5D focusing screen shimming and viewfinder mod

[ludoo]

I recently swapped the focusing screen in my 5D for an original EE-S as I much prefer it for manual focusing, but after a few shots I noticed it was really hard to pinpoint focus. I examined my pictures, and noticed that all of them showed front-focusing.

After reading around, I saw mention of the shims used in the 5D to calibrate the viewfinder (here and here), and that when replacing screens you should recalibrate as their thickness is not consistent. So I started by removing the original shim, which changed the situation from severe front focusing to a minor backfocus, and am awaiting the original shims to properly calibrate it. Anybody else has done the same to their 5D?

And while I'm at it, I also thought about how to remove the superimposed focus indication placeholders, those damn small black squares that pollute the 5D viewfinder, and are really bothering me. It seems that -- while the lights are below the mirror -- the ugly squares are etched on a separate screen which sits on top of the focusing screen, as seen here (image source)



and depicted here in the parts manual, where you see from the bottom up the focusing screen holder, the focusing screen, the shim, and the superimposed image screen



So I ordered a replacement superimposed screen, and will try to cut out most of it only leaving a thin border, hoping it will enough to make the ugly swaures disappear leavign me with a bright, uncluttered viewfinder. Anybody else has tried, or thought about this?

Edit. I forgot to say that the local Canon Service lab guys are jokers: I called to order the shims, and they told me they cannot sell spare parts to anybody. I told them people regularly buy them in the US, and they replied they don't care. I then asked if they can calibrate the vf then, and they told me "we have never done it, but you don't need to anyway, just select the proper screen model in the menus on your camera". I laughed in their faces and hung up. And now I have to order parts from the UK. Canon is often praised for their high level of support, but I guess here they're adapting to the Italian way...

[poilu]

I was lucky with my 40D and my 5DII that was perfectly adjusted
thickness of Canon screen are certainly correct, it is the slr that is off
Canon just assume that user will use AF and don't care about adjusting them

[visualopsins]

Another thread re: Canon Focus Screen Adjustment Washers, see post #22 for nice graph showing effects of focal length, washer thickness on front/back focusing.