Photography - Seeing what's inside a canon auto focus lens

Opening up my old camera in an attempt to fix a stuck lens didn't end well, but it did make me want to open other stuff.

A mouldy $5 canon EF 35-80mm zoom seems like a good candidate.

I actually made it work better than it did when I started.

That's officially a successful repair.

We don't see many of those around here.

Odd feeling.

It turns out I wasn't being all that original when I used a lens cleaning cloth to make my macro lens hack light tight. It seems canon does something similar with a rubber band.

I attacked the rubber grip of the lens by lifting it up with a small flat head screwdriver, and sliding it up to reveal the three screws that control the zoom function.




Once that was done, the lens started falling apart. All it took was finding where the screws were in the first place. All the places I was told to start by the Internet were all false leads. I'm guessing things like lenses are made by the lowest bidder at the time, so these things probably change design all the time.

The only real stumbling block was this very fragile looking plug.

Luckily I had uncounted them when I pulled apart my point and shoot canon digital, and discovered they weren't really all that fragile.

I covered it with a folded bit of paper so the pliers wouldn't scratch the circuit off and pulled.




I also tried to avoid touching anything that looked like it might be copper. I have a feeling that touching stuff might lead to corrosion.

Probably just being paranoid, but it wasn't any really effort to avoid it. I should buy some cotton gloves for this kind of thing.

The little plug looks like this when it's unplugged.

Robot's are probably better at putting stuff like this back together, so I took a lot of photos as I was unbuilding it, so that I might have a chance of putting it back together.

That's a tip.

Take lots of photos of things as you pull them apart.

One part that was really fragile was this little bit of kit.

It's like a switch that drags it's contacts along a curved section of circuit board tracks so that the contacts keep in contact when you rotate the lens to zoom.

Or perhaps they adjust the aperture as you zoom, as I've noticed the available aperture range changes from one extreme of zoom to the other.


Who knows what it's really for, but I bent it convincingly out of shape when I was putting the thing back together.

I managed to fix it, but two of the pins will never be the same again.

This is the rear element. (the bit you can see a lens in on the left)

It's a cluster of ... three I think it was... lenses (two at least, but I think one was made of two), that I think also contains the aperture control.

The aperture control stuff must be in there, because there was nothing else with electronics in the lens.

I think this is me taking apart the lens that was really two lenses.

This things all had mould, but the other side of the one you can see in this pic had the most.

This is what I decided was the aperture bit.

I hope this isn't too technical for the reader.

Is bit even a word in this context...

Anyway, the remarkable thing is, after wiping down all the lenses with a lens cloth, it was actually an improvement.

That's the before and after shots with this lens.

Most of the milkiness is gone, but there is still a bit of mould on the front bunch of lenses, but I think I might hack them off and convert this thing to a macro lens.



I've been reading up on lenses, and how to hack bits off lenses that you dont want, and turn them into lenses that you do want.

Anyway, not a bad outcome for a $5, brand name, auto focus, zoom lens.

I cant wait to cut bit's off it.




120 things in 20 years - Where you will still find someone who thinks a lens doing it's auto focus thing is excitingly like having a robot. You also might find someone interested in photography trying to open a lens to see if there really is a man inside who does the focusing. (there's not by the way)