Este artículo también está disponible en Español: Objetivo Konica en cámara Canon EOS (II).
After waiting for a couple of weeks, finally the extension tube set I ordered arrived. Just a little more hacking, and finally I have been able to finish my project. After my firsts tests, the resultas are even better than what I hopped.
These tubes are quite simple: there is a ring which fits to your camera, another one that fits to the back of a lens, and three rings (each of a different size), that can be screwed in between the first two; this is a very simple device, which can be mounted using a variety of combinations, to obtain the desired separation (between 15 and 64 millimeters, approx.) between the camera and the lens. These tubes do not have any type of electric contact, such as those found on similar products, made by Canon or Kenko; this means that any automatism is lost: no auto-focus and no diaphragm control. For less than 10 dollars, what else can you ask for?
Initially, I planed to hack an adapter to fit Konica lenses on a Canon EOS camera, using a back cap and a body cover, fixed together. But the body cover that I purchased took more than expected to arrive; and as I was playing with the tubes, I found an easier method to attach the lens to the rings: coincidentally, the back cover for the Konica lens fits perfectly inside the last ring.
I just had to make a big round hole to the back cover and glue it to the ring; a quick hack, but it feels solid enough to handle the lens without risk:
After a few initial tests, the results are quite promising. This picture shows a graduated ruler (in millimeters); and it was taken at a distance of about five centimeters (from the front of the lens to the subject, this is the shortest focusing distance that I could obtain). According to my calculations, if a 14mm subject occupies all the width of a 22.5mm sensor, there is a magnification factor of 1.6:1; not so bad...