[Gllug] How crap is that digital camera in the window?

[Rev Simon Rumble]

I meant to mention this in the earlier thread.  This is a quick way to
see how good or bad a digital camera is.  One of the big problems with
cheap CCDs and interpolated "resolution" enhancements is noise in the
blue channel.  So a good way to see how good an individual camera is
will be to check the blue channel.

Take a photo and download it to the computer in a non-lossy
compression format (i.e., not JPEG: if it can't do that it's already a
crap camera and should be avoided unless it costs less than fifty quid
and you don't have high expectations).  Open it up in GIMP, Photoshop,
Paint Shop Pro or other image editting application which has a
"Channels" palette or similar feature.

Now open the Channels palette and have a look at the Blue channel.  In
PSP, use the "Channel Splitting" thing.

Now compare it with photos taken by other digicams, preferably with a
really high-end one thrown in for good measure.  A good digicam will
have little noise and distortion on this Channel.  A bad one will be
REALLY noisy.

I remember learning the physics of this but I can't remember now.

On a related note, a quick and dirty way to make crap digicam images
look a little better is run an Unsharp Mask filter JUST on the blue
channel.

-- 
Rev Simon Rumble <simon at rumble.net>
www.rumble.net
Send email with subject "send key pub" for public key.

Hockey is a sport for white men.
Basketball is a sport for black men.
Golf is a sport for white men dressed like black pimps.

- Tiger Woods
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