On Sat, 16 Aug 2003 Jim Davis <[EMAIL PROTECTED]> wrote: > "Gary Fisher" <[EMAIL PROTECTED]> > wrote/replied to:
> >I would think that should be ok. Both the Canon and the Sigma extenders have >protruding front elements. > Wow, I didn't know that. Is this a special Sigma > extender to go with their pro lenses or something. > I can't believe all Sigma extenders would not fit > anything but a Sigma Pro lens or a Canon L lens. <snip> > I want to get a 3rd party 1.4 or 1.5 extender. But > I want it to work with AF on my 100-400L IS. Does > anyone know if the new Pro Kenko extenders will do > this, or do they report the proper aperture? <snip> > What about a Sigma? Hi Jim, The EX Sigmas are designed for their high-end/pro lenses. They also fit the same Canon L lenses that genuine EF converters do. There's a compatibility chart on their US website: http://www.sigma-photo.com/html/pages/ConvComptChart.htm The Kenko Pro and Tamron SP (same TCs, just marketed under different brands) have the additional pins and report correct (i.e. adjusted) aperture to the camera just like the Canon ones do. So a 1.4x would report the f5.6 @ 400mm on your lens as F8 @ 400mm.... They do however work with all lenses, as they don't have a protruding front element. They are also pretty comparable to the Canon ones in quality (at least the 1.4x is, the 2x is reportedly so and I have no idea what the optical quality of the 3x would be like). >From the notes on the Sigma web site it sound like the Sigmas TCs report adjusted >apertures as well. Cheers Gary This message has passed through an insecure network. All enquiries should be directed to the message author * **** ******* *********************************************************** * For list instructions, including unsubscribe, see: * http://www.a1.nl/phomepag/markerink/eos_list.htm ***********************************************************
