Anyone tried fixing camera lenses?

[AndyC_772]

I have a Canon EF 100-400 L IS (mk 1) which I bought new for a holiday some years ago and which has only seen occasional use since then.

Last week I tested it and found the image stabiliser not working; the image jumps violently up and down at roughly 1 sec intervals, and the camera shows an aperture of '00' each time, which is what it does when there's no lens attached at all.

With IS turned off it works perfectly.

Unfortunately this model was discontinued shortly after I bought mine, and it's no longer supported by Canon. They can't provide spare parts any more.

The lens is optically perfect and definitely worth repairing if at all possible. I'm at a bit of a loss as to what might be wrong, but ordinarily that doesn't stop me attacking any faulty product with screwdrivers. Maybe it's just a loose connector, or a mechanical component needing a clean and a drop of oil.

However...

A camera lens is a hugely complicated assembly, requiring careful alignment which I can't possibly replicate if there's any specialist optical equipment or software required once it's been reassembled. Even without that particular obstacle, cameras and lenses are a nightmare of tiny screws, flexi circuits, fiddly little connectors and other fragile and easily lost components. It's not something I'd take apart for fun.

I've already ordered a replacement lens (I've upgraded to the mk II), so the question is: what to do with the old one?

Try and fix it, and risk reducing it to a pile of expensive looking junk, or perhaps a lens that looks fine but will never take a sharp photo again?

Or sell it as-is, and hope that someone out there wants an excellent lens (without IS, of course) for what will no doubt be a ridiculously cheap price?

[mag_therm]

I suggest to try on one of the Canon gear oriented forum.

There may be smaller service providers known on the forum  who specialize in repair of vintage and obsolete  Canon .
(There is one such, for Pentax K mount stuff which I collected.)

 It sounds like a worthwhile  lens to try to repair.

[james_s]

I don't know how these work exactly but going off an educated guess and the behavior you describe, I suspect the camera is not seeing a signal from whatever sensor it uses for feedback on the image stabilizer mechanism. This could be a bad sensor, or more likely I think a bad connection. I would start by cleaning the contacts of the connector where the lens interfaces with the camera and see if that makes a difference.

[cozza]

I had a Canon EX-1 Hi8 camera many years ago, with separate lenses (VL mount, specific to this camera body).

The camera suffered from surface mount electrolytics leaking in the camera body (100s of them) and from memory, there were a few on the PCB's in the lenses too.

May not be relevant, just a thought.

[wilfred]

I would also suspect the lubrication of the image stabilisation mechanism may have been inadequate or has dried out over the years. I did a quick search and this lens does seem to have a history of this problem.

You really should take this query to specialist Canon camera forums. I also found this video on Youtube. I am not sure if it is your exact lens. It is about the repair of a Canon lens with IS problems. Hope it helps you understand your problem a bit better at least.

[Koray]

I have repaired many manual focus lenses and few autofocus lenses before. It is doable, but it is nearly impossible to put them back together without dust particles left inside. Particularly zoom lenses are the most difficult beasts. The video sent by wilfred shows the extent of the work. Therefore I wouldn't dismantle down to IS unit. However, you can still try dismantling the lens up until the optical block and see if there are any loose connectors (it happens). Aperture 00 value points at a main PCB problem, it sounds like the lens doesn't get stable power when IS is on. Maybe it is a cracked smd capacitor shorting the main power rail? You may be able to track shorts on main PCB.

If it can't be fixed with that, you can put it on ebay, but with a fixed price. Auctions on broken/faulty gear do not always end with a fair price. I would look at the lowest price on a good working copy and then list it at half of that price as a buy it now auction for one month length. Put auto-relisting and when it is sold you will be notified, maybe in one month, maybe in a year. This is how I do it.

K.

[RoGeorge]

I had a similar malfunctioning on a Nikon D90 sitting unused for a long time.  It turned out the culprit was the contact pins between body and lens.  Those were golden plated contacts, all looking clean to the naked eye, yet once I gently clean them with a cotton swab moisten with izopropyl alcohol, it all started to work normally again.

[david77]

I've tried my hand at repairing a few manual Pentax lenses, I'd say the chances of a successful repair are 50/50. If it's a valuable lens that you care about try and find an expert.

[james_s]

I have repaired many manual focus lenses and few autofocus lenses before. It is doable, but it is nearly impossible to put them back together without dust particles left inside.

Might not be too hard to build a cleanroom chamber adequate for this. Make it out of cardboard lined with plastic sheet, use a small blower with a HEPA filter to maintain positive pressure. With something small like this you wouldn't need a very big chamber to do the job.

[shakalnokturn]

Taken a few compact optical zooming digital camera lenses appart and one Canon with I.S. (can't remember the model).
It isn't that easy, and as stated by Koray, the real tough point is getting them back together without contamination.

The Canon lens was randomly failing to autofocus, disassembly showed that the cause was a broken flex print cable leading to the autofocus motor. I can't remember for sure but do think that the I.S. had a similar setup.

[AndyC_772]

Thanks for the insight and suggestions everyone, much appreciated.

I agree there's about a 50% chance that I might be able to get the lens apart, find something fixable, and reassemble it back into an optically sharp and usable piece of kit - and, of course, a 50% chance that I'll turn it into a pile of worthless scrap.

With that in mind, in the end I decided to play the odds, and list it on Ebay for about 50% of the cost of a good lens. This gives me the same expected return in monetary terms, but with precisely zero hours of my time spent peering down a microscope thinking "where did that tiny screw go?".

It sold within 5 minutes of listing.

