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could a BW only digital camera be effective?


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Perhaps a dumb idea, but following from a thread about shooting bw in

current digicams, would there be any technical advantage in

developing a BW only digicam. Could it provide greater resolution at

less cost?

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B&W bitmap and greyscale cameras and scanners are standard in industrial applications; such as the scanning of Engineering drawings; scanning/photographing of checks and documents. Many times the color info is not required; and the resulting file size is only one third in size; for a given pixel level; comparing grayscale to RGB. Some industrial scanners also maybe at lower than 8 bits; say 4 to 6 bits of info for greyscale; in older scanners/sensors. (this helps still read a document; with writing too light; which will be lost with a straight bitmap image; where every pixel is either white or black. Greyscale B&W sensors vary in their color accuracy; some types are blind to blue on white; some to yellows on white also.
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interesting point Chip.



the market evolves...when I started out, BW film was cheaper to lab process and print then colour film (at least I remember it that way) and if I remember correctly the cost per shot was cheaper if you shot Kodachrome (but then you had to pay more for an enlargement print). Now BW lab process and print costs a small fortune. C41 processing machines and volume work I realize are part of that change.


Still people seem to respond and enjoy BW images.


And 100 ASA colour print film is more expensive than 200 or 400 at smaller retail outlets or is not even available (Walmart where they start out at 200 Fuji, at least here in Canada).


So it will be interesting to see how this digital market evolves. The cell phone cameras seem nuts to me but what do I know.

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<I>Same resolution, but a nice tripling in sensitivity with no noise increase due to the missing bayer mask.</I><P>


No, it would also be higher resolution. Imagine you were shooting a test pattern that was simply blue. Some of the detail would fall on the R and G filters of the bayer bask and not be detected. Bayer-pattern sensors are simply making their <B>BEST GUESS</B> of what the image consisted of. There is no separate LUMINANCE channel to go with the CHROMA channel.<P>


A BW-only camera would be WONDERFUL but there's no market for it.

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Fuji has a black & white setting built into it's s1 and s2. it produces basically a

desaturated rgb file but it prints better on a frontier printer I think there is a touch of

magenta in it although I can't see it in the histograms. It is a very usefull feature

when previewing images. would a b&w preview for a color pic be as good as a color

preview. Sometimes though with skill, patience and experience a translation from a

color file is better. Some of the tricks filters do can help in color balnce and levels

before going b&w.

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"No, it would also be higher resolution."


No, it would be the same resolution. Bayer cameras resolve about 70% of their Nyquist frequency, and that would be about the limit for a B&W sensor as well. Why? Because to correctly sample the image, you must use an antialiasing filter (since aliasing artifacts are indistinguishable from real data after the fact). And that means that the best you can do is about 70% of Nyquist. Sigh.


A B&W camera would have the extra sensitivity. It would also have the advantage that it wouldn't lose 3/4 of its resolution when you put a red filter in front of the lens, so it would be much better for B&W landscapes.

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