Hi,
I divide geometrical distortions to good and bad not by percentage, but
how even it is. If the distortion is even, resulting arches can be
easily transformed back to straight lines. I have analyzed several
wide-angle zooms and many of 'em bend straight lines to complex curves
that are nearly impossible to "straighten". Those lenses often measure
quite OK (i.e. distortion result as percentage in Imatest is rather
low), but there's no software that could effectively correct the image.
Pentax DA* 16-50mm distorts quite "good", especially at wide end.
BR, Margus
JC OConnell wrote:
I would say it depends on what you mostly use it for,
The geometric distortion would be very bad/annoying for
Horizons and anything else that is supposed to
Be straight, like buildings. Of course you
Could correct in a photoshop add-on for occasional
Usage like that, but if you used it all day
For linear things that's a pain in the arse
To have to do photoshop corrections...
JC O'Connell
[EMAIL PROTECTED]
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of
[EMAIL PROTECTED]
Sent: Sunday, November 09, 2008 2:37 PM
To: Pentax-Discuss Mail List
Subject: Re: DA* 16-50 review at photozone
Then you'l be missing out on a very fine lens. Certainly one of the best
zooms Pentax has ever produced. And I'd be surprised if it's not a lot
better than the 17-70. Paul
-------------- Original message ----------------------
From: Boris Liberman <[EMAIL PROTECTED]>
Let's just say that either measured or shown by example, the
distortion
at wide end makes this lens a no-go for me.
Boris
Subash wrote:
http://www.photozone.de/pentax/405-pentax_1650_28
<quote>
Verdict
It is difficult to find a final verdict for the Pentax SMC DA*
16-50mm f/2.8 ED [IF] SDM. On the one hand it has some obvious
problems like a weak border performance at max. aperture and very
pronounced lateral chromatic aberrations (CAs). On the other hand it
is really very sharp and contrasty at medium aperture settings
(f/5.6-8) and many users may actually forgive the border problems at
f/2.8 because you either stop down for conventional photography or
rely on the (very sharp) center for shallow depth-of-field
situations (e.g. portraits) anyway. The build quality of the lens is
also a step up from the consumer grade Pentax lenses and the silent
(although not overly speedy) SDM is an extra bonus on top. The
pricing of the Pentax 16-50mm f/2.8 is fair relative to its
performance and build quality.
</quote>
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