Re: D2Xs versus D200 etc.

ASAAR <caught@xxxxxx> wrote:
On Sat, 09 Jun 2007 15:28:20 -0800, Floyd, L'Argumenterrier Davidson
wrote:

This would allow, for example, some
foolish 'arguers' (and we know who they might be) to claim that a
cheap $200 telephoto zoom produces higher quality images than a
$2000 zoom of comparable focal length, because the cheap one can
focus as close as 10 feet while the expensive lens with far better
glass can focus no closer than 25 feet.

The close focusing distance of a lense *is* an important
feature. We might note however that closer focusing is
more expensive to design and build, hence your argument
is reversed from reality. The $2000 lense would focus
at 10 feet, while the $200 lense would be more limited.

Of course it is, but you must take pride in being dens(sic), since
focusing distance is not measured in units of image quality.

Your imagination for insults is far greater than you
ability to understand technical points.

In fact, almost universally the limit on close focus is
a design decision based on image quality, which would
degenerate if the mechanical limit was not imposed.
More expensive designs are required for closer focusing
if quality to be maintained. Telephoto lenses at $2000
compared to $200 are almost certainly going to have 1)
vastly superior sharpness, and 2) equal or closer
focusing.

Expensive, high quality lenses achieve their quality by not being
designed to cover extreme focusing ranges.

For equal quality, closer focusing *will* cause a higher
price. El cheapo lenses achieve their low cost by
restricting the focusing ranges.

A clue: think of why
there are macro lenses.

Clue:

Macro lenses typically are not as sharp at infinity as
regular lenses; generally because macro lenses trade
field flatness for astigmatism, which can be
accomplished only over a relatively narrow focusing
range.

Cheaper lenses, designed for those P&S
owners impressed by multi-mega pixel sensors can have wider ranges,
because image quality isn't paramount. My own P&S can focus down to
about 2 feet at its 380mm (equiv.) focal length and when zoomed
wider, down to a couple of inches. Many other P&S zooms focus down
to a couple of cm.

Oh. You use a P&S with cheap lenses and have no idea what
you are talking about. That figures.

Don't try to compare telephotos with coverage for 35mm
format with telephotos for P&S cameras with small
sensors. You'll confuse cause and effect.

Do the high quality zooms (up to 400mm f.l.)
costing several thousands of dollars focus as closely? Or will you

Yes.

Of course you can't find any such lenses mounted on the
cheap P&S cameras you use, so you aren't aware of that.

You've misunderstood the significance of the lense
either not requiring high resolution and/or having a
very small area of coverage.

try to find some agument loophole that will allow you to argue about
something else?

You have no technically valid points, so it's time for
the usual insults to begin.

--
Floyd L. Davidson <http://www.apaflo.com/floyd_davidson>
Ukpeagvik (Barrow, Alaska) floyd@xxxxxxxxxx
.

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