Canon EOS 450D / Rebel XSi: How to repair the defective autofocus

A DSLR camera is a fine thing. My Canon EOS 450D (also labeled as Canon EOS Rebel XSi) gives me a lot of pleasure even with its standard kit lens Canon EF-S 18-55mm 3.5-5.6 IS.

After three years there has been the first defect now. During a mountain hike the autofocus stopped working.

This article outlines how I solved the problem for about $10. And even if your AF is currently still working, it may be interesting to you how to disassemble a Canon EF-S lens.

» Um die deutsche Version dieses Artikels zu lesen, bitte hier klicken.


Autofocus is dead. What to do?

At first I thought that my camera got too much splash water, but even some days later the autofocus remained dead.

Well, not all dead. If the focus was completely retracted, it was possible to focus exactly one time and then the AF was dead again. This meant that at least the focus motor should still be intact. I suspected the lens to be faulty, because everything was working perfectly when it was switched to manual focus mode.

So I tried a friend’s lens on my cam and behold: the AF was working! Now it was clear that my EF-S 18-55mm lens had to be defect.

I was already out of warranty for 1 year, so I had three options:

  1. Giving the lens to a repair center. Too cost-intensive.
  2. Buying the successor (IS II). Matter of expense: about $200.
  3. Disassemble the defective lens and have a look inside.

Since I had nothing to lose I decided to have a try with option 3. Fortunately, because today I hold the EOS in my hands and it’s working perfectly again with the old lens.

If you have a similar issue, the following may be helpful to you. Everyone with some manual skills should be able to reproduce it since no soldering rework is necessary.


Step 1: Disassembling the lens

It’s surprisingly uncomplicated to unscrew the lens if you are using a fitting miniature crosstip screwdriver (screws are tightened quite strongly).

It’s important to use a screwdriver with the right tip which is size PH00 in this case. Don’t work with the wrong tool, you won’t be happy.

At first you have to loosen the four screws on the backside and swing open the top cover. Carefully detach the flex cables (FPCs) from the white connectors. After that you can take off the controller board together with the top cover.

On the picture on the left the cover of the focus gearbox was also removed. This is not necessary and is not recommended! The whole gearbox unit is taken off as a single piece by removing the two silver screws.


Step 2: Replacing the defective FPC

As I had the lens disassembled so far, I immediately spot the broken flex cable which connects the focus position slider with the controller board. Bingo!

Apparently this is a fatigue failure as the FPC is bent and relaxed with every in- and out-move of the lens (during zooming, not when focusing!). Quite a questionable construction from Canon (keyword “planned obsolescence”).

If it is looking similar in your case, you can proceed as described below.

1a) Removing the broken FPC
On the picture in the middle, you can see the defective flex cable on the left-hand side (it only seems to be flexed sharply, but it is really broken straight through). In the background there is the silver slider which has to be removed now (in the picture on the left, the slider is top right). It is maybe a bit hard to unbolt the two screws of the slider. Afterwards the glued FPC can be removed with help of needle-nose pliers when the lens is fully moved out (i.e. maximum zoom).

1b) Ordering the spare part
Now it’s time to obtain the spare part. I got hold of a Canon spare parts list (see the German comments). Every single part of the lens is descripted there in an exploded view.

Fortunately, the broken FPC for the autofocus can be ordered as a single spare part. The part number is:

FPC Focus

You can obtain the spare part directly from an authorized Canon service partner. You find one through your local Canon website. Navigate to Consumer > Support > Product Repair and choose Digital SLR for the product type.

When you do not essentially want an original Canon spare part, you can get the flex cable quite cheap e.g. from eBay. Especially when ordering in China you may have to consider quite long shipping times.

1c) Mounting the new flex cable
The spare part comes with an adhesive film on its backside and can easily be attached to the right place, which is defined precisely by a rectangular deepening. Just remove the protective foil and patiently place the FPC with tweezers. The lug of the slim part leading upwards is also glued on. Be careful for the tappets of the lens body to lock into the holes of the FPC (possibly it’s necessary to bend the FPC a bit).

Finally the FPC should firmly be pressed down with help of cotton swaps or similar.


