Copenhagen Calling - Again

[richardHaw]

nice red caps 

[Kim Pilegaard]

Thanks for this account of a nerdy weekend. I always love to read these reports.

I wonder what are the real benefits of chipping extension rings? I suppose they cannot transmit information of the lens attached to them?

[Jakov Minić]

Kim, they are not only nerds but extremists.
You got it right, you need to chip each extension ring for its dedicated lens. In other words, every lens has its dedicated extension ring.
I have one chipped for my 105/4 micro, and regardless of the lens I put onto it, it will read 105/5.6 in the EXIF.
I am thinking of reprogramming it to my Heligon if possible?

[Bjørn Rørslett]

Jakov, just take the PN-11 with you and I'll reprogram it for your Heligon.

While it is true you need pass-through contacts for the extension to recognise its host lens, having a dedicated extension isn't a bad idea at all. You get the opportunity of having the correct EXIF data incl. effective aperture given the magnification and cater for any change in focal length, the widest range of metering options, etc.  M/M2/E-2/PK rings are inexpensive and easy to bring with on a trip.