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Edonar 105 f2.8 - Sometimes there are surprises
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PostPosted: Wed Feb 21, 2018 9:01 pm    Post subject: Edonar 105 f2.8 - Sometimes there are surprises Reply with quote

I posted here

http://forum.mflenses.com/whats-the-latest-lens-you-added-to-your-collection-t73516,start,1350.html#1506921

about the subject lens. The seller described the lens as being in "great" condition and listed it as used.

Upon arrival the lens was not functioning. I do not believe the seller realized there was a serious problem. I ended up getting the lens completely for free. However:

The aperture of the lens was not functioning at all. A couple of the leaves had popped their slots and, I later discovered, become bent. The front portion of the lens, the front lens group, was in very good condition. But the entire rear of the lens was covered in gooky, sticky, dried out oil. This is why the aperture failed

I am not at all an experienced hand when it comes to lens repair. My skills in the lens repair art are those of a student. But the lens was wholly unusable as it was. Since I owned it for free I decided to tackle the aperture problem.

Just extracting the aperture was a challenge, a "learn by doing" sort of thing. Everything was covered in half-dried goo. The lens came from California where there is no shortage of warm weather. I have to assume it was exposed repeatedly to too high temperatures, those incidents having all but ruined the lens.

With the aperture out and with the leaves spread open, the bent aperture leaves became apparent and stood out vividly. I tried my best to restore the original flatness of the leaves, but really it was pretty hopeless. I wiped away the oil and goo one leaf at a time, fifteen in all, using toilet tissue. Upon reassembly, much to my surprise, the aperture seemed to work OK.

At this point the lens remains disassembled. I'm not really certain whether I will be able to reconstruct it or not. The largest issue now is the weather:

It is winter where I live, and cold outdoors. This lens almost literally cries out for thorough cleaning with a solvent, naphtha being the one of choice. I cannot work on the lens outdoors. I cannot work on the lens indoors, at my lens bench, without opening all the windows in the room. I do VERY poorly if I try to use solvent in a closed room. This is because of the fumes. My body does not handle solvent fumes at all well. For me, fresh air is a must when using solvent.

So things are mostly on hold at this point awaiting warmer weather. One thing I did notice about this lens:

Obviously the helical is apart, its old lubricant having brought about the lens's demise. I will be re-lubing the helical with Helimax-XP after it is properly cleaned with solvent. I notice, though, that the helical seems able to rejoin at any rotational position, without need to find the "right" slot. The only other lens I've had apart that exhibits this quality is an Angenieux lens. It is interesting to contemplate that this Edonar might be machined to the high standards of an Angenieux lens. There is never a dull moment in this life.