From: axman@acadia.Kodak.COM (Mike Axman)
Subject: Re: Re: Digital Photography
Organization: Eastman Kodak Co., Rochester, NY
Date: Mon, 14 Sep 92 12:30:49 GMT

In article <1992Sep11.150459.22412@skylinx.sa.com>, rob@skylinx.sa.com (Rob Cartaino) writes:
>axman@acadia.Kodak.COM (Mike Axman) writes:
>> 
>> In article <72219@apple.Apple.COM>, bc@Apple.COM (bill coderre) writes:
>>>In article <PD.92Sep9020725@horus.sics.se> pd@sics.se (Per Danielsson) writes:
>>>|Digital photography (as in digital cameras) is still very expensive.
>>>|My guess is that it will take many years until it will become
>>>|affordable by amateur photographers.
>>>
>>>You can buy a Canon still video camera with a Mac interface for about
>>>$900. Yup, that's too expensive for the average Joe, but I have used
>>>one to take instant photos for desktop publishing, and it works better
>>>than you might think.
>>>
>> 
>> The caveat here is the "desktop publishing" slant as opposed to "digital 
>> photography".  I've used quite a few of these beasts as well, including the 
>> Toshiba "all digital" version, and they are great for incorporating in 
>> documents, etc...
>> 
>> Most people in this forum would not be happy with this quality in a 
>> "digital photography" mode, however; even on the TV screen.  
>
>If you are interrested photographs solely for the purpose viewing
>them on a computer screen (i.e. .GIF format) which method will produce
>a better quality output:
>
>	1. taking a 35mm photograph and scanning it with a color scanner or
>
>	2. taking the photograph with one of these digital cameras?
>

Well, let me take a shot at this one.  At first glance, you would think 
that taking the image directly with a digital camera would involve less 
"transfer functions" and result in higher quality.  When the technology 
matures, this might be the case.  With today's devices, however, method #1
has a number of important advantages:

	a)  Highest resolution.  Most digital cameras employ an "area array" 
	CCD sensor, whereas scanners are typically "linear arrays".
	For obvious reasons, making a 2kx2k (or whatever) AREA array involves
	must higher cost/difficulty than making a 2kxN LINEAR array.
	For this reason, among others, you won't find many CCD-based digital
	cameras available at anything close to the resolution of lots and lots
	of commercially available scanners.

	b)  More Control.  In a scanning situation, you can very tightly 
	control the illumination, focus, etc... to capture the best data.
	This issue is closely linked with the fact the conventional films
	are much better image capture devices than CCD arrays.  CCDs have 
	limited dynamic range and are therefore more dependent on accurate 
	exposure control.  CCDs are higher noise (at equivalent "speed") 
	in area array cameras, resulting in a worse speed/grain tradeoff
	when compared to photographic film.  Film, especially negatives, 
	are just generally more suited to initial image capture.

   


>Also, assuming the resolutions your are trying to achieve 
>are for IBM-compatable VGA/SVGA monitors 
>(640x480, 800x600, 1024x768, and maybe 1280x1024) which digital
>cameras can handle these resolution without being overkill?
>
 
Not many.  The Kodak CCD back for the Nikon is in this league, but fairly
expensive.  Toshiba has an all-digital at about 640x480, but it was over 
$15K last time I checked.
Let me also say that all of these issues are "moving targets", as CCD 
technology improves.  Working here at Kodak, I have access to all of the 
latest electronic cameras and devices, but I shoot film for "insurance".
Insurance of exposure and zoomability.  When I want to manipulate or 
display the image, I then scan it.  

I am basically a 35mm kinda guy.  If you are accustomed to the quality of 
medium or large format film, don't even think about digital capture :-)

mike

>
>
>-- 
>---                                              
>Rob Cartaino - Melbourne, FL
>rob@skylinx.sa.com

-- 
Mike Axman  
CD-Imaging Advanced Development
Eastman Kodak Company
axman@acadia.kodak.com



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