Vivitar or sigma

"< db1 >" <dvdb @yahoo.com> wrote:

The Vivitar is junk, or worse.  It has appalling build quality and
sample variation is huge.  It also appears under the Cosina, Soligor and
Phoenix brands, so make sure you avoid all of these.  It briefly
appeared, a few years ago now, as a Tokina.  However Tokina dropped it
from their range when they made their own 20-35mm f/3.5-4.5, which is an
excellent performer for not much more money than Vivitar.  

The Tokina 20-35mm f/3.5-4.5 was discontinued late in 2000 and the
replacement is a 19-35mm f/3.5-4.5 which is optically near-identical,
but has a polycarbonate barrel to save weight.  The 20-35mm f/3.5-4.5
had metal construction, and in my opinion it is a slightly better buy.

The 20-35mm and 19-35mm f/3.5-4.5 Tokinas have excellent sharpness and
contrast.  Whilst there is some barrel/pincushion distortion (not
uncommon in super-wide fixed focal length lenses but particularly common
in zooms) it is far better than the Vivitar, whose distortion must be
one of the worst of any modern lens.

The Tokina costs 20% more than the Vivitar. It is worth every penny.

There is also a much more expensive Tokina 20-35mm with an f/2.8
constant maximum aperture.  It's a good lens but isn't quite as sharp or
contrasty as its cheaper sibling.  However barrel/pincushion distortion
is kept very low and this means it is suitable for architectural
photography, which the cheaper Tokina is not.

I don't know anything about the Sigma lens you mentioned.  I've owned
six Sigmas at various times since 1975, and they have all been poorly
made and/or difficult or impossible to get repaired.  I recently had to
sell my last two Sigmas (a 70-210mm f/2.8 APO AF and a 24mm f/2.8 AF)
with the faults declared but unrepaired.

I will never buy another Sigma.  Who knows?  You might be more lucky.

I hope this is useful.

--
Tony Polson

I just returned my Sigma 24 2.8 to the dealer because it would not
register an aperture lower than 3.5 (in fact, it skip from 5.6 to 3.5).
I tried 2 other Sigma 24/2.8 and they all had the same problem on my
Pentax 5n body.  I called Sigma and they said it might be a compatibilty
problem and to send them the lens.  I tried other 2.8 lens with out a
problem, including Sigma.  The dealer tried the 24/2.8 on other Pentax
bodies/models and had the same problem.  Looks like Sigma didn't do
their homework while developing the mount for Pentax.