Step 3: Reassembling the lens

Now it’s nearly done. The reassembly is naturally done in reversed order:

  1. Screw the slider in place.
  2. Mount the focus gearbox with the two silver screws. Mind the long plastic axis to be locked into the short gear collet because otherwise the focus won’t work at all.
  3. Reattach all FPCs to the controller board. Insert the board into the lens body. Pay attention to the pictures and be careful not to break anything. The FPCs may be quite rough-running, they have to be inserted carefully and as far as possible.
  4. Put the grey plastic ring on top (fits only in one single position) and screw the top cover in place with 4 screws.

Now it’s time for a first operational test. In my case the autofocus worked again straightaway (don’t forget to set the slide switch back to AF if necessary).



For me it was worth the effort. I’ve saved 90€ and my old lens is as good as new again.

I hope this documentation is also useful for some of you out there and I am looking forward to your comments. And please feel free to complain about translation mistakes. This would be a help for me, too.


Further reading

113 thoughts on “Canon EOS 450D / Rebel XSi: How to repair the defective autofocus

  1. Thank you very much for this write up! Saved me lots of money just before Holiday :) Bought flexi off ebay for £3.60 in UK.
    All the best!

  2. Thank you very much. All works. Your method is the simplest, it avoid to unmount the front part of the lens like many others said. You are the best. Thanks again (from France).

    • Good tuitorial, mine had exactly the same issue and following your instructions fixed it perfectly for a few euro.


  3. Hi: I have a 450D and will not take pictures unless it is in auto. In the other settings I have shutter it twice. I have tried cleaning the contact and changes the lens but it makes no difference. Any ideas? Roger

    • Try another lens. If the problems still occurs, it’s probably the camera’s fault. In this case I have no other idea besides removing the battery and maybe doing a factory reset.

  4. I have the same lens but the focusing only sticks at the infinity end.
    Once the lens focuses all the way back (infinity) it will not move any more although I can still hear the motor give a slight whirr when I press the shutter button to focus.
    Focusing works well at all other position although at the 55 end it seems to also stick in the middle focus position.
    I have not opened the lens yet.
    Does any one have any idea as to my lens problem?

      • It was a broken FPC
        It’s fixed now following your excellent instructions.
        Tip to others:-
        Keep your lens in manual focus setting when removing or refitting focusing gearbox.
        Rotate the focusing barrel slightly to facilitate fitting the the two halves of the focus driveshaft back together. One part slides over the other.

  5. The symptom was the AF focus drive would only run in one direction. Move it back in MF and it would wind in again on AF but not out. The instructions are brilliant, I bought my replacement from ebay and it took about 30 minutes to fit. It had snapped in two exactly as the photo here.

  6. Thank you very much! One more happy reader here. I took my time disassembling carefully and practiced a lot before peeling off the adhesive protection but it went fine in the end.

    Only tip: don’t forget to align the motor shaft when replacing the motor. I did not and could start half the work again.

    Thanks again!

  7. After much googling about my lens, which will auto focus in one direction but not the other, I came across this post. I opened up my lens as per your instructions and sure enough came across the exact same problem. I’ve just ordered my spare part on Ebay for $13, and cancelled a $60 order for a used replacement lens. Thanks!

  8. thank you for your blog. save me almost 50dollars. this was very helpful…
    thanks again

    carlo v. of batangas philippines.

  9. Hi Marphy,
    Thanks for this – my autofocus packed up while on holiday and I found your blog – had to resort to manual focus for rest of trip and just did not realise till then how much I relied on the autofocus function for rapid picture taking. Got home and did not have a lot of luck with Canon UK but e-bay provided a solution and I got two FPC’s for just under £2 (less than 1.5USD) so that was a result. I did not notice immediately but the FPCs have small holes in them which with the aid of pointed tweezers makes removal from and reassembly to the main control board very easy. It was a bit fiddly more getting the lens re-assembled but well worth it and it’s now working fine again. How long it will last with non Canon parts we will see.
    Well wort the experiment and the saving of £150 – thank you very much for the extremely helful blog.

  10. Is the FPC the same one for Canon EOS 1000D? my auto focus hasn’t worked for at least 2 years and as I need glasses my photos are getting worse and worse! I really need the auto-focus function. I tried looking at Canon spare parts but the FPC looks as though it is different than the EOS450. Can you advise me, before I order the 450D FPC? :)

    • Which FPC to use does not depend on the camera but on the lens.
      If you have the standard EF-S 18-55 IS on it then it’s exactly the FPC as mentioned. For 18-55 IS II and 18-55 without IS the partnumber is different.

