OK....I am going to cut a screen to use in the film slot of my M's to calibrate the focus of various lenses. My question is how large to cut the screen? Obviously the length of the picture area is 36 mm but that's not an issue because the M cutout is more than 36 mm, that is if you place the glass below the rails or even on top. the height is supposed to be 24mm although the width of film with perforations is 35.3mm or so.
So where does the fresnesl screen go....on top of the rails or inbetween? The screen is obviously thicker than film. furthermore , after check my m4 and M5 there are different sized insets for the rails. Just wondering how to make it fit. Seems like it should be easy to cut a piece of glass or plastic for a focus screen and just tape it on the rails somehow.
Also, would it be helpful if there was a central high performance focusing prism in the center?
So where does the fresnesl screen go....on top of the rails or inbetween? The screen is obviously thicker than film. furthermore , after check my m4 and M5 there are different sized insets for the rails. Just wondering how to make it fit. Seems like it should be easy to cut a piece of glass or plastic for a focus screen and just tape it on the rails somehow.
Also, would it be helpful if there was a central high performance focusing prism in the center?