Poll: What lens do you want to see next?

40d_dane wrote:

John Sheehy wrote:

Another thing I'd like is switches on a TC to determine what is reported and whether or not to trick the camera, like the Kenko Pro DGX TCs do. When no reporting is used, one might still want the identity of the lens changed in the metadata to reflect the presence of the TC, so you can tell when it was used. It might also be useful to change the identity of the lens by the TC to allow separate MFA settings for the lens when used with the TC.

That will never happen ! The "reporting" system works just like Canon want it to work and they don't want it to work any other way. What happens is that the attached TC will short 2 or all of the 3 extra TC-contacts on the lens in the lens mount. The lens then changes its reporting to the camera accordingly. Prior to the mk III TC's no Canon TC contained electronics. The marketing material on the mk III TC's say that they actually contain active electronics. You can disable/modify the TC reporting by taping the 3 TC contacts in the lens mount. Use isolation tape to make a 1.4 TC invisible. Use conductive tape to make a 2x TC "report" as a 1.4 TC. Please note at any experimentation with taping contacts will be entirely at your own risk !

The whole point of doing things electronically is to avoid having to use things like tape. I only tried tape once, and didn't like it.

Anyway, my main concern is not for total TC transparency; I just included full non-reporting for completeness. I'd prefer to always have the correct focal length and f-number in the camera display and in the EXIF information. I would, however, like the option of having a choice in whether or not the actual f-number affects attempted AF behavior (of course, it can always affect actual performance). Having a mixture of TCs (Tamron SP 2x, Canon 2xIII, Kenko Pro 300 DG & DGX) and lenses of various behaviors (no TC contacts, TC contacts, TC contacts but tricky self-reporting), there are pluses and minuses in the various combinations, but they are inconsistent, which is problematic.

Even total non-reporting is annoying as far as EXIF is concerned, it is sometimes helpful; if you have the aperture of a lens at its sweet spot, and decide that your next subject is too distant and you want to use a TC, simply inserting the TC actually opens the physical aperture, unless you remember to stop down, possibly making the use of the TC almost pointless, at soft-wide-open (better sampling of less analog detail).

With all of these variations and quirks, TC use is a jungle. So, I'd be interested in TCs that could pretend to be the lenses themselves, and let the user determine how the camera sees the combo, and how the system behaves. Could not a TC designed to do so intercept the signalling and change it with little delay?

As you may know, the Kenko Pro 300 DGX TCs allow correct reporting, but AF when it should not be allowed (reported f/8 will allow AF on f/5.6 cameras). Is this possibly a step in the direction that I am talking about?