How To Clean A Mamiya C220 Ground Glass

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IanBarber

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Dec 3, 2013
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Doncaster Yorkshire UK
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grahamp said:
The C220 screens are often shimmed - they are not intended to be swapped, so this makes sense. Be gentle, and take reference pictures. If you get the screen misplaced it will throw off your focus.
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Ah, Thanks Graham. In that case I won't disturb it and just put up with the marks I can see on it through the magnifier.
 

shutterfinger

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Feb 25, 2013
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San Jose, Ca.
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Remove the hood.
Remove the focus frame retainer.
Lift the focus screen straight up. Any shims are between the focus screen and camera frame. The shims are likely brass. Sinar used paper shims on their ground glass which would deteriorate with age causing a loose ground glass and focus errors.
If you are not experiencing a loose focus screen and focus errors the shims, if needed, are likely brass.
Lifting the focus screen up carefully will reveal the shims and their positions.
 

flavio81

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Lima, Peru
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IanBarber said:
Ah, Thanks Graham. In that case I won't disturb it and just put up with the marks I can see on it through the magnifier.
Click to expand...

My advice is, even if you keep the shims, do confirm for correct focus using a ground glass on the film plane. I had one C220 and one Mamiyaflex C2 where there were some shims yet the focus was incorrect. This causes serious lack of sharpness and then people start blaming the lenses.

Of course do this test with a known good lens.
 
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