OM FS is only 1.2 mm thick but the E-1 FS must be 1.5 mm, I placed two very narrow strips of tape (0.5 mm wide and 0.3 mm thick) on the under side (without Fresnel pattern) along each short edge. This will ensure that the cradle for the FS in the E-1 lifts the Fresnel side up into correct position for seing the image in focus at the same time as it is in focus on the focal plane.

Fifth, remove the scotch from the upper side and sheck with a loupe that there is no residue.

Finally, install the screen in the camera and go out shooting manually with true OM-feel!

Cheers, Jens.