Why would anyone buy this Sigma over the Nikon 70-200mm f2.8??

"Paul Furman" wrote in message
...
nospam wrote:
In , Peter
wrote:

The Kenko extension tubes and 1.4 extender, work fine with my 70-200mm
f2.8,
which is af-s and VR.

do you know which pin is missing?

No! I am simply curious about it, I once asked Kenko but received no
meaningful answer. Hey, the thing works. The Nikon contact may be
reserved
for a future feature.

i'm curious which pin it is. it's probably one of the pins used for
additional power or one for teleconverters, neither of which would be
needed on an extension tube. here's some more info on the protocol:

http://forums.dpreview.com/forums/read.asp?forum=1030&message=26958036

The newer line of tilt/shift lenses have electronic apertures rather than
using a lever like most Nikkors or completely manual stop down on the lens
like the previous T/S models.


That may be the reason.

Thanks, Paul

--
Peter

David J. Littleboy wrote:

"Ray Fischer" wrote in message
...
lofi wrote:
In my humble experience of comparing side by side Nikon and Sigma lenses
the
actual performance of too many Nikon lenses leaves one wondering what one
is
paying the Nikon premium for.

Every once in a while I think about possibily trying a Sigma lens.
Then I discover that they're still a bunch of incompetant and
dishonest creeps.

Huh? Sony changes the behavior of their mount and it's Sigma's fault?

Did Sony's lenses stop working?

And
Sigma offers to fix it for free on all current lenses (hint: the
discontinued lenses long predate Sony's acquisition of Minolta) and Sigma's
problematic? You're dead wrong on this one.

Not convinced.

--
Ray Fischer