EF12 and EF25 extension tubes

[bruhnstv]

I was just gifted a pair of Canon extension tubes (EF12, EF25), and have discovered that they do not fit the EFS lenses I have that were made for 22.5x15mm sensors. There's a light baffle in the extender that's too close to the lens, or with too small an opening, depending on how you look at the problem. They do fit my EF 70-300mm IS USM, but it's generally the shorter focal length lenses I'm looking to use them with. Two questions: any idea why Canon didn't make the opening in the extension tube large enough (or far enough back from the lens plane) for the EFS lenses, and has anyone out there tried opening up the diameter of the baffle(s) in the extenders? (There appears to be nothing in the way of putting an extended in my lathe and boring out the baffle a bit... or I could sell this pair and get an inexpensive after-market set...)

 

[Big Mike]

Welcome to the forum.

You must have the older version of the extension tubes. The newer (II) versions are compatible with EF-S lenses. (maybe that's why they were gifted to you).

I found a tutorial on making the modification.

Modifying Canon EF Extension tube for EOS 300D lens