J. Clarke wrote:
Andrew Haley wrote:

Stacey wrote:
bmoag wrote:

[barrel distortion] can be reasonably corrected with some simple
image processing in the brave new digital world.

But doing this causes a loss of image quality and sharpness so it
still is a problem.

Well, that depends. You have to do raw conversion anyway, so you can
do the distortion correction at the same time, at high resolution.
Will this lose quality over not doing any geometric correction at all?
A little, but will it be visible?

Will the distortion be visible?

Yes.

In the end it's all about cost and weight. Is it cheaper to make a
sharp zoom lens with some barrel distortion than one without? And
is the resulting digitally corrected lens quality better value for
money (and weight) than one without any digital correction?

I suspect that if you have, say, $500 to spend on a lens, you're
going to get better quality by a combination of lens design and
digital correction than the best lens design can possibly do in its
own.

I can't see where digital correction is going to improve noticeably
on the less than 0.01 percent distortion of the $259 50mm Sigma
macro.

I think there has been a loss of context here. We're talking about
midrange zoom lenses, as the subject line suggests.

Further, most zooms have a sweet spot with very low distortion, the
trick is finding it and using it if low distortion is needed for a
particular shot.

As long as that's the focal length you need.

Andrew.