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When will Sigma and/or Tamron produce RF lenses?

Started Jan 15, 2020 | Polls thread
RDKirk Forum Pro • Posts: 16,545
No change in protocol
2

Rock and Rollei wrote:

Certainly I got a 24-50 in 1991 - it fell apart a few years later. I also bought the Sigma 70-300 UC APO and the 18mm f3.5 - both of these were made inoperative by a later Canon change to protocols. The 18 was launched in early '92, i bought mine in May.
Early on, there was quite a lot of talk of how limited the lens situation was for EOS - something that seems preposterous now.

Canon did not change the communication protocol. That is witnessed by the fact that their very earliest lenses always worked properly, and in fact, my f1.8 50mm Mk I (metal mount) lens from 1986 still works perfectly with the EF adaptor on my EOS R cameras.

Canon did not change the protocol, they greatly reduced the power output of their cameras beginning, I believe, with the Elan 2.  When the 3rd party manufacturers reverse engineered the EF mount, they didn't take into account that native Canon lenses used far less power than the early EF cameras provided.  The 3rd party larger zooms, in particular, used every bit of power provided by the cameras.

When Canon reduced the power output of the camera (to reduce the size of the batteries), it left many of those 3rd party lenses gasping...

...but not all, which is also witness to the fact that the protocol had not been changed.

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RDKirk
'TANSTAAFL: The only unbreakable rule in photography.'

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