Re: [APML] Re: (OT) IC1396 CCD with Schmidt-like FOV

["Robert Gendler" <robgendler@worldnet.att.net>]

Hi Philip,
Resolution in the context of image size is really a meaningless concept.
The ability of an image to hold up to enlargement and in particular printing
is much more than a function of actual pixel count. The overall smoothness
and
in particular the S/N is much more important. I know Tony will back me
up on this since he has done alot of printing for me. I have given him files
that were barely 6MB but were very well exposed with excellent S/N
and he has made quality 40 x 20" prints. CCD images if well exposed are
very smooth in quality and the actual detail in the image can be much
greater
than comparable film images scanned at much higher resolution. Loke even
pointed out that VDB142 in the CCD image had more detail than the film
image despite identical focal lengths and much smaller aperture for
the CCD image (8" vs 3"). Ultimately its not the pixel count but the amount
of real information recorded by the medium that counts.
Rob Gendler
Email: robgendler@att.net
Web site: http://www.robgendlerastropics.com/
> The detail and FOV may compare favourably at *web resolution* with a
medium
> format image.  But as you know (from your own excellent work with medium
> format) the medium format image has to be hugely downscaled for web
> resolution.  The raison d'etre for medium format (with you also I assume)
> is to produce large exhibition-quality prints while preserving the full
> integrity of the image (little or no upscaling).  By dowscaling for web
> resolution, the detail of a medium format image is compromised
> severely.  When comparing like for like, a full resolution medium format
> image (when scanned on your UMAX or equivalent) will yield a resolution of
> around 8,100 x 6,900 pixels.  I am not sure that an ST-10 image at 2,184 x
> 1,472 pixels "compares favourably".  Much more detail will be apparent in
> the full resolution medium format image. The ST-10 image has nearly 18
> times less area.  And that is only the resolution aspect - in terms of
> field coverage the difference is even more stark.
>
> --Philip
>
> Philip Perkins - philip@astrocruise.com
> Wiltshire UK & Luberon France
> Astrocruise - http://www.astrocruise.com
>
>
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