      • Excellent! Thanks Marphy. Ill try and get it done before Christmas! Thank you again for your help! :)

  11. Works like a charm, thanks again! If you have problems removing the flex cables (FPCs) from the white connectors (Step1), use a needle, every cable has a small hole: put the needle in this hole and gently pull the cable out of the connector. Also usable to attach the cables to the connectors after replacing the FPC.

  12. Thanks for all the info and also interesting feedback from other contributors.
    Great instructions and I followed as far as removing the 4 screws. Then came across a problem not mentioned by any of the above – I could not get the flex cables to leave their connections. They are of course very fragile and I am worried about the amount of force that may be necessary to get them off the white connectors. Is there a knack to this or do I just bite the bullet and pull hard?
    Thanks in advance and for all the time and patience that you have put into this article.

      • Thanks – just ahead of you here. I decided like most others, nothing to lose so went for it with a pair of flat tweezers and some less than friendly persuasion. All off now and, sure enough my new best friend, the cable is completely broken as you said. Just ordered a new one on Ebay.
        I presume that similar force will be needed to replace the cables on the white connectors.

      • Thanks again.
        Job done. As expected, tricky to get the part positioned exactly correctly. The adhesive has a mind of its own and wants to stick elsewhere if you take your eye off the ball.
        Difficulty experienced in re-attaching the FPC’s to the circuit board until I found that a small screwdriver, with care, would exert enough pressure when applied to the tiny hole in the FPC just to the rear of the connecting end. That may assist someone else following our footsteps.
        Meanwhile, back on the ranch, my pal has had his EOS 450 for four years….watch this space.
        A thousand thanks again. The part cost me around £3 on Ebay and arrived in 48 hours but I now have a fully functioning camera. Next step is to locate an adaptor ring to enable me to use my old Pentax ME Super lenses in manual setting.

  13. Hi Marphy,
    I came across your blog after googling for a solution to non-focusing 18-55mm kit lens on my 5 year old 450D. I tried everything (new battery, menu resets, new firmware, etc) and nothing would work. I tried another lens and it worked so it was not teh camera body but the lens.

    I checked repair costs in UK and was around £60 …ouch. One can buy a new lens for £100. Since I did not wish to use the lens in Manual Mode, I bit the bullet and bought the ribbon cable from ebay on the assumption that this cable was broken.

    I already had PH0, PH00, PH000, etc screwdriver bits and most critical tool….a curved slim tweezers.

    To be honest, I used the link you gave in this blog to the site as it has detailed arrows and circles in the guide. Successful ! The lens fully works again. 20 minutes max.

    When the ebay cables arrived, I dissembled the lens and yes it was a broken focus cable. Peeling off the broken cable was quite tricky as it was well stuck to the body but with patience and use of the curved tweezers, I eventually removed it (5 minutes).

    The hardest part was positioning the new FPC into the correct position on the lens body. What I did was “practice” the placement before peeling off the protective backing sheet. I must have spent good 5 minutes trying to get it right. There is no easy way as the space is very very tight. The only tip I have is to put the lens to infinite focus point (creates more room), and then pre-curve the new FPC to shape it to the lens body curve. Then, I peeled of the backing and started to position it (with the tweezers) and managed to place it perfectly into the original space. Probably more luck than skill. I used a microfibre cloth and wrapped it around the other end (non pointed) of the tweezer and gently pressed it down onto the new cable. The cloth helps to keep the gold contact clean and prevent scratches.

    Once the FPC was stuck down, I operated the zoom barrel in/out to see how the FPC bent and noticed how it would kink in one place. This would create a weak spot over time (and that how the original broke). So, what I did was to “shape” it while if was fully bent such that the FPC did not have a sharp kink but a gentle bend. That is, I took out the kink. I used the curved tweezers to do this. Oh did I mention how invaluable this tool has been ? :) I Zoomed in/out a few times and the FPC seemed to flex on a gentle curve now. Hopefully, this will give it longer life.

    I re-assembled the lens…no issues encountered. Switched the MF to AF and attached the lens to the body and turned it on. Autofocus worked first time ! Wow !

