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06-25-2015, 02:21 PM   #1
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internal viewfinder cleaning/repair?

So I just got a Sigma 28mm f/2.8 and went out into my front yard to check it out when in the process I noticed that there were some specks in the viewfinder. I figure this is from the black foam lining that's deteriorating in the internal part of the camera. I've tried using a cloth lightly on it with very simple lens cleaner/alcohol as well as qtips. I thought I had gotten it all off, but I still see two light smudges in the viewfinder, and can't coax them out. Any ideas? Am I going to have to take this to a pro to get it cleaned properly? Perhaps I'm being ocd? I was going to take it to get it checked out throroughly anyways after the original purchase of it, but I'm refurbishing most of what I can myself. I appreciate any help.

Thanks for reading.


In the image below the two specks are in the top middle of the internal viewfinder. I tried to get them in focus and visible as best as I could.

06-25-2015, 03:59 PM   #2
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Ok, I am assuming that you are asking about your recently acquired ME Super film camera. If so, here are a few bullet points:
  • The junk you saw on the focus screen is likely due to degraded mirror bumper foam
  • Avoid cycling the shutter until you replace the mirror bumper. As you discovered, the mirror will fling the chunks of goo all over the inside of the mirror box with potential to foul the focus screen, mirror, shutter, lens rear element and so on.
  • Avoid touching the focus screen. It is very fragile and easy to scratch. It can be cleaned, but doing so requires that it be removed from the camera. Do no use solvents on the screen.
  • Avoid touching the mirror. It also is very fragile and easy to scratch.
  • If you pay for a CLA (Clean, Lube, and Adjust), the technician will clean your sullied screen as part of that service
  • If the mirror bumper is bad, chances are that the light seals are also degraded
  • Replacement of the mirror bumper and light seal foams is also part of the CLA
  • You can replace the seals and mirror bumper yourself. I recommend the excellent kits from Jon Goodman. Along with the kit, you will need lighter fluid (Ronsonol), soft cloths, good eyesight, a stead hand and a pair of forceps or tweezers. Doing the seal and bumper replacement is not likely to reduce the price of the CLA. I would just get the CLA.
  • Again, cleaning the screen is not something your can do for yourself. It requires partial disassembly of the camera (remove top cover, connection ribbons, pentaprism, and the screen itself) and appropriate tools.
I hope this helps.

06-26-2015, 11:08 AM   #3
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QuoteOriginally posted by dcshooter Quote
The only exception would be in certin older design SLRs with fixed focusing screens that require disassembly of the top of the camera to remove the screen.
That would include all of the film SLRs on my shelf as well as the OP's ME Super. Once the screen is out, the dish soap process your describe works well and is the method used by my local tech. As for the and I may know the meaning of the words "light pressure", but based on the number of cameras with scratched mirrors I have seen and the difficulty sourcing replacements* ...

Depending on the availability of funds and the OP's desire to learn the inside of the camera, it is sort of a toss-up with an ME Super. I would probably do the CLA myself, but then again, I have operated on many cameras over the years.


* My Pentax SV had serious scratches on both the mirror and focus screen when I bought it. Eric was able to replace the mirror with one from a parts camera, but did not have a good focus screen.

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