oil patch on 135mm f2

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Hi. I just got a 135mm f2 from Ebay. I am quite excited to get this legendary lens except that i found a little oily patch of about 5mm long an about 2mm wide (Average) oily trace on one edge of inner element. I am perplexed because I didn't notice it when I opened the package but in a matter few hours it was there. It's so obvious (that oily rainbow kind of reflection) that I wonder I could've not seen it if it was there when I opened it.

Anyway my question is (assuming that this is relatively new occurence) 1. whether how much it will affect the performance (diameter is 72mm) 2. whether I could trust a local repairman to clean it and mount it back properly or I should trust Canon repair centre. (Or could I do it if I have proper equipment?) - Does it require precision to mount elements properly on a barrell? 3. should I clean it right away or would it be equally easy to remove it later.

I found inner elements a bit dusty so it could benefit from a clean-up but i wonder whether I should do it now and whether dismantling a lens could affect its performance.

Thanks!!

-- pil joo (gjoo@po-box.mcgill.ca), March 07, 2001

Answers

I work for a repair shop, and you would be surprised how little that patch will affect your images. I would shoot it first. If your intents are aside from using the lens to make images, say, collecting, toss money at it until you're happy. O/W I would wait for a sticky diaphragm or dirty elements(resulting in a severe loss of contrast) or something else to happen and clean the patch at that time. Shoot and see.

-- Mike DeVoe (karma77@att.net), March 12, 2001.

It shows some strong oily rainbow flare against strong light source in the view finder. I'll try running a roll through. If I decide to clean, should I do it as soon as possible or can I wait? Thank you!

-- pil joo (gjoo@po-box.mcgill.ca), March 13, 2001.

I lost a 135/2.5 in salt water 14 years ago. It stopped working.

I called Canon, and they sent me new diagraph-blades to mount myself. They also told me to clean the diagraph with acetone after I touched them, before mounting them.

I made a special tool (A round plastic piece and imitated leather for friction) for removing the front ring. I had no screwdrivers so I used a file to sharpen bent knitting needles. After a while, I would get cramp in my hands because they were so hard to hold. The steel in the knitting needles where so soft, I had to file them often. But sometimes it was good to have a screwdriver less solid then the screws, because sometime the screws was set so hard, I would destroy the screws with a normal toll (I have done this later).

The real problem was to mount the focusing mechanism when everything was in the right place. Even after I done it ten times, I had difficulties to do it. It worked out OK, and I sold it some years later.

Good Luck

-- Řyvind Dahle (odahle@start.no), March 15, 2001.


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