Canon 100mm USM problems

Hi there everyone.
I'm new here in this forum. I have a couple question to ask regarding the Canon 100mm Macro.

Last December 2008 I bought myself a 2nd-hand these 100mm Macro from eBay . It cost me AU$550, which is quite a bargain for a used Macro lens.

To my surprise, I found that the Autofocus doesn't work at all. I'm very sure that I have switched the AF on, but it just won't work. The AF won't hunt anything. Even if I switched the focus limit, nothing works.

Other than the AF issue, everything is fine. I can still do MF. Glasses are clear no fungus or dusts, no physical scratch. But I just feel ripped off. I paid that amount of money for a lens that doesn't have AF. I have tried to contact the seller, he was willing to reimburse my money.

The seller claimed that he bought the lens around 3 years ago from local store, but he only used the lens for 1 year & since then he never used it & stored it. He admit that when he sold the lens, he didn't try the AF so he didn't know that the AF was broken.

After all of that, I decided to bring the lens to a repair center. I didn't go to the Canon department because the lens' warranty already expired & they quoted me AU$350 for a repair

Instead, I went to the lesser of the evil, a local repair center authorized & certified by Canon. They quoted me AU$290 for the repair, that includes parts replacement for the AF module & labour costs. I've paid $99 the Down Payment FYI. The repair center said that they need to order parts from Canon directly because they don't have the module. I gave them my lens on 2nd January 2008, but up until now the repair center hasn't received the replacement AF module. I feel like a donkey now...

So that's a story of my stupidity, but I have some question to ask:
1. Does the broken AF problem very common in this Canon 100mm lens?
2. I was wondering if the broken AF actually caused by storing the lens & not using it for a long time, therefore the AF module somewhat deteriorates after certain amount of time?
3. How come it takes very long time to order a replacement part from Canon? It's been a month since I gave them my lens for repair but up until now my lens is just a sitting duck on the repair center's shelves waiting for a new repair parts.

4. Lastly, probably not that relevant, but should I just cancel the repair & just live with the MF?

I feel really pissed off now. I paid AU$550 for a broken lens which was also my mistake being to impulsive, another AU$99 for the down payment of the repair & now the lens is gathering dust on someone else's house. I have a lens but I don't have it in my possession.

I apologize if I rant too much here, I'm just a newbie asking for a help.

Thanks in advance everyone.

virsago_mk2 ,
Welcome to the forum

Sorry to hear about your problem.
If it happen to me I personally would just live with it as a MF lens and wouldn't put any money into it. After all 99% of all my macro photos if the lens isn't on 1:1 Life size I manually focus anyway. I only use the AF when I am not doing macro photography.

Good luck with it

First,
Welcome to the forum! this is definitely the place to ask. I'm with John on this one, I'd live with it as a Manual lens. first because you will get better results with MF for macro, and secondly I'm cheep and wouldn't be willing to pay that much for the repairs.

so I would call up the service center and tell them I'm gonna have to charge them rent on the lens! LOL no seriously, if they don't have the part by now... they aren't planning on getting it anytime soon. get your lens back in your possession, if you really want the AF to work and are willing to pay their prices tell them to call you if they ever get that peice in stock.

Good luck with it. Sorry you have had a few bad experiences there. and again welcome to POTN! this is the greatest forum on the net!

Thanks for the input guys.

Not to be picky but I don't think anyone have answered my first 3 questions...
So please, if anyone can help me.

I've called the repair center & email them that I have the right to cancel the repair if they don't make it until this Friday 13 February 2009. If they can't fix my lens until that date, screw them then.

BUMP please...

1. Broken AF is not a common happening on the 100mm Macro to the best of my knowledge.
2. Sitting around is unlikely to break a working AF. Could possibly be issues with lubrication, but unlikely. There's nothing else that would "age," and there are people with a lot older lenses than that who've never had issues.
3. Don't know. It would seem to me that sitting and waiting to order parts is a function of the repair center. Waiting for ordered parts to arrive could be related to your location, and I'm afraid I don't have any experience with how that would work where you are.
4. I like AF, too. I use my 100mm macro for more than just macro.

I think most service centres only carry commonly used spares so the fact that they are waiting for parts really answers #1- no I've never heard of it before.
Brian V.

OK I think I finally found the problem with my lens.

The reason why my AF doesn't work is caused by the flexible cable that connects the main PCB to the USM stator.

Anyone know where can I order this cable online?

I can definetely confirm now that it IS the flexible PCB that caused the AF not working.
When I opened the lens, I found 4 thin flexible PCBs:
- 1 connects to the AF/MF switch. This one works fine, the lens recognize the signal when I switch to MF or AF.
- 1 connects to the electromagnetic diaphragm. This one works fine as well, as I can still change the aperture from the camera.
- 1 connects to the inner side of the focusing ring. This one I believe transmit the focus signal, which I think still works fine as well. Because my lens on MF still can transmit the focusing signal to the camera.

