Just a few comments on your follow up:
On the other hand I believe the lens "only" performs - say 90-95% -
of the performance of the AF-S 17-35/2.8 - which is an excellent
piece of optic. Being a bit critical, the performance of the lens
lacks a bit of sharpness and what I would best describe as
brilliance (or the ability to shine). The difference is IOW not
huge, but slightly present.
Hm ... I cannot confirm this. Both of these lenses are very sharp
on my D1x and I also have primes to compare. It's not as sharp as
the 60mm Micro of course. But both AF-S zooms you mentioned are for
me on the same quality standard.
Have you made a comparison of both lenses in the same range?
I have not made any scientific comparison, however I do have
compared different pictures (done with my F5 - have not yet bought
a digital camera) shot at identical ranges. Based on that general
experience, yes I do find a minor difference (particular) in terms
of brilliance.
Just to mention a few reviews which I believe supports the above
mentioned "tiny difference" between the Nikkor AF-S 28-70/2.8 and
it's equivalents i terms of optical quality:
Michael Weber's comments on the lens:
"When it comes to optical quality I was slightly disappointed by
Nikon. Compared to a Canon EF 28-70/2.8 ... the AF-S is an
underperformer".
Source:
http://www.imagepower.de/IMAGES/imgEQUIPMENT/AFS2870.htm
Photodo has rated the following lenses:
Nikon AF-S 28-70/2.8 - 3.7
Canon EF 28-70/2.8 - 3.9
Nikon AF-S 80-200/2.8 - 4.1
Canon EF 70-200/2.8 - 4.1
(BTW, the Nikkor 50/1.4 is rated at 4.2 & Nikkor 60/2.8 likewise at
4.2)
Source:
http://www.photodo.com/nav/prodindex.html
Photodo has not done any tests lately, and has not done any test on
the Nikkor AF-S 17-35/2.8 nor the Nikkor AF-S 70-200/2.8. But
comparing the Nikkor 28-70/2.8 to the three others (or five others)
is nevertheless a bit disappointing. I know these data might raise
the issue of test reliability - that tests possess a certain degree
of measurement error?
Finally, has Ron Reznick at his homepage reviewed both the AF-S
17-35/2.8 and the AF-S 28-70/2.8 in the following terminology:
Ron Reznick describes the AF-S 28-70/2.8 as the "... class act if
what you are looking for is single-lens flexibility in the
medium-wide to short-tele range ...", but regarding the optical
quality Ron states that "... the quality of the shot acquired is
well under the quality you get from a prime ...".
A slightly different review regards the AF-S 17-35/2.8; as stated
by Ron:
"... this lens is equal to or better than the primes it is intended
to replace within this aperture range. I use the primes when
shooting wide apertures (or the 45/P by itself when having a
lightweight, general-purpose lens makes sense), but for travel and
many other situations where flexibility of focal length is of
critical importance, this lens is invaluable".
Source:
http://www.digital-images.net/Lenses/lenses.html
The only complain I have that the 28-70 can flare even with the
lens hood mounted.
I have not (yet) experienced any flare with my Nikkor 28-70/2.8,
but I know that Ron - at his homepage - also notes that the lens
tends to flare if shooting towards the sun.
I do find the AF-S 28-70/2.8 a superb zoom lens, but do at the same
time recognize a minor or slightly difference compared to e.g. the
AF-S 17-35 or my 50/1.4 not to forget the 60/2.8 micro. Different
evaluations of the lenses is always a good reason for starting a
dialogue - Bjørn Rørslett has for instance rated the Nikkor
28-70/2.8 very high (5 out of 5)?
I have not wished to offend any AF-S 28-70 lenses nor their owners,
but only to comment that this is indeed a great lens - perhaps only
95% as great as some of the other lenses in terms of optical
quality.
-- Klaus Bergstedt --