[Rasz]

$800 OLYMPUS M.Zuiko Digital ED 12-40mm F2.8 Pro Lens with mechanical damage. ripped in half internal micro multilayer pcb

sadly video is of the 'look what I can do' with speed up work dubbed by shitty background music

[EHT]

Ah yes, I have the same EF 100-400L lens, not sure if mk I, II etc - it is the push/pull type. On mine the AF was not working. I managed to fix it by replacing the ultrasonic motor, part found on eBay. It was a real fiddle to work out the part number and verify it was the right thing, but luckily it worked out and was < $100 for the motor, appeared to be new-in-box as described.
The above video on YT by the eastern european shop is very good quality. I think they show the assembly and disassembly. I couldn't have done it without these. I disassembled it in stages and put aside the screws from each stage separately. To get to the AF motor I didnt have to fully disassemble the lens, but I suppose you will to get to the stabiliser.
I love this lens - really good quality glass. The new version is something like £1,500, so getting this old one with a slightly worse IS (1 stop?) was very cost effective!

I've repaired a different Canon lens which had a snapped ribbon cable.

I have another Canon zoom which works but is very loose -i.e. if you point it downwards, the force of gravity extends it. If anyone know how to tighten that up, would be appreciated.

[onsenwombat]

Doable for sure, but the more features such as autofocus and stabilisation the lens has, you're exponentially (made this theory out of hat) decreasing your chances of getting anything more than fillers for your bin.
Problems you might encounter:
PT-screws locked in plastic destroying that flimsy base either on their way out or back in.
Obvious issue of just adding a bucket of dust and smudges around the lens.
Messing up with those image stabiliser mechanics and/or the electronic aperture mech.
Screwing up royally the lens element alignments, resulting in all sorts of out of focus issues (de-centering, not focusing properly at all..)
Destroying some plastic parts when you're trying to dismantle the beast.

If you have any proper use for the lens, I'd just go without the stabiliser. If you want to take it as a hobby project and accept the likely fact that the lens comes out worse/bricked, go for it.

[EHT]

From my experience with the same lens, the risk is mostly that you wont be able to reassemble it correctly. Watch the videos carefully, and pause each step. Take pictures of the disassembly and number the parts.

You also have to take the risk that the fault may not be the stabiliser unit if you order it . First step is to see if you can get a replacement IS unit for a reasonable price

[drhex]

There is a chap in Germany who repairs a lot of lenses, you may want to give him a ping.
Karl Michael Beutler
Fotogeräte-Service
Weiherstraße 3
D-86500 Kutzenhausen / OT Agawang
Telefon: +49 (0)8294 5114743

[Mechatrommer]

i've repaired few of my canon lenses (including the "red rings" bought 2nd hand).. most of them are due to broken flex cable. chaotic behaviour and comm not detected as you described are symptoms. bought replacement cable from ebay market. so i learnt lenses need to be stored with their flex cable straighten inside, usually at its longest focal lens position, but thats depend on lens type, if you opened it you'll know at which position it should be stored. store them with flex cable maximum bending, they will short lived. while disambling, mark the mating parts with some visible marker, esp barrels that you need to twist to unmate, its dog disappointment when you fully reassembled it just to figure out it cannot swing full range due to wrong mating alignment, and then need to dissasemble again just to correct it. on black part i will just use liquid correcting paper as marker, its sloppy but thats what i have. careful of the shims and spacers, dont lose them, and note their positions, your lens will be out of focus calibration if they are misplaced. be careful not to mess around  delicate part such as aperture diaphragm, you'll need similar delicate hand and microscope to reassemble them if you screw them. as said, this repair procedure is strictly requires clean room with zero dust, in normal room or home lab, dust will get inside guaranteed, but i noticed no visible image degradation if you have slight dusts got inside, but remember to be as cleanest as you and your room possibly can while doing it, one tip for cheap repair in your home lab is to turn off all equipments that can cause air (hence dust) to circulate such as ceiling or wall fan and air conditioning, let the dust settle for few minutes and do the repair, but you will be bathed with sweat all over, so dont let the sweat get inside too. if you have winter like we dont, i think its better to do during that time. be ready with lint free tissue, lens cleaning fluid, and quality Lenspen is a must, you are going to need it if your fingerprint got onto the lens. cleaning fingerprint with normal tissue and cleaning fluid wont simply cut it, esp on internal lenses, your images will become hazy even if you thought you've cleaned them well enough. ymmv, cheers. ps: and yes, if you can find in youtube your particular lens such as posted by wilfred, you'll know what you are dealing with and can save you lots of learning the hard way during the repair process. another random 100-400 lens repair...



edit: try cleaning the contact pins first thoroughly maybe they became stained and lose contact, pushing them few times, and rotate all the rings may remove the long storage stain etc. may be there can easy fix before going deeper the fungus hole...

[AndyC_772]

Thanks for the suggestions folks, but...

...I decided to ... list it on Ebay... It sold...

My old 100-400 is happy in its new home, and I've been thoroughly enjoying the 1DXmkII and 100-400 mkII that I bought to replace it.

[Mechatrommer]

It sold within 5 minutes of listing.

oh my congratulation to the lucky buyer but if the lens developed fungus during storage, he may have more fun time cleaning them off (not really a daunting task actually if you have the right cleaning tools )

[Mechatrommer]

My old 100-400 is happy in its new home, and I've been thoroughly enjoying the 1DXmkII and 100-400 mkII that I bought to replace it.

just remember to store it not with the flex cable got maximum bent, one not really bulletproof tip, but could help, is to look where the internal lenses got farther from the camera body, usually thats when flex cable is straighten out and thats how you should store your lenses, i mean any lenses with flex cable inside, nikon canon L or non L everthing. if you are unsure, just put it in middle focal lens position, to lessen the cable tension, to ensure longevity. my fixed lenses with china flex cable have been going on for years now without needing 2nd replacement (i still have spare cables during my first purchase, just in case) ymmv.