Mamiya 100mm f3.5 Mamiya Press lens needs cleaning?

[John Wiegerink]

I recently purchased a 100mm f3.5 Press lens for my Mamiya Super 23, and it has internal fungus. The seller is in Japan and says he will cover the cost of cleaning. I need to get an estimate for having the glass cleaned. Yes, I know it probably will never be totally cleaned out, but it should still be alright for use. Anyone know of a reasonable repair person to do the job. I'm deaf, so using the phone for contact is extremely hard, but email works just peachy. Thanks, JohnW

Oh, this is how it was described:
Beautiful condition. There is no scratches. There is no separation.All lenses are generally clean. However, there is some dust contamination due to age. We don't think it will affect the photography.

 

[awty]

Surprisingly fungus usually cleans away easily. Dont think I have ever had one that doesn't just wipe away. Haze is another story.
Any camera tech should be able to do the job, probably worth paying a little extra to service to shutter while he's at it.

 

[John Wiegerink]

Surprisingly fungus usually cleans away easily. Dont think I have ever had one that doesn't just wipe away. Haze is another story.
Any camera tech should be able to do the job, probably worth paying a little extra to service to shutter while he's at it.

I have sometimes been able to clean internal fungus if it hasn't been there for very long. External fungus, front or rear element, can etch right into the coating in a very short time. The only way to clean that is to polish off the coating and have it re-coated. Just not worth it on many lenses, since you can usually buy a replacement lens much cheaper.

 

[reddesert]

The 100/3.5 is a Tessar formula. It has a front airspaced doublet and a rear cemented doublet. The front and rear groups should simply unscrew from the shutter. That makes it easy to get access to several of the surfaces to clean them. If you have to get into the airspace in the middle of the front group it will be more involved, I have not done that. Damage to the inside of the cemented rear doublet would be more difficult to address, but fungus is usually on an air-facing surface not inside a cemented pair.

 

[John Wiegerink]

The 100/3.5 is a Tessar formula. It has a front airspaced doublet and a rear cemented doublet. The front and rear groups should simply unscrew from the shutter. That makes it easy to get access to several of the surfaces to clean them. If you have to get into the airspace in the middle of the front group it will be more involved, I have not done that. Damage to the inside of the cemented rear doublet would be more difficult to address, but fungus is usually on an air-facing surface not inside a cemented pair.

Yes, I'm sure I can tackle the cleaning. Don't know if it will come clean or not. It does seem that fungus just doesn't have enough oxygen to grow between cemented element. I have two Rollei TLR's with etched internal coatings and it sure doesn't seem to cause any problems with the images they take. Both were cleaned, but once the coating is eaten away it can't be cleaned back again. It seems to take much longer for fungus to etch into glass with no coating. Must be the lens coatings used taste mighty good to those tiny little fungi critters.

 

[John Wiegerink]

I disassembled the lens and cleaned the elements with H2O2 and NH3 (Hydrogen Peroxide and Ammonia). Most of the finer strands of fungus came out, but sorry to say that it had already etched into the coating in some spots. It's certainly better than it was. It should still be fine for photos, but it certainly ain't pretty.