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Re: cameras used
Max Galladé wrote:
In response to my:
>> . Ignore the hype about having more pixels, unless you are certain
>> they can be used.
>
> Max answers:
> Huh?You're loosing me here.
> I quote "The number of pixels used to make up an image is directly
> proportional to the human eye's perception of image's sharpness.The more
> pixels there are the greater the level of detail captured in the whole
> image,and vice- versa fewer pixels=fewer details"
> Reference :Megapixel.net Article:Resolution and image sharpness.
That is not true. Perhaps you are overlooking some assumptions? The camera
marketing types are *eager* for you to do so, for the pixel race has sold a
*lot* of snapshot cameras.
Only if the *lens* can resolve details as small as a single pixel, is that
statement generally true. As soon as lens resolution (or focus, etc.)
provides details that are all larger than the pixel size, then you have
essentially "empty resolution." About 90% of the consumer digital cameras
have lenses that cannot possibly resolve to the capability of a 3 MP CCD.
If the tiniest image of a perfect point source is covering 20 pixels, then
another point source next to it, but displaced by only one pixel, will not
be resolved as a separate point. It's that simple.
The consumer cameras often use very poor lenses designed for low-res video
cameras, to get a huge zoom range. Folks don't seem to care.
I downloaded the USAF test chart from the web, and proved to myself that the
lenses were the real limit to resolution of several cameras I considered,
and the absolute number of CCD cells was unimportant. My Sony 770 has only
1.5 MP, but I can do 8X10 prints that cannot be told from film pictures,
with it. Internal algorithms and progressive scan make it the equal of all
but about 3 cameras with higher MP, and you don't want to pay for any of
them.
Wright
PS. I'm cheating. I've been an optical engineer for over 4 decades, now.
--
Wright Huntley, Fremont CA, USA, 510 494-8679 wright at killi dot net
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