First impressions:
I have used both the 1.4 and the 2.0
converters from Sigma. I mainly used them in combination with the Sigma 70-200 2.8 lens. Since I
also own a 80-400OS, this TC solution has become a bit overdone, so I ended up
using the TCs for extreme focal lengths on the 80-400OS. This allowed me to take
pictures of the moon with an 800mm f11 equivalent or with the 1.4 TC 560mm f8
lens.
On the 70-200 2.8 it was still possible to use auto focus because the
resulting combo was f5.6, but on the 80-400, the maximum aperture will not allow
you to auto focus. And with such a focal length and aperture it is quite
difficult to focus manually even with a bright viewfinder like on the D200. So, as a
conclusion, a TC is a cheap solution to get a long focal length, but
with some serious constraints (slow resulting lens, smal aperture and picture
degradation). With the 70-200 2.8, I had very decent pictures even at
400mm 5.6 but the picture quality was just acceptable when used in combination
with the 80-400OS.
Pros
- cheap way
to have a virtual long lens
- very good quality when used on fast
high end glass (70-200
2.8 for instance)
- AF still possible if fast lens (2.8 or
4 in conjunction
with 1.4)
Cons
- picture
degradation (higher on the 2.0 than
on the 1.4)
- no auto focus if resulting aperture
smaller than 5.6
A few pictures
The 1.4 TC
The 2.0 TC on the D70 with the 70-200 Sigma lens
An example of a pic at 400mm, TC 2x on the 70-200 2.8 lens
A moonshot with the 80-400OS + 2x TC = 800mm with manual focus, hand held
