From: divenuts (divenuts_at_antispamdomain.not)
Date: Thu Nov 27 2003 - 18:37:23 EST
The results are interesting. I was actually doing the auto-focus when I
first started doing astrophoto(for the lack of knowing better), I had good
results, but after reading what the more experienced folks were doing, I
changed. Sometimes automation does work.
Chuck
----- Original Message -----
From: "jasuro" <jasuro_.at._attglobal.net>
To: <digital_astro_.at._yahoogroups.com>
Sent: Thursday, November 27, 2003 1:44 PM
Subject: [digital_astro] Re: Joanne's digital zoom theory seems to be
correct.
> Hi JoAnne,
>
> You're right about the digizoom - it's specified at 3.5x but I think
> they round. As for the digizoom image looking sharper I think it
> could be that the autofocus is more accurate at the digizoom
> setting - interesting in itself. Or it could be the JPEG algorithm.
> I did take a total of 17 images in the various settings and the
> results are all identical to the ones posted. The important thing is
> that it's not a bit less sharp - just as you predicted :). I did use
> autofocus for the test and did use a tripod/timer as well so it's
> not camera shake.
>
> All this has now got me thinking that with such a large image scale
> I might give the autofocus a try at the telescope. So far I've been
> focusing sans camera at the eyepiece and then connecting the camera
> set at infinity. It's worked pretty well but autofocus could be
> better if the infinity setting is just a bit off.
>
> More tests to follow soon. Thanks for suggesting this setup -
> definitely worth a try.
>
> Take Care,
>
> Jose Suro
> Tierra Verde, Florida
> http://web.tampabay.rr.com/jsuro/
>
>
> --- In digital_astro_.at._yahoogroups.com, "EarlyBird" <iamafink_.at._y...>
> wrote:
> > Hi Jose:
> >
> > Thanks for running the test. I take it you have something like
> 3.6x
> > digital zoom (rather than 3.2 like the A70)? Your higher
> resolution
> > would need a higher digital zoom to smoothly fit into 640x480.
> >
> > I'm very surprised that the digizoomed pic looks sharper, but it
> > certainly does. My theory was that it should be exactly the same,
> > just a smaller data size. I can't come up with an explanation for
> why
> > it would be sharper. Perhaps some more testing will show that this
> > was just a one-time coincidence?
> >
> > - JoAnne
> >
> > --- In digital_astro_.at._yahoogroups.com, "jasuro" <jasuro_.at._a...> wrote:
> > > Hi all,
> > >
> > > Waiting on the turkey today and decided to finally run some
> tests to
> > > check out Joanne's digital zoom theory. She seems to be correct.
> I
> > > ran a test shooting a barcode label at the full resolution of
> the
> > > camera and maximum optical zoom and then cropped the image to
> > > 640x480. This is how I shoot my planet pictures.
> > >
> > > I then shot the same barcode label using 640x480 resolution at
> full
> > > digital zoom. This image is definitely sharper. In addtion the
> time
> > > it takes to shoot a sequence of pictures in burst mode is
> > > signigicantly reduced allowing for more pictures in a specific
> time
> > > sequence. The file size difference was significant as well - 1.6
> > > megabytes for the full resolution image vs. 168k for the one at
> > > 640x480.
> > >
> > > The pictures are here:
> > >
> > > http://web.tampabay.rr.com/jsuro/digizoom_test.htm
> > >
> > > I will try it on the planets tonight or Saturday - depending on
> how
> > > much turkey I eat.
> > >
> > > Take Care,
> > >
> > > Jose Suro
> > > Tierra Verde, Florida
> > > http://web.tampabay.rr.com/jsuro/
>
>
>
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