Rockwell on DSLR vs. P&S

External Since: Sep 07, 2006 Posts: 291

In rec.photo.digital AAvK <Idondodat.DeleteThis@wahoo.com> wrote:

>>> I would like to know, what are the better downsamplers?
>>
>> At whole-fraction scaling factors (25%, 33%, 50%, 67%, 75%)
>> most downsampling algorithms give identical results.
>> Otherwise Lanczos is far better than Bicubic for most images.
>> Lanczos leaves smooth areas smooth and keeps edges sharp.
>>
> OK thanks for the reply! I guess the closest I've got to Lanczos
> is Irfanview and xnview. But I've read that Irfanview's version
> is not the whole version that is installed in a software program,
> PhotoLine32 has it full versioned, written in Germany.

Are you implying that the same guy (Irfan Skiljan) is responsible
for both Irfanview and PhotoLine32? I did not know that.

The Lanczos filter in Irfanview works great, as does the one in
ImageMagick's "convert" program. I don't know xnview. I believe
the Lanczos algorithm is fairly standard in graphics textbooks.

External Since: Jun 01, 2007 Posts: 181

On Oct 6, 2:42 am, "David Ruether" <r....RemoveThis@no-junk.cornell.edu> wrote:
> "David Ruether" <r....RemoveThis@no-junk.cornell.edu> wrote in messagenews:fe3s9v$rk5$1@ruby.cit.cornell.edu...
> >> I should have this up in an hour or so, but I will put up comparison
> >> photos atwww.doughicksphotography.com/comparison.htm.
> >> of a D1x with an 18-70mm at 18mm and f4 and a Sony 707 at
> >> 10mm and f4.5 (about the same angle of view). The files will be
> >> very large...
> >> --
> >> David Ruether
>
> YIKES!!! I had no idea that this would result in so much, uh,
> conversation...! 8^)

Hah, as if you haven't been posting on usenet for years. Any
comparison will be claimed by half the people replying to prove their
point beyond doubt, and by the other half to prove the opposite point,
also beyond doubt Smile

> BTW, I agree with most of the comments,
> both negative and positive (and I had noted that the Sony 707
> unfortunately did have its sharpening raised a notch - and the
> excessive ringing is a major problem when shooting some types
> of photos, but for many types, it isn't [see 80 photos shot with
> it,www.donferrario.com/ruether/digital-photos1.htm]).

Yes, also the ringing artifacts can be reduced by reducing the
sharpening settings in the camera, if they are undesirable. And the
excessive chromatic aberration in the sony image can be reduced by
software if necessary. Regarding the colour differences, these are
basically a matter of taste (I don't like the sony image, but others
might); and anyway shooting raw gives more choice in that (either in
the raw converter, or through a choice of raw converter).

But I found some people's reactions quite amusing, especially in view
of other posts they've made in the past...

Anyway, in conditions like those your shots were taken under (ie
higher sensitivities not necessary), I don't think there is much
difference in practical results for eg A4 size or so (and maybe more,
I haven't tried with a point and shoot-but they have higher noise, and
this does limit your ability to play with the image afterwards, if
you're into that).

> I've
> used cameras in all formats from 110 to 8x10 and this digital
> 707 has been the most fun - and with its *f2-2.6* 35-180mm
> equivalent lens (extended to 28mm with a suitable converter),
> images are sharp everywhere in the frame even wide open, and
> sufficiently good for satisfying 8x10 prints *so long as skies
> are not cut by strongly contrasting subject parts*. As always,
> there are no perfect choices in cameras (except perhaps for
> *very* particular applications) - but there can be several good
> compromise choices that cover a variety of applications.
> Shoot with whatever "floats your boat..." 8^)

An excellent point!