Autofocus Microadjustment on the Canon 50D for Pentax Glass

In this second of a two-part series, I set the autofocus microadjustment on my Canon 50D for an Asahi Pentax-M 1:1.7 50mm K-mount. In the previous article, I had set up aperture and focal length in the Tago adapter's chip, so the lens would be recognized by the 50D.



There are plenty of how-tos and articles written about doing autofocus microadjustment for autofocus lenses, but there is not much out there for manual focus glass, which is why I wrote this article.

Setting up the Tago Pentax K to EOS Adapter

First off, welcome. I've been meaning to create this blog for quite some time, to help others avoid some of the pain that I encountered.

I have an old Asahi Pentax-M 1:1.7 50mm K-mount that was mounted to my old Pentax ME-Super in decades gone by. When I got my Canon 50D, I opted for just the body and have been buying L glass for it, but I never bought a 50mm lens to complement my kit. Thus the idea of buying an adapter to mount it on my EOS body was born.

After doing research on my options, I ended up searching eBay for such an adapter. I opted for one with an auto-focus confirm feature from DVDTechnik. The item I received was in good order, and the box had no English names on it, but the English instruction manual in pdf form that they emailed me was titled "Tago", and it mentioned that this had a generation IV AF emulator chip. In order to program it to work with my 50D's auto-focus indicator beep, I had to program the adapter using a difficult process that eventually swallowed 6 hours of my time.