OT: Re: VCF Suggestions (film vs. digital cameras)

On Mon, 8 Aug 2005 14:53:20 -0400 "Barry Watzman" <Watzman at neo.rr.com> wrote: http://www.kenrockwell.com/tech/mpmyth.htm "I find that it takes about 25 megapixels to simulate 35mm film" 6 "true" color megapixels are 24 "false" megapixels. The megapixel count the manufacturers print in their ