DIY: How to Turn a Canon Kit Lens From an EF-S to EF Mount


Last week we shared a guest post that detailed how using your kit lens isn’t so bad after all. Following in the footsteps of that post, we have a convenient little DIY project by Instructable user G. M., who decided to prolong the lifespan of his own kit lens, by converting his Canon 18–55 f/3.5–5.6 from an EF-S to an EF mount.

The steps involved are fairly straightforward, involving the disassembly, sawing, then rebuilding up of the rear-mount. But, straightforward doesn’t always mean simple. The tools needed include a phillips-head screwdriver, a small hacksaw, a flat file, sandpaper and quality epoxy glue. Beyond the tools, steady hands and patience is greatly beneficial.


We can’t speak on the quality of the resulting image, as he hasn’t seemed to share any, but it’s a neat little hack that at least makes sure your kit lens isn’t just gathering dust. To check out the full tutorial, head on down to the link below and get your toolboxes ready.

Canon EF-S to EF Mount by G.M. [via Instructables]

  • KTX

    Man WTF are you doing with that hacksaw? Just take out that grey coloured piece of plactic and be done with it. You can even reverse the procedure and restore it to its original state if you are not happy with the results…

  • KTX

    Oh, BTW here are the instructions for anyone who want’s to give it a try:
    1. unscrew mount
    2. take off mount and push the tabs of that plastic piece in direction of the hole – this will then push out the whole piece
    3. screw mount back on
    4. ???
    5. mount that thing to camera and profit the f-word out of it.

  • Marc Jones

    I’m guessing there’s crazy amount of vignetting when using EF-S lenses on a fullframe camera.

  • Jesse Baynard

    I’ve done this once to mount a cheap kit lens on an even cheaper Canon 10D (which was a cropped camera, but before the EF-S mount). I can’t imagine anyone doing it these days, especially not to put it on a full frame camera. Even if you have a classic 5D, you’d be better off putting on some old manual focus lens on than a modded kit lens with visible image circle. So unless you own a 10D, move along… and even then, it’s time to upgrade.

  • noisejammer

    The video shoes he modified an EF-S lens to suit the 10D (which has an APS-C sensor.) The reason would be that the 10D predated the invention of the APS-C mounts.
    I tried something similar with the EF-S 10-22 and mounted it on my 1D Mk IV. Several issues turned up. 1. When set to 13mm or shorter, the mirror would hit the last lens element (quite bad) 2. The image quality was poor (particularly on the edges where the CA was awful.) 3. Vignetting reduced the usable image to about 37mm diameter.

  • docholliday666

    …or you could not be cheap and go buy a (cheap) non EF-S lens. The quality’ll be better and you won’t smoke the mirror with some lens/body combos.