Re: time to get digital camera?

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There is a pitfall in looking at the megapixel rating of digital cameras 
that needs to be considered when comparing them to scanned "film" images.

All digital camera manufacturers seem to have agreed to use a convention 
in determining the resolution of their sensors, which, as long as you 
are comparing them to one another within the digital camera realm, will 
work.  What I mean by this is that a 4 megapixel camera sensor does 
indeed have 2 times the number of data point to that of a 2 megapixel one.

However, a 4 megapixel digital camera image does not have the same 
information as a 4 megapixel color scanned image.  The reason for this 
is that when a digital camera sensor resolution is measured, a count is 
made of all the sensor elements across multiplied by how many down. 
This does indeed tell you how many individual sensors there are, BUT, 
and this is a "big but", unlike with a scanned image, where each sensor 
element takes a red, green and blue reading and combines them to make a 
24 bit (or whatever) color data point, the digital camera sensors, are 
each covered with a red, green OR blue "lens/filter", so that sensor is 
only able to measure the color content of one of those colors.

Therefore, to get a full color data point 3 or 4 sensor elements are 
needed to make one complete color information point.  As a result, you 
can pretty much divide the megapixel number by 3 or 4 to get closer to 
the real resolution of the image in full color.

So, you really can't use direct dpi numbers from the megapixel rating to 
determine how large you can print on an inkjet printer.

Art

Harry Minoru Shin wrote:

> Hi:
> 1.  I'm wondering if it's getting time to finally get a digital camera;
> specifically I'm interested in the upcoming Contax N Digital etc... 
> 
> 2.  Question:  How do I calculate maximum print size based on the variables
> of megapixel amount (camera) and printer (dpi--ex: 300)?   Pragmatically,
> I'm wondering what size print I can get out of these 6 megapixel cameras.
>   
> 3.  Thanks for the info--I figure some folks in the scanning community
> are wondering when they should buy digital cameras etc...
> 
> 
> Harry Shin
> 
>              For as long as space endures,
>      And for as long as living beings remain, 
>                 Until then may I, too, abide
>            To dispel the misery of the world.  
> 
>                            The Dalai Lama
> 
> 
> 
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