I’ve been a bit remiss getting to this post, since I’ve had the lens back for a couple of weeks now. Anyway, here it goes.

A few weeks back I reported that my 100-400 suffered from a problem common to the EF 100-400 f/4.5-5.6L, the zoom clutch failed.

…the first indication of a problem is that you begin to see bits of black stuff stuck to your lens barrel…

For those who’ve never had this happen to them the first indication of a problem is that you begin to see bits of black stuff stuck to your lens barrel between the 100 and 135mm marks. This is actually part of the locking mechanism breaking down.

If you start seeing this, I’d suggest having the lens looked at, since it’s likely going to be much cheaper to have the clutch rebuilt without having to replace the lens barrel too. However, mine operated in that state, leaving bits of black stuff on the lens barrel for 6 months or more without any other indication of a problem. In my case I didn’t realize what was going on until the clutch failed completely and in doing so damaged the lens’s outer barrel prompting another expense to be added to the repair bill.

Being that my 100-400 was long out of warranty—and quite frankly the warranty period for Canon’s lenses, especially the L ones are in some ways obscene, but that’s another story—I elected to take the lens to a local Canon authorized shop instead of shipping it off to Canon. The center I choose, Southern Photo Technical Service, came highly recommended by several local photojournalists that I know. Doing so certainly saved me from paying for shipping. Even better, the quality of their work seems to be every bit as good as people told me it would be. Of course, these guys are building beefed up Nikon D3Ses that have custom designed shutters and tweaked AF algorithms so that has to say something about their skills.

expect to spend at least $250 if the zoom clutch fails completely

For my lens, the repair ran about $275 and took 2 weeks. It likely would have been even more inexpensive if I had known what was going on and had the clutch taken care of sooner.

I have no idea how the turnaround time compared to having Canon do the work. On one hand I didn’t have to ship the lens, so the work was started faster; on the other, Southern Photo had to order parts and that took some time. That said, Canon’s service center (at least the New Jersey one) has been very quick in the few instances I’ve had stuff go back to them. I’m betting that the time was a wash either way.

The lesson to take away from this:

• Be very careful with your EF 100-400, especially in dirty or dusty environments. Dirt and sand can get in the clutch, and I think that was what started mine going down the drain. In addition, I’d probably stay away from really tightening down the zoom lock; enough to be snug but no more since that could also contribute to forcing the material to adhere to the lens barrel.
• There are no home remedies for this problem; it needs to be addressed of by a service center. Even being extremely careful isn’t necessarily going to save you. My 100-400 that failed is always kept clean, and wiped down with a slightly-damp soft-cloth after almost every use. It still broke.
• When something seems a bit odd, it might be a good idea to have it looked at. In this case, when the clutch fails completely it can damage the lens barrel necessitating another part being replaced.
• Canon really needs to release a new 100-400 (yes even after this it’s still my favorite long lens) that is better engineered to not fail like this. Though I’d still prefer a push-pull zoom than a ring controlled zoom, at least at this focal length range.
• If you’re out of warranty, and even if your gear is under warranty and you’re in the South Florida area, Southern Photo Technical Service may be a good solution for getting something fixed quickly. It doesn’t hurt that there a factory authorized service center for just about every major camera manufacturer. For example, they did a rush shutter replacement on a D2H (luckily they had the part) for a friend of mine in under 24 hours.