    Oh, I still have a spare FPC :)

    Many thanks for your blog !

  14. I am having problems too, and I came across this webpage… I don’t think my ribbon cable is broken, but I did notice that gear that runs up to the gear box assembly, only seems to be “half” a full 360 gear. Is this broken or is it designed like that?

  15. Absolutely brilliant information on repairing this lense. I am delighted you took the time to help out other who have this problem. Thanks again.

    Regards Darren.

  16. Thanks for sharing this. Your tutorial has just saved me some money too. Have to say not a great design from Canon though, that thin ribbon is bound to give out at some point.

  17. Hi there. Perfect information. I wonder if someone here knows if this wire problem is still present in the newer lenses…mark 2 and 3? Are they worth buying? I mean, I like to use it longer than 2-3 years!

  18. Thanks you very much for useful advices! I took out the broken FPC but i don’t know where I can buy a new one? The nearest service centar for me is in Belegrade (I am from Bosnia), and on their site i can’t find the part which i need, so I don’t know whether they wont to sell me a FPC, or they will needed from me to bring the lens them to repairing…I don’t wont buy a cheap one on e-bay…. Thanks a lot!
    I’m sorry on my English, I hope you’ll understand…

    • Just write an e-mail with the part number and ask them to send the part to you. That’s the way I did it, too.
      If you want to buy from eBay, I think you don’t really have to worry about quality.

  19. thanks marphy. helps me a lot. just cost me around $15 for the flex and shipping. but when i asked a repair shop nearby, they’re gonna cost me around $50 and i’ll have to wait 1 month for the repair. KUDOS to you….

  20. Many thanks – just fixed mine. Part cost £2 off ebay. Little bit fiddly and need bright light these days but amazingly it works!

  21. Thanks for the help!! $17.03 and 3 days later we are back to taking pictures in focus. Had some testy screws but got thru it! Will remember your blog with every snapshot from now on.

  22. Great found your blog halfway through repair, gave me great confidence
    One source in Uk £19
    Purchased 2 for £3.06 from China
    2pcs CANON 18-55MM IS Lens Focus Zoom Flex Cable Ribbon Replacement Repair Part .
    eBay item number:171061653431
    Fiddly job, I am 66 with bad arthritis and failing sight. If I can do it so can you.
    What have you got to loose!!!!

  23. Thanks for the share Marphy….what if the lens fails to focus ?, that is, the lens motor went to a direction, stopped and stayed there without trying to reach focus ? what should I check ?
    thanks in advance..

  24. We have a 5 year old Canon Rebel XS (1000D). The autofocus also quit working recently. It won’t do anything when in auto. When we switch it to manual, we can take a picture, but it’s still blurry. Hoping that we can use this to fix it. $500 seems an awful lot to pay for something that only works for 5 years! Will try it and hopefully it will work!

  25. Great stuff. I was sweating like mad taking it apart but after initially being p***** at my Canon lens failing so quickly, your advice has helped me fix it good as new for £3. Cheers buddy!

  26. Thank you so much for this tutorial! My wife and I just fixed our lens and saved a ton. You get good karma for life!

  27. Do you have any information regarding “Err99″ when the zoom is in the 18 to 24 range? Above that, the lens works fine, but i can’t take a picture if i go wider than 24…

  28. Great tutorial, thanks a lot! Two years later and still helping folks. I also had a Rebel XSi that had the same problem with the flex cable. I managed to get the replacement part for about two euros…a LOT cheaper than a canon dealer. Your instructions were great, and easy to follow. I had no problem removing the old FPC and placing the new one. Straightforward, genius fix! Thanks a million, the kit lens is really useful and I’m glad to have it back in my bag.

  29. Thank you very much for this! Took it apart and found the broken cable. Ordered a new one and gonna put it together as soon as it comes, gonna work like a charm, Im sure about that!

  30. Thank you very very much for this! I had exactly the same problem with the kit lens on my Canon EOS 450D. The autofocus didn’t work at all, so I’d have to switch to manual focus, turn the focus ring, switch back to autofocus and the lens would then focus – sometimes.

    After reading about this very common broken ribbon cable problem (it’s all over the internet – nice one Canon!), I listened very carefully to the lens as I zoomed in and out, and could hear what sounded like a couple of bits of broken ribbon cable catching on each other – a faint click. So I took the lens apart and it was immediately obvious that this was the problem.

