help with canon 28-80mm lens cleaning!

GaelMonfils

Hello all.

I need a little help with dis-assembling a canon ultrasonic 28-80mm lens. I must admit my experience with camera lens' is somewhat non-existent, however, computers and IT are within my skill set so im giving this a go!!

The camera lens fogged up on the inside on several of the stationary and moving lens pieces. I have being able to take it apart and clean 2 lens but now im stuck. I cant for the life of me figure out how to gain access to the circuit board beneath the plastic housing (see fig 1). I have searched high and low online for any type of manual or instructions but to no avail.
I know serious photo people will probably be cringing at the thought of a complete lens novice taking apart a piece of gear but my mate who owns it has more money than sense and let me try to sort it!!

Any help greatly appreciated:)

aidanic

Hi,

Try this eBay item.

Aidan

PS You're nuts to do this...

zerohamster

Unfortunately lenses aren't like PCs and laptops to take apart but they are very order based if you get me.
You are unfortunately at the easiest part of disassembly and be prepared to spend a lot of time and have patience or you will break something.
before you go further if you have never taken a lens apart before take an A4 page and when you take out a screw or "set" of screws write down where they came from, the number of scews and draw a tiny box (like a square you would put on a for for a tick). Then use cellotape and put the screws on the paper and cellotape them down so that you will end up with a list of screws and where they came from as you may think you will remember where they came from but most likely something later on will make you forget.

To clean the elements dont use much force on the inside as the coatings are usually quite soft inside and too much force could potentially rub it off.

Ok now on to what you need to do next from the look of it.
1. If you haven't already then unscrew the two small screws holding the contacts to the mount (if it is a seperate part on that model as some aren't).
2. the back cover on the inside of the mount should be popped out but this can be slightly difficult and if not careful you could damage the contact FPC and/or rear element. there will usually be three clips that have been glued lightly to the mount part).
3. If that cover can be popped off and isn't part of the mount then you should have access to the circuitry and should be able to remove that after disconnecting the FPCs and below that the screws holding the rear barrel to the front (depends on the lens).
4. Remove the rubber ring and if you can see guide slots with screws then make sure to remove them as this will allow you to remove most of the back of the lens on most models.
5. For the rest take it in steps and work your way down the lens. you can also unscrew the front element by using a friction tool so you can clean the back of the front element and the front of the focus group (If I remember correctly).

By the way take a photo of the barrels as you remove them as there are usually 3 different ways they can slot in and there are usually at least 3-4 barrels which means about 27-81 possible combinations with only 1 correct one so although it will take extra time to take a photo to show the rotation of each barrel in relation to eachother it will save overall time and much frustration if you get the wrong combo of rotation and dont know why.

I do repairs myself so this comes from experience but I do this a lot so take it slow and cautious if you want it to come out in one piece

I have one of these at home and it is a pretty basic lens to disassemble and assemble but I dont have it at hand so Im trying to go from memory/basic lens order so if one or two of those steps dont fit just skip that part as it may not be required/need to be done later.
One important rule you should set yourself is never force a part of the lens, if it doesn't come out after you remove screws/other parts then go back and look again for anything you have missed that would prevent the part from being removed but always be careful to use just the right amount of force as you dont want to break a part or tear an fpc inside because you pulled something out too quick.
If you get to a stage where you think you will damage something if you try to continue then stop and reassemble the lens as 95% of the time you will damage or crack something by forcing it.

Good luck and let us know how you get on.