Lens Tech Genesis

LENS TECH GENESIS
"I fix lenses"

How all this got started...

The Purchase
I'd purchased a Canon AE-1 Program new in 1982. The salesman talked me into buying a 28-85mm Kiron zoom with it, rather than the stock Canon lens. I'm glad he did. The Kiron performed flawlessly for years, and was a joy to use. The whole outfit was $929, of which $349 was the lens.

The Diagnosis
Ten years later, my pictures had become overexposed and out-of-focus. I had another lens, and its shots were fine. It had to be the lens. So, off to the local camera store, where the diagnosis was: "The aperture's wide open all the time." "We can send it away for you."	If you live in a small community, then you know that "away" is where everything is sent: cameras, watches, electronics, printers, power tools, appliances. Everything. Because "away" is where "they" have "trained technicians" and "experts" and "the proper equipment." So it was sent "away."

The Disease
On November 17, 1992, I paid $160.00 to retrieve my "repaired" lens from the camera shop. There was a note attached: "Oil on blades." And a question: did I ever have the lens near any oil? Alarm bells should have sounded right then. This "trained technician" was asking me where the oil had come from! My cost of ownership was now $509, but I was happy to have my Kiron back. After a couple of years, I began experiencing the same symptoms with the lens, so it was sent "away" again. This time it cost $154.48 on May 5, 1995, to get my baby back. And this time there was no note with it.	The focus was very stiff & lumpy, and the Infinity Focus overshot the barrel marking by a full half-inch. (See detail above.)

Another Relapse...
My cost of ownership was now $653.48, so, when the lens developed aperture problems a couple of years ago, I shelved the idea of having it "repaired" once again. I figured that there had to be a fundamental design deficiency in the lens, or it wasn't being repaired properly. I decided to have a look for myself. With a background in electronics & mechanics, I felt confident that I could disassemble the lens, given some information on its construction. So I set out to make myself knowledgeable. In addition to the aperture being stuck wide open with oil, the concentric inner barrels were awash in oil. And one of the barrels had been scored, where a "technician" had forced in a screw that was too long. (Maybe he'd lost the original.) It was obvious that the original unstable grease had not been cleaned out and replaced, and had simply recontaminated the diaphragm blades. Truly amateur.	An "expert" must have lost the original screws for this brass focus-guide, so "fabricated" 2 new ones with side-cutters. He didn't even square up the ends with a file. Of course, they completely chewed up the threads in the brass.

The Fix
The most common problem with lenses, particularly zooms, is oil contamination of the diaphragm blades. This oil comes from the breakdown of the "damping grease" used to lubricate the focus helicoid. Damping grease gives the focus and zoom that nice, smooth feel, without overshooting. But, it is a "time bomb." The grease separates with time, aggravated by heat, and the oil migrates to areas that were never meant to be oiled. Like the aperture. The only remedy is complete disassembly and cleaning of the lens, and relubrication with grease of proven stability. (I use a grease that has endured temperatures from -40°F to +110°F, and shows no sign of hardening or separating after 12 years.) All this takes time. A lot of time. I can't do it in under 4 hours, and I'm good at it.	The aperture is situated right in the middle of things. The aperture assembly from a Kiron 28-105mm F/3.2 is shown above.

The Time Bomb
Kino Precision Optics didn't know that the grease they used in their lenses would break down many years later. Perhaps, because these Kiron lenses are of such outstanding quality, the "pity factor" enters into their mystique. It's really a shame that such beautifully made optics carry this "bug."	A great many lenses from different manufacturers show this same problem. Some were made by Kiron. Vivitar is one example. If you have a Kiron lens, and have never had any trouble with it, Congratulations! If you have one that is sitting in the closet, because of this affliction, by all means have it repaired. Properly repaired, it should work forever.

Here's a Kiron 28-105mm F/3.2 disassembled - no plastic parts.

Competent Repair
Of the people out there servicing lenses, probably 80% are extremely competent, thorough technicians. It's just unfortunate that I happened to bump into the other 20%. And you might, too. There are no quick fixes, particularly for aperture problems, and I doubt that anyone could do a competent job for under $150. (I paid that for incompetent jobs!) If you can talk to the actual person who'll work on your lens, you're at an advantage over someone who has to send it "away." There's a plague of "Service Writers" in repair facilities nowadays, who ensure that you can't talk to the mechanic, even when 2 minutes of his time will save an hour of diagnostic time.	And the size and demeanor of the facility is no real measure of competence, either. A friend of mine, knowing nothing about plumbing, hired the largest plumbing contractor in the city, when building his house. He is the only person I know whose toilet flushed with hot water. Quite an experience, really! Or, my wristwatch, returned to me after servicing: with the hour hand directly over the hour, the minute hand was at 6 o'clock. What were they thinking! I've been inside lenses, where someone has partially disassembled them, to the point where they could spray contact cleaner at the aperture. This "fix" can last for a few hours up to years. In shopping for lens repair, ask a lot of questions.

Thanks for reading this. Feel free to contact me via e-mail: f35mru20458@shaw.ca

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Ralph Innes
Port Alberni, BC, Canada
e-mail: f35mru20458@shaw.ca