    The replacement part (I’m in England) cost me all of £3.23 (with free shipping) from here:
    No idea of its quality or longevity, but at that price I can afford for it to fail yearly. I’ve had my 450D with its 18-55mm kit lens for about 3 years, and only recently bought a second lens, so it’s had a fair amount of zooming in and out to wear out that crappy flimsy bit of ribbon cable.
    One thing I would point out: it is impossible to remove and replace this part without removing the gearbox. With the gearbox in place, it’s impossible to get access to the two screws holding in the metal finger/contact thing on the rotating part of the lens. Also, one of these screws in my lens had a blob of thread-lock on it, making it almost impossible to remove. But with gritted teeth and some brute force, I managed to budge it, without mashing the screw head. Getting the new part in place, waaay down in the guts of the lens, was a bit of a nightmare – you kinda skip over that part in your instructions. I also bought some tweezers:
    which really helped – unless you have microsopic hands, you’ll need tweezers to hold screws, pull out the old ribbon cable part and insert the new one. And they’ll definitely help when plugging in those five tiny ribbon cable ends into the miniscule sockets on the round circuit board. I feared I might have killed one or two of those cables – they needed a fair amount of ‘persuading’ to go into the sockets. But no – I put the lens on my camera, and hey presto – it all works perfectly!

    – Paul

    • I’ve just re-read this, and smiled at the bit where I said “but at that price I can afford for it to fail yearly”. That was more a reference to the TIME invested in pulling apart and fixing the lens rather than it taking me a year to save up three quid!

  31. I just bought my camera from a friend, and the autofocus is dead, the manual focus works fine, and when replaced with a new lens (rented) everything is in working order. You said that your AF, would work once, then cut out. Mine just does not work at all. When in AF mode, a “busy” message pops up with the flash lightning bolt symbol. Do you recommend trying your strategy? Any different suggestions? Thank you for such a helpful step by step !!

    • Just have a try and open your lens up. No big deal.

      According to your description, you may have another or an additional defect. Possibly your focus gear is broken?

      I would be happy if you could give some feedback after opening the lens.

  32. Hello: Important Question: I’d be grateful if you could answer.

    My camera was also dropped. I don’t know if it’s an autofocus issue however, even on manual focus I cannot get a clear picture, it is always blurry.

    I will check the flex cables, but I have a feeling it might be something else..could it be? I don’t mind not having autofocus, I don’t care for it. But I at least need my manual focus to work! I have a Canon Rebel t3i

    Thank you.

  33. Hi, I dropped my camera and since then the auto focus on the 18-55 lens is not working. Camera works fine with other lens. Manual works . I opened up camera and FPC autofocus is not broken as far as I can see. What else could be the issue and how do I spot it. Thank you for your help

  34. I have Canon EFS 18-55 mm lens and it stopped working on auto focus as one day I hit the lens on the object and since then it has stopped auto focusing. It is working on manual focus but then requires lot of time and effort to focus. There is one click sound when I am manually adjusting the lens focus. It seems something is broken inside but not sure what? Can anybody please help me to restore the lens in a better way. Thanks

    • Either you give the lens to a repair center or you pluck up courage and open the lens yourself.
      If you choose to try it yourself I would be happy if you can give some feedback about what was wrong in your case.

  35. I would like to thank everybody for their comments, as I have exactly the same fault with the Auto Focus and following the procedure as laid out I have managed to disassemble the lens and hey presto the FPC was broken as said in the text. I have sent emails enquiring about a new part and hopefully will have one within the next week or so. Then I should have the lens up and running again the same week.
    Thanks once again

  36. Thx for you big help.In Romania the FPC Focus spare part was 30 Euro incl. VAT.
    And it took 45 minute to have autofocus back in business.

  37. I’m thinking about screw extractor, not about screw driver.. I was looking on eBay but I’m not sure what diamet of that screw extraction tool I need cause I don’t know size of that top screw, one of four. I really need help cause in that screw I have just big hole.. :'(

  38. Hello, first I was trying to repair lens by myself and that was not going in good way.. can you provide me help cause one of four top screws I was not able to unscrew and my friend tried to unscrew with using force and that was more complicating my problem.. I am repeating, last week I bought set of screwdrivers and another 3 of 4 I took it out and now I am quite sad cause I am not able to see what problem is inside my lens..

