help: cleaning Vaskar rear element on Bessa I

lynnb

lynnb

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Today I bought a Bessa I for $20 at a camera fair. The rear element of the Vaskar lens is mouldy - at least I think it's mould, as I don't know the difference between mould and haze - see pictures. Figuring $20 is not too much to lose, I've removed the lens/shutter assembly and am now trying to figure out how to remove the rear element to clean it.

From what's I've gleaned through searches, the element will screw out if it's gripped firmly with rubber or some sort of grip that won't damage the threads on the outer barrel. It seems stuck.

Do I try to unscrew the black retaining ring separately from the outer threaded barrel, or does both barrel and retaining ring unscrew as one unit? i.e. do I try to get a grip just on the black retaining ring in the photo, or do I try to unscrew the threaded barrel?

Finger pressure alone, using a thin rubber mat to grip, isn't sufficient to loosen it.

Appreciate any advice from knowledgeable people!

Lynn

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Well, Lynn, I've only dealt with the pop up viewfinder 6x9 Bessas (which, interestingly, pre-date the "Bessa 1"). Not having the benefit of perusing yours in person, from the photos, I must say my first instinct would be to place some protective tape over the centre of the glass, place the whole unit rear down on some rubber (eg. an old bicycle inner tube) and applying gentle pressure, see if you can gently unscrew the black ring. I'd seriously doubt the optics all remove from the front on a Voigtlander of this vintage, no other classic one I have seen does this, and the rear glass is unlikely to be able to be removed unless the black ring comes off first, so I would try that for starters. It will be a normal right hand thread, so anti clockwise to remove...
Let us know how you get on.
Best,
Brett
 
Thanks Brett. I found a description and photos for removing the front and middle elements, but those appear to be in good enough condition to leave untouched. I'm too nervous to risk damaging the shutter and aperture mechanism by going through the front. Photo #1 in that thread shows the rear of the lens (same as my pictures above) and photo #5 shows that the rear lens element has been removed.

There's an even better description here, with pictures, which seems to confirm the black ring unscrews to release the rear element. He just doesn't say how he did it.

I'll find some inner tube and have a go using your suggestion tomorrow morning (it's very late here).

Cheers,
 
Got it! I used a rubber bath mat sitting on carpet, and now the rear element is out. Fantastic.

Now to see if I can clean it. First will try some lens cleaning fluid and a micro fibre cloth...
 
... my 1933 Bessa came out after removing the black retaining ring like this ... probably not really useful

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Went through three of them. One with Vaskar, no difference.
The rear one was always less difficult to unscrew, comparing to front one.
It is not the ring. It is lens in the ring. You need to use some rubber to unscrew it. No tools, just something soft to increase tension.
 
thanks guys. I have it out - now how to clean it? The pictures below show the fungus/haze/whatever-it-is. Lens cleaner and methylated spirits (alcohol) don't make any difference. Any suggestions? Gently polishing with toothpaste?

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incidentally the front and middle elements are in great condition. It's just this small rear element that's in a sad state. If I can successfully clean it, I'll be very happy!
 
I washed mine in lighter-fluid .. took off the gunge but there were one or two places where the glass was etched
 
hmmm.. I could buy some lighter fluid and try it, but before I do, does anyone else have suggestions for getting the grunge off? I just did a quick search and one suggestion was hydrogen peroxide solution. Has anyone tried that?

All advice gratefully received!
 
Try soaking it in Windex for a day. If that does not work, then try the hydrogen peroxide:ammonia solution.
If that does not work ... then you can try polishing with toothpaste as a last resort.

I've had a couple of lens elements that I could never get clear with any of the suggestions above and they looked like what you have.
 
thanks - soaking in Windex now… if I'm near my optometrist tomorrow I might ask him for suggestions as well...
 
... the technician I used once suggested using cold-cream, but I've not tried it

PS I washed the diaphragm, shutter and slow-speed escarpment with lighter-fluid too ... once the old lubricant was gone the whole lot worked perfectly again. I put a film through it each year now and it's still going
 
I have a rear element on a Spirotone lens in similar shape. reading online on how to clean it I read that on many glass lenses they cement two elements together & the haze, mold, sometimes it's the cement used itself that causes the problem because of seperation. Bottom line is the crud might be inside the lens between the two elements & that is why you can't get it clean. Good luck with yours Lynn.
 
Hands down the best thing I've used to remove fungus is moisturizing hand cream. Apply with cotton swab, let sit for 10 minutes or so, then remove with additional swabs. Afterwards clean lens with usual products to remove residue. If anything will remove fungus, that's it.
 
That Vaskar should be a 3 element/3 group setup, so there would be no cemented doublet in it.
I think this is more of a case of haze than fungus ... which in my encounters, it the worst of the two.
 
dxq.canada said:
That Vaskar should be a 3 element/3 group setup, so there would be no cemented doublet in it.
I think this is more of a case of haze than fungus ... which in my encounters, it the worst of the two.
Click to expand...

My rear element has haze & I've done everything I know of to try & get it off. I really don't think mine is a douplet either but agree haze is a PITA to get off. if Lynn suceeds then please share on here because I'd like to get mine cleaned up.
 
I've had some success (though not as complete as with moisturizer and fungus) removing haze with silver polish (I've used Flitz). Toothpaste would probably provide similar results. Little to lose, really.
 
I'll have a chat with my optical dispenser today and see if he has any ideas. I remember reading about some people having success with cold cream, so if the optical dispenser doesn't have any better ideas I'll try that next. I'm assuming cold cream acts as a very fine, very mildly abrasive polishing paste.
 
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