I have npt used the Sigma, but do use the Tamaron 2.0 TC. with my Nikkor 300/4 lens.
The auto focus
and mettering functions all work. I do notice a lack of sharpness using the doubler
but for the price
I can't complain.
Gary
>
> Has anyone used the new Sigma 1.4 APO TC with the Nikkor 300/4? If so, how
> have the images been? I wish to keep my lenses all Nikon, but there is no
> 400/5.6 AF option other than third party. The Sigma TC will preserve AF and
> all metering funtions, according to Sigma. I would love to hear from anyone
> who has tried this combo.