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Haig Hovaness
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, December 09, 2004 - 07:33 am: | 
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Does anyone have a clever method for removing dirt from the crevices in the wedges of an SLR split-image focus screen? Would an ultrasonic cleaner work? I am very reluctant to apply any implement to the soft optical plastic. |
Winfried
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, December 09, 2004 - 08:02 am: |
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I think an ultrasonic cleaner is the ONLY thing that works. I had several focus screen (without split image, but with microprism) cleaned by the optician next corner for a few dimes for their coffee budget. They all came out of the bath crystal clear.
The simple and cheap ultrasonic cleaners sold for hobbyists (claiming to be able to clean jewelry, eye glasses etc) don't seem to work very well. I once bought one and returned it next day. The water in the tray (plus a few drops of dish cleaner) seemed to remove more of the dirt than the ultrasonic procedure.
You are absolutely correct being very reluctant to rub with anything on the plastic. Whatever you will use, it will leave traces in the very small concentric grooves of the fresnel structure of most screens. Only DIY thing that worked more or less is immersing the screen in a strong solution of dish cleaner and drying it on a dust free place. You should keep it more or less vertical, with the lower edge resting on two points only to allow the solution to flow down without leaving any stains. |
Haig Hovaness
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, December 09, 2004 - 08:59 am: |
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If I understand you correctly, you are recommending a high-power ultrasonic cleaner for focus screen cleaning. I'm going to see what I can find on eBay. I've used water and detergent, but it doesn't remove all the dirt from the tiny crevices. The dirt on the screen is often very sticky, especially in a camera with deteriorated mirror bumper foam.
I'll let you know if I find an affordable ultrasonic cleaner that does the job. |
Jackson
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, December 15, 2004 - 05:55 pm: |
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I've cleaned several Nikon focus screens successfully by rubbing the fresnel surface with a wet bar of Irish Spring soap. I then use my fingers to rub the screen under running warm water until the soap is gone, and finally pat dry with a lint-free cloth. Ivory works too, but the screen doesn't smell as good.  |