    I made research and question what I am asking now is what kind of screw extractor I need to take that last screw and what kind of screws I need to buy now and put on place that damaged?

    I made research and I need opinion do I need this screws?
    Canon 155A &188A Hot Shoe Base Screws

    Please help me cause I really miss my old photographing with my 18-55mm II lens.. :(

  39. Thank you so much!!! I ordered the ribbon on ebay for 14 bucks (it somehow came w/4 ribbons.) Took about 15 minutes start to finish…works great!

    • To add to my last post…the old cable wasn’t visibly broken but clearly was. I couldn’t get my big fingers in the lens enough where I felt I could adjust the new cable if the sticky tape was exposed…I slipped it in without exposing the adhesive (I did expose smaller adhesive strip. I can’t imagine it ever shifting around…I wonder how essential the adhesive is for long term stability.

      • For a precise and properly working AF I recommend to stick the FPC to the lens with the full backside as well as the little tap, i.e. to expose all adhesives step by step when installing it. However, you can try it your way of course and improve it when you are not statisfied or further problems occur.

  40. This is an excellent post – many thanks. Following your instructions I have removed the defective FPC and am currently waiting for my replacement. – Do you think strengthening the weak spot of the replacement FPC with perhaps insulating tape would be of any benefit ?

    • Good question. I don’t really think so, because it is simply a fatigue failure due to repeating stress on the part… Maybe it would even be counterproductive as this stiffens the flex cable and thus increasing the occurring forces.
      Anyway, thanks for your commendations!

      • Update* – I have now fitted the replacement FPC and everything is working fine. With regard to the strengthening of the FPC your advice was spot on – once fitted I could see the full movement of the FPC and stiffening it would not have been a good idea. Once again many thanks for this informative article and your advice.

  41. My 18-55 stopped auto-focusing today, checked online, found this article…thanks very much for the info! It was a huge help!
    Something I’ll ask/mention though…and it’s concerning the bottom part of the flex cable (the large surface (about 2.5cm x 1cm) where the ‘fingers’ contact). In your article, you don’t give any special instruction on removing that portion of the faulty cable, so I had assumed it just comes out easily. Also, in the picture, yours appears to be made of the same stiff material as the rest of the cable.

    The issue is that the 2.5cm x 1cm portion (in my lens, at least) is made of very thin material and the entire back of that section is stuck on with adhesive. It did come off, but it was difficult….so difficult that I can’t see how you could ever stick the new one on in that tight spot and have it properly placed.

    Can you confirm if yours was flimsy and ‘stuck’ firmly to the hard black plastic surface?

    I’m wondering if in a later version of the lens that they changed the design so it’s now nearly impossible for the average person to replace this part….?

    • That would be interesting. Can you provide a photo of the lens with removed FPC?
      As far as I can remember, the FPC stuck quite well, but it was no big deal to remove it from the lens.

      • Hello.

        Here is the lens, while apart:

        The FPC did not fully break, but was kinked and cracked (visible in 1st picture).

        And here is the piece I’m speaking of:

        The darker coloured section on the right is the thickness of the FPC, but the area where the fingers slide (lighter coloured) is very thin, almost like foil, and was stuck on with the same adhesive that is used further up the FPC at the square with the two tiny holes.

        Even pulling carefully, the FPC tore several times while removing it. As said, since the article did not say anything in particular about how to remove the part of the FPC in the 2nd picture, I assumed that it was not difficult at all. If the replacement part sticks on in the same way, I’d think it would be nearly impossible to get it placed in the perfect position and not mis-alinged…..since the adhesive was very strong and you’re working in a tight spot, down inside the lens…

        Hopefully it’s easier than I assume…..I always fear the worst :-)

      • Just ensure that the area is clean before you install the new FPC. As there is a deepening that exactly defines the FPC position, it should not be too hard sticking the new FPC to the right place. I think you will make it. ;)

      • *update* It is a little tricky to get that piece aligned properly (since it has the sticky backing) but I got it. It’s not in exactly the right position, but it’s making contact and working A-1. Thanks for taking the time to post this great info on your blog…it’s helped a lot of people!!

