Bob Turner wrote: Would there be any benefits in upgrading to the Mk II versions of the Canon 1.4 and 2 extenders? I would use them with a Canon 70-200 f/2.8 and Canon 300 f2.8. I do stack them sometimes, depending on location, with the 12mm extension ring in between.
------- The optical advantages, if any, would seem to be marginal but as I suspect Bob is already aware, the 'new' extenders do not need the 12mm ring. Here is what EOS Magazine, Dec '02 had to say about 'doubling the double': "...Add another 2x extender and the effective focal length (of an already doubled 300mm - BP) will increase to 1200mm. "In practice, this only works with the MkII extenders, and only with two 2x extenders or a 1.4x extender fitted behind the 2x extender. You can't attach two 1.4x extenders together, or fit the 1.4x extender in front of the 2x extender" My own experience is limited. I have the 2x Kenko/Teleplus 7-element and the new 1.4x Canon MkII. Suffice to say that these can both be used with a 300mm f/4 IS, provided of course that the 1.4 is in front, with its 'nose' in the back of the lens. Its back end, being desirned to fit the camera body also fits the Kenko/Teleplus. One 'interesting' result is that you then get a one stop difference reported to the camera (by the Canon 1.4x - the Teleplus does not change the report). As I understand it, the new extenders have better dust proofing and of course we recently had some debate here about the proper lubrication for the improved seals. Bob Pendleton * **** ******* *********************************************************** * For list instructions, including unsubscribe, see: * http://www.a1.nl/phomepag/markerink/eos_list.htm ***********************************************************
