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Post by Rachel on Oct 9, 2012 14:36:35 GMT -5
I hardly dare watch any more of this
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mickeyobe
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Post by mickeyobe on Oct 9, 2012 19:59:34 GMT -5
Fear not, Rachel.
The good guys always win in the end.
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truls
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Post by truls on Oct 10, 2012 6:19:04 GMT -5
Now I need an expert opinion. I have cleaned the lens elements but a close up exmination shows some artifacts in the lens, what could it be? Is this due to age or maybe fungus? It looks like air bubbles, but don't know... It is non-cleanable.
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Stephen
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Post by Stephen on Oct 10, 2012 6:45:34 GMT -5
It is minute air bubbles, they are not important, and will not affect or degrade the image any more than before. Quite a lot for Zeiss glass mind you, it may have been made in early wartime, and standards may have slipped a bit. The cleaning is for the surfaces, and will improve the performance, internal flaws should be minimal against the focused image. Make sure the final dusting etc is done carefully, just before re-assembly, carefully clean the trays and bench, lay a sheet of clean paper over the work area, vacuum the area, use latex gloves, and cover the forearms to minimise dust and detritus getting on the surfaces as you work.
When together again, use with deep hood, and a minimum of a yellow filter, it will help restricting the light wavelength being focused by the lens.
Before assembly see if any internal surfaces can be re painted with matt black to minimise reflections, make sure the paint is really dry before the assembly work.
I assume you noted the way the iris is assembled, try just one blade to observe the operation on the two pivots, and then work around the lot, interweaving the blades. It may help to use a small piece of Blu tack rubber "adhesive" to lay under the blades to prevent them moving , it will peel off afterwards, when all are in place.
Parts can be "wipe lubricated", oil the parts, then wipe off with a tissue, it leaves just enough oil film to lube the parts and prevent corrosion.
Watch makers silicon based oils are best, but sewing machine fine grade oil will do. A new type is "nano oil" from the States, which is used for many precision oiling jobs, like watches and clocks, and Model Railway items. It claims to last without evaporating or thickening.
Stephen.
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Stephen
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Post by Stephen on Oct 10, 2012 7:03:15 GMT -5
For reference, no commercial connection, Nano Oil is available widely in the Gun Trade as well as Clockmaking etc., A web search will show the makers site and suppliers, it has been on Ebay as well. Small packs are made, it is expensive, but I have found it works very well, as very small amounts are used. Be warned it is a patented product, appears to make big claims, and it is up to you whether it is believed!!!
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Post by herron on Oct 10, 2012 13:34:21 GMT -5
Now I need an expert opinion. I have cleaned the lens elements but a close up exmination shows some artifacts in the lens, what could it be? Is this due to age or maybe fungus? It looks like air bubbles, but don't know... It is non-cleanable. It does not look like fungus. More like dust. Are you certain there's no way to get the lens out of that housing? Are those screws that can be seen?
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Stephen
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Post by Stephen on Oct 10, 2012 14:56:29 GMT -5
There should be no need to release the lens, it is an un-cemented solid glass, after a clean with peroxide and ammonia it would kill any fungus, but it looks more like inclusions in the glass. Do try the cleaning several times, it can take time to wash away all marks on the surfaces.
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truls
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Post by truls on Oct 11, 2012 6:55:49 GMT -5
I will do the cleaning several times, and apply the advice from Stephen, thanks!!
It looks like dust but it is not, the picture is a close up which shows what the eye not is able to see unless enlarged.
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truls
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Post by truls on Oct 11, 2012 17:19:20 GMT -5
The assembling of Tenax I has begun. All lens elements looks clean and shiny. This has been a great experience for me. Thanks to all comments and advice. I will take some new shots tomorrow. Here is the aperture assembly, it also worked afterwards
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Post by Rachel on Oct 12, 2012 3:11:47 GMT -5
Phew, truls, that's a relief
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truls
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Post by truls on Oct 14, 2012 8:03:57 GMT -5
The new Tenax I test after cleaning was not promising, something must have been wrong during reassembly. There is a loss of sharpness. Could the middle lens element have been reversed mounted or misaligned? The church, bad lightning conditions: I will investigate this, doing a new assembly. Fomapan ISO400 1/100 @f.5.6 Normal development in fomadon R09 No lens hood or filter
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Stephen
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Post by Stephen on Oct 14, 2012 11:07:41 GMT -5
On the basis of the shot via the net, the second test looks sharper, and more contrasty, (the roof tiles show better).......but to check, verify first at full open, that the infinity setting is correct, and not past infinity (500+ metres target). Use ground glass in film plane, with a powerful lens to view it.
Collimation,(centering of lens), should not be too critical, unless the middle lens can move sideways a lot.
Front element was not removed from mounting ring, middle element had ring?, and rear element was in ring mount, so ought not to be far out, yes, check middle was not reversed etc. The final focus tweak should be to the front element, but I do not know if you released it. Most likely just needs another go at assembly, till it is right. Stephen.
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