      • Tricky getting the FPC out indeed. I had to use needle nose pliers to get the cable out as very firmly stuck and a tight working space. Take care! There is a small plastic lug (extension) which the kink section sits behind (like a guide rail). Unfortunately, when trying to get the firmly glued cable out this lug broke and that was that! So, be very careful getting the FPC out you don’t inadvertently break the lug :(

  42. My camera wont focus in manual focus either and I have the 300 zoom lens also and the autofocus won’t work with either. Any suggestions?

    • Sounds like a defective body. Try this:

      1. Put a friend’s working lens onto your camera body and try AF.
      2. Put your “defective” lenses onto a working camera body and try AF.

      If your body seems to be defective, try to reset to factory settings.

  43. Hey, thanks for the informative article! This saved me a lot of money and made me learn a whole lot more about my lens!

    Here’s my problem: I found the broken flex cable, replaced it, put everything back together perfectly but the problem is exactly the the same. Autofocus works when you manually set the focus ring far away, then it focuses once and stops working. I checked inside again – the new flex cable is working and everything looks fine.

    I’m not sure what is causing this problem.. any ideas?

    • Thanks for your feedback.

      Please double-check the focus FPC for correct and complete insertion into the connector. And also have a look into the German comments, there was a similar question here.

      Looking forward to hearing from you!

      • Hi,

        Thanks for replying.

        I disassembled the entire lens and checked it twice just now and everything seems to be exactly how it should be. I tried checking the German comments as well, and this is what I found:

        A. FPC has come out of the plug contact.
        — No, it is firmly connected in the contact.

        B. Copper cable is broken, although the optically FPC is still intact: FPC exchange on suspicion.
        — I do not see any broken cable anywhere (except for the original one, which I replaced with the new one)

        C. Focus engine and / or transmission is defective (see here ).
        — I was worried about this, so I opened it all up again; however it’s perfectly alright and isn’t broken in any way like the pics show.

        D. Fault lies not with the lens.
        — Other lenses work just fine, so I’m sure it’s this particular lens and not the camera body.

        Right now, my only lead is assuming that the cable I got (from eBay) might be defective and I might need to try a new FPC from a more reliable source. But it looks fine and doesn’t seem to be damaged or anything.

        Since the auto-focus problem is exactly the same as before and nothing seems to be fixed, I’m wondering if something else is also defective, apart from the cable. You can hear the motor trying hard to focus (random buzzing sound), yet when I set it to manual, everything moves perfectly without any part getting stuck.

        So I guess I’m back to square one. If you have any idea about this, please do suggest some solutions.

  44. Hey! Thank you for your wonderful piece of information. I’m actually stuck at removing the bottom part of the FPC. I can’t seem to remove the slider. Can you help me with it? Cheers!

  45. dude! thank you! just took the lens to bits and this is exactly the issue. very poor design – saved me a couple hundred bucks servicing this thing!

  46. What you did was terrific but someone who is not very skilled mechanically (like myself) wouldn’t ever try what you did. Further, someone unskilled could do serious damage to the lens. If you go to single central focus, does the camera still focus fairly well? I tried my telephoto lens and it focused somewhat erratically. Then I tried the kit lens and all the autofocus red lights lit but didn’t flash. I’m not sure the problem is the same as yours though it may well be. Nine months ago I paid over $150.00 to repair the auto focus and again it’s not working properly. I love the camera but I’m disappointed in Canon’s failure to prevent this from happening.

    • Thanks for your feedback.

      In my case and as mentioned in the text, the auto-focus did work for one single time if the focus wheel was manually set to infinite focus before (not depending on focus mode). So it was actually possible to still use the auto-focus but in a quite annoying way. The focusing of the defect AF felt not different.

      If you do not have exactly the same lens (EF-S 18-55 IS) it’s quite hard to guess what’s wrong with it. If you are lucky you open the thing up, swap a broken FPC and everything is fine again. I think $150 are worth a try!

      Please let me know when you find out something interesting.

  47. Hey Marphy! Googled the FPC autofocus issue and came across you blog entry and bookmarked. Ordered the right tools and the spare part from H.Lehmann LTD (as I’m based in the UK) and followed your instructions (very helpful photos by the way). It worked for me! Felt quite exciting taking the lens apart and putting it back together again. Thank you very much for posting this info – much appreciated! Kudos to you! ;)

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