F. Craig Callahan & Thys wrote (edited):
Thys wrote:
> > Also, Photodo doesn't seem to have bias towards IS or non-IS lenses,
> > while it is obvious that Canon earns money on non-IS to IS upgrades.
>
> Yes, I realize they are calculated, but sorry, I don't buy that they would
> fabricate graphs just to improve their sales.
Fabricate as in "falsify": perhaps not. But they *are* fabricated in the
sense
that they're generated from the design specifications rather than by actual
testing.
> How many lenses did photodo test?
In fairness, they probably tested one--which is one more than Canon used to
get
its MTF graphs. :-)
> (How scientifically accurate is it really?)
Pretty accurate, it would seem. Certainly no less accurate than Canon's
computer-generated results. Also, Photodo results seem generally consistent
with
those obtained by Chasseur d'Images (and there's a description, with photos,
of
CdI's testing procedure in the current issue).
_______________________________________________________________________
As with all magazines, or sites such as Photodo, testers are only given
ONE sample lens to test. This goes for Pop Photo, CDI, et al.
While the 300 F4 non-IS may be tested sharper the IS lens clearly
has the advantage handheld. In this case the results are sharper
than your trying to handhold the non-IS lens. The other possiblility
is that the 300mm F4 IS L test sample may not have been as good
as sunsequent models. Example, Pop Photo and Photodo concur
the Tamron 20-40mm is super sharp, yet CDI says quite the
opposite almost as if they were testing a different lens.
Either way, note that at F8 there is only a 5% tested difference
in sharpness between the two. This can be overcome with
good exposure, good film with IS adding to both.
I would put money that FCC owns the 300mm F4 non-IS lens.
Peter K
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