replacing worn contacts on EF 300 f/4 IS

[todd_west]

There's some contact wear on the old 300 f/4 IS I picked up used a while back.

The lens has always been a little prone to losing contact with the camera and

rolling over to aperture 00 but lately it's become quite unreliable. All of my

other lenses are completely reliable with my body and the 300 can be gotten to

work if one doesn't mind spending about ten times as much time fiddling with

the lens as taking pictures. So I'm high confidence the issue is with the lens

contacts and not the body or lens electronics. There isn't a camera repair

shop local to me and, calling around to Canon and a few shops within a few

hundred miles, no one will provide an estimate without looking at the lens

first. So I'm in the unenviable position of needing to ship the lens multiple

places to get competitive quotes, which adds a lot of cost, time, and hassle.

 

Anybody have a feel for what a reasonable cost is for replacing the contacts on

an EF lens or for parts? I'm certainly not mechanically adverse, so pulling

the four screws on the back of the lens and dropping in new contacts is

something I'd be willing to try if it's not too involved and it's possible to

get parts.

 

Looking through the various repair threads back to about 2004 it seems Canon

often ends up being cheapest. Any sense if this is still the case? I called

them a while back about converting a TS-E from tilt/shift to tilt/rise and they

wanted $100 to remove four screws, turn part of the lens 90 degrees without

taking anything apart, and put the screws back in. Which works out to oh, $600

or so an hour for labor. So I'm reluctant to ship the lens down to Canon

Irvine without checking out alternatives first.

 

Repair shop recommendations also appreciated, particularly on the west US

coast. I'm familiar with Associated up in Portland, CameraTechs in Seattle,

and will give Camera Clinic in Sparks a call tomorrow based on forum threads

and photo.net's neighbor to neighbor section.

[HenryUK]

I don't know about your particular lens but all the EF lenses I've seen have a contact block fixed to the mount ring by two tiny screws.

 

The contacts are connected to the lens circuit board by a flexible circuit board soldered at both ends.

 

It is only a 10 minute job to remove the mount ring, remove the contact block, unsolder the connections and install a new contact block.

 

Canon will sell you the part quite inexpensively. Provided you have experience of delicate soldering and are very careful it should be possible to do it.

 

Henry

[sattler123]

Or you could just send it to Canon for repair - this should not be too expensive and certainly worth it!

[PuppyDigs]

Most Canon Service Centers have a minimum charge of $150 to $175. Realize these types of

businesses have heavy overhead: office rent, insurance, techs & counter help, constant

training, expensive gear, etc. I'd be surprised if they actually turned a profit. Most companies

look at service centers as a customer convenience, not a cash cow.

 

However, Canon USA Parts will sell you just about any part if you can describe it to them.

[alan_myers]

Todd,

 

To address your comments about the modification of the TS-E lens...

 

I would expect that total cost includes testing the lens afterward - on a collimator or whatever - to insure it's well aligned and within all factory specifications, and making any necessary adjustments.

 

So, it might seem a quick easy job, but may require some skill, knowledge and special equipment to be done right.

 

Like you, I'm not averse to doing something like this myself, but the $100 actually seems pretty reasonable to me, for this particular job.

[todd_west]

I think we can debate the business model for Canon service indefinitely. All I have to say on the matter is it's my personal preference to either do my own work or support shops which only charge for the work I want done (and don't sit on the lens for a while before they start working on it---the Canon tech I spoke said it takes two to four days just to get a lens into their "system" so that someone can look at it).

 

Henry, Puppy, thanks for the answers. Having taken a look at the contact retention screws on the lens mount I decided Steve at Camera Clinic was worth his price (about a third of Canon's minimum) and am shipping the lens down to Sparks.

 

Alan, converting a TS-E doesn't affect the unit holding the optics. The only way the lens can get out of tolerance through the rotation is if the interface at the back of the tilt block was badly machined. This is unlikely to happen and even more unlikely to make it through QA before the lens ships (squaring blocks with a fly cutter is a fundamental of milling). And, even if it did happen tilt could be used to compensate in the rotated position. So I, personally, am willing to dispense with any sort of fancy post-modification checks. As such, I'd prefer not to pay someone to do them.