EF-S Surgery

Hacking / Converting a Canon 18-55mm EF-S lens (non IS) to fit a Canon 10D

First and foremost, nobody at devilgas photographic will take any responsibility whatsoever for any damage caused to any equipment as a result of following the text and/or images found upon this page. We accept no responsibility for the content presented here. If you are chimp enough to break anything you or somebody else owns because you decided to follow what I've done, that is solely down to you. Quite simply, you are responsible for your actions.

Ok, now the stupidly necessary legal bit is squared away, down to business....

This work is not original. It came about after reading how to modify the above lens on Bob Atkins site, specifically, here

What is presented here are my findings on attempting something uncannily similar.

First, and foremost, the following butchery is done to the cheap, plastic 18-55mm kit lens, not the more expensive image stabilised (IS) version. I'm reliably infomed that the IS version has extra electronics - presumably the IS itself - mounted within the plastic that gets chopped off.

I won't go too much into the nitty gritty of the lens mounts and mirrors, but suffice to say that the kit lens supplied with the 300D can be modified to fit a 10D. The EFS mount contains additional material to protect the lens elements that protrude further from the lens body than standard EF lenses. It is this protrusion that causes problems with EF mount cameras, specifically the mirror. The 10D has a smaller mirror than say the 1D or film cameras, which will *just* miss the glass elements when it operates. What we do here is to remove the protecting material to enable the lens to mount to a standard EF lens mount.

This lens has not been tested on anything other than a 10D, and I'm led to believe if it's tried on a 1D etc then the mirror will strike the glass elements at the wide angle setting. Certainly, looking at where the elements end up at full WA, they protrude significantly past the electrical connector block. Seeing this, it's highly likely it will hit the mirror on anything other than a 10D or possibly the D30/60.

The Surgery
First, make sure you have a small jewellers Phillips / cross-head screwdriver. I used a No.00 x 50 (see the photo a bit later on) which was part of a Precision Screwdriver set from Focus DIY (UK). This perfectly fit all 6 screws you need to play around with. There are 4 small screws and 2 very small screws to remove. If you have the wrong size screwdriver, you will likely strip the head and that'll be end of sports.
The 4 small screws are quite easily spotted as they are nearly at the 12,3,6 and 9 o'clock positions on the mount as you look at it. The screws are highlighted below in red.

 4 large screws

The 2 very small screws are neatly hidden and hold the electrical connector block in place.

2 smaller, hidden screws
All of the screws need to be removed. Start with the electrical connector ones. The screws don't appear to have any thread lock on them as they undid quite easily. You will need to be careful not to slip with the screwdriver as the screw heads are easily damaged. Don't be tempted to use a flat blade screwdriver that 'fits'. This will most likely spoil your day.
If you're not confident in removing the screws perhaps a local jeweller may help? Just remember though, the risk is yours, not theirs.

Once all of the screws are removed, store them safely! They are very easily lost so put them into a sealable container. An old film (remember that stuff?) canister will do.

screws, removed

You should now have the EFS mount free from the lens:-

EFS mount

lens without EFS mount

It's worthwhile removing the small rubber gasket, but it's probably not necessary.

rubber gasket

Now you need a few junior hacksaw blades - I used 3 as the material the mount is made from (some kind of graphite plastic) gets through the blades at quite a rate. I opted to use the blades without the hacksaw handle to get a little more control. Took the best part of 30 mins to carefully cut through the mount. You should now have the following pieces.

the various bits

Dont' get rid of the inner piece just yet as it can be re-used to make the lens look a little nicer later on. If you haven't done so already, get rid of the rubber bit. It's now simply a case of using some sandpaper to smooth everything off and get the inner ring you've just created flush with the surround.

EF mount, cleaned

I cleaned all the excess material off using a toothbrush under running water, and obviously allowed it to dry thoroughly before the final step.

Now it's just a simple matter of screwing it all back together (there's a pair of thin metal gaskets that need to be lined up) and building the courage to try it on your expensive 10D

finished article

on the camera

Tested mine at full zoom and full wide angle and there were no dodgy sounds of breaking glass, so, the surgery was a success!
Judicious use of e-bay and a grand total of £70 (the screwdrivers cost £7.50!!!) has seen me getting a wide angle lens for the 10D.

Now some extra, probably only cosmetic, surgery. The inner piece can be re-worked to help hide all of the electronics. I have no idea if this will make any difference to the image. It may reduce internal reflections in the lens, then again, that may not be an issue.
The little plastic piece can be remounted on the inside of the new EF mount. First though, you'll need to remodel 3 parts of it. Initially, you'll need to create a cut out so that it may fit around the plastic piece that holds the elctronics connector block.

lens insert

Then, you will need to cut out the innermost rim so that the lens can move freely the full length of the tube. The image below shows the job half complete. Hot melt glue was used to hold the two plastic pieces together. Very much a Blue Peter special. (Blue Peter - kids TV show from the UK that used the immortal phrase on most projects "double sided sticky tape for speed")

trimmed insert

Finally, you will need to remove about 5mm or so from the bottom of the tube so that the lens doesn't hit the base of the tube. It'll all be pretty clear what needs to be removed when you try it.
I'll be perfectly honest, I used a small pair of wire cutters to do this. Probably not the best tool for the job but I couldn't be bothered spending a lot of time on it. It does explain the strange marks on the surround though.

lens with insert


Neither myself,, my family, my friends, my pets or my vampire bat take any responsibility whatsoever for any damage caused to anything or anyone by duplicating what I've done. If you feel confident in not destroying your expensive digital imaging equipment by trying this little ditty, that's your choice and not mine.

v1.11 4th Nov 2007 Extra stuff about IS added - thanks to Nathaniel Courtens
v1.1 16th Sept 2004 Re-used the inner piece to tidy things up a little
v1.04 6th Sept 2004 Final photos added. Cheers Mr K!
v1.03 6th Sept 2004 Lens mount notes added
v1.02 5th Sept 2004 Typos fixed
v1.01 5th Sept 2004 EF compatibility text amended
v1 5th Sept 2004  
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