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Rechip Old Sigma Lens So That It Plays Nicely with Your New Canon DSLR



Older Sigma lenses that were designed for Canon EOS film cameras often don’t work correctly when mounted onto a new EOS digital SLR, even though the newer bodies still use Canon’s EF mount. If you’re an owner of such a lens, you might have heard that you can send it in to Sigma’s service center for them to rechip it in order to make it compatible again.

Did you know that those of you who are handy with electronics can actually do the rechipping yourself at home? Photographer Martin Melchior recently did this with his Sigma 70-210 f/2.8 APO lens, and says that anyone with basic soldering skills can do the same.

The problem with the older lenses is that they use a different protocol for communication. Melchior says that you can get a lens and a camera on the same page again by opening up the lens and soldering in a microcontroller.


What you’ll need is a ATtiny24 chip, two resistors, and a capacitor. You burn the new firmware onto the chip and then implant the new electronics into the lens’ guts.

There’s enough room inside the enclosure for the new components, so the lens should look perfectly normal once you close it back up.

If this sounds like something you’d like to try your hand at, you can find the detailed step-by-step hack tutorial over on Melchior’s blog.

(via Hack A Day)

Thanks for sending in the tip, Pete!

Image credit: Photo illustration based on Surgery by Army Medicine, hack photos by Martin Melchior