- Lastly, the problem, 1 that connects to the USM ring stator. This one should transmit the signal to stator which then powers the rotor to move the focusing glass. For some reason, the rotor in my 100mm macro doesn't move at all.
According to my discussion with kimmik from the email, he mentioned that to determine if the USM is still repairable or not is to listen when in AF mode, is there any faint noise that indicates if the rotor is actually moving or not. In my case, I didn't hear any noise from the rotor.
So I can conclude that it's the stator that cause all of this broken AF problem & needs to be replaced, to be precise, the flexible pcb on the stator.

And thanks for those replacement parts store info guys. Unfortunately the fotogeeks doesn't sell the specific parts I wanted. Even when I called Canon Aussie just now, Canon said that don't sell individual PCB parts. They only sell the whole USM focusing unit 'for just' freaking $230 now. So I said, meh for that.

I just found out from the Canon Lens work III book, there are only 2 sizes of USM ring unit. There's MI type, the most common one with diameter 62mm. And the other one the larger LI, with diameter 72mm mostly used on those white lenses.

Now I know that the 100mm Macro uses MI type, so I figure out it might be better to find other cheap ring type USM lenses & then I'll just canibalize the USM unit to the other.

And just on my luck here, I found the old EF 28-80mm f/3.5-5.6 USM mark I on eBay for just mere AU$70 + $13 shipping.

So what I'll do is I'll be waiting for the lens to arrive, then starts replace the stator unit on my 100mm Macro with the new one from 28-80mm.

Sounds a lot of work to AF on the lens- I only ever use MF for macro (and just about everything else) but good luck with it all.
Brian V.

virsago_mk2 wrote in post #7394638
I can definetely confirm now that it IS the flexible PCB that caused the AF not working.
When I opened the lens, I found 4 thin flexible PCBs:
- 1 connects to the AF/MF switch. This one works fine, the lens recognize the signal when I switch to MF or AF.
- 1 connects to the electromagnetic diaphragm. This one works fine as well, as I can still change the aperture from the camera.
- 1 connects to the inner side of the focusing ring. This one I believe transmit the focus signal, which I think still works fine as well. Because my lens on MF still can transmit the focusing signal to the camera.

- Lastly, the problem, 1 that connects to the USM ring stator. This one should transmit the signal to stator which then powers the rotor to move the focusing glass. For some reason, the rotor in my 100mm macro doesn't move at all.
According to my discussion with kimmik from the email, he mentioned that to determine if the USM is still repairable or not is to listen when in AF mode, is there any faint noise that indicates if the rotor is actually moving or not. In my case, I didn't hear any noise from the rotor.
So I can conclude that it's the stator that cause all of this broken AF problem & needs to be replaced, to be precise, the flexible pcb on the stator.

And thanks for those replacement parts store info guys. Unfortunately the fotogeeks doesn't sell the specific parts I wanted. Even when I called Canon Aussie just now, Canon said that don't sell individual PCB parts. They only sell the whole USM focusing unit 'for just' freaking $230 now. So I said, meh for that.

I just found out from the Canon Lens work III book, there are only 2 sizes of USM ring unit. There's MI type, the most common one with diameter 62mm. And the other one the larger LI, with diameter 72mm mostly used on those white lenses.

Now I know that the 100mm Macro uses MI type, so I figure out it might be better to find other cheap ring type USM lenses & then I'll just canibalize the USM unit to the other.

And just on my luck here, I found the old EF 28-80mm f/3.5-5.6 USM mark I on eBay for just mere AU$70 + $13 shipping.

So what I'll do is I'll be waiting for the lens to arrive, then starts replace the stator unit on my 100mm Macro with the new one from 28-80mm.

Great troubleshooting! I would have done the same thing so I don't think it was a waste of time at all. Does anyone know where you can order these types of lens parts? I would also be interested.

tundraman wrote in post #7434666
Great troubleshooting! I would have done the same thing so I don't think it was a waste of time at all. Does anyone know where you can order these types of lens parts? I would also be interested.

Thanks mate.

Unfortunately I'm on the same boat as you, I don't know where to order a specific type of the lens' spare parts.

Some of the boardies recommended fotogeeks site, but they don't sell the USM ring stator alone. The Canon Australia itself only sell the whole USM units (the stator, the rotor + focusing unit), and they won't allow me to order just the flexible PCB that I'm looking after.

The best bet for me was to buy a cheap, working lens from eBay (which I found one) that have the same USM ring unit, then cannibalize it with the other.