Lens repair for Canon EF 35-350mm f3.5-5.6L USM

[milljam1257]

I bought a used Canon EF 35-350mm f 3.5-5.6L. I started having intermittent lens to body communication errors. The Error has become more frequent. I have fairly confidently verified that the problem is the lens, not the camera, by using my other lenses without a problem. On inspection, I noticed visible wear on the lens contacts. 

I contacted Canon Technical Support about the possibility of repairing the contacts. They told me that it can be done but Canon no longer supports this lens.

It's a clunky old lens but It beats the heck out of anything else I have (or can afford) for image sharpness. 

Are there any other options for repairing this lens besides Canon?

[ebiggs1 · Accepted solution]

Call Midwest Camera Repair.

[kvbarkley]

You might try to find an old "parts only" lens on ebay. I would suspect most of the contact rings are interchangeable. You can look at a few of the LensRentals teardowns to be sure.

[ebiggs1 · Accepted solution]

Call Midwest Camera Repair.

[milljam1257]

Thank you. I got a cost estimate from them for repair. Worst part would/may be the 8-10 weeks backlog.

[wq9nsc]

Although I am generally not a fan of "magic mouse milk" solutions, in this case you may find that Deoxit gold in the pen applicator formula will restore functionality if it is just a contact issue.  Start with a careful cleaning with high concentrate isopropyl alcohol and a lens quality cloth to clean the contacts on the lens, do the same for the camera body while you are at it.

Allow the lens contacts to dry, then carefully apply the Deoxit contact conditioner to the lens contacts ONLY.  Alow them to dry, do a second treatment and again allow time for the carrier to evaporate and then try your lens to see if that restores functionality.

There are some conductive greases that are generally silver bearing and are useful for a lot of applications but NOT, repeat DEFINITELY NOT, for this purpose because they will also bridge the nonconductive gap between pads and will cause damage to the camera.  I use silver bearing grease for high power rotary contacts where there is no issue of shorts/leakage and it works wonderfully but too many times people try this product where it does not belong.

Rodger

[ebiggs1]

If the gold plating is worn off I doubt any cleaning or magic milk formula will make it reliable.

[cicopo]

I have the same lens and as I understand it parts are hard to find. Non working doner lenses thru Ebay seems to be about the only parts source. That's the primary reason I haven't sold mine. Knowing it could fail after selling it & just become junk to the buyer isn't my way of doing things. Odly enough it's seeing some use because every so often my 28-300 decides not to communicate with 1 of my camera bodies so I quickly swap to the 35-350.

[milljam1257]

Thanks. I may try this first.

[jrhoffman75 · Accepted solution]

USCAMERA dot com sells the parts manual, repair manual and a contact assembly for that lens is no other option works out for you.

[milljam1257]

Thanks. Found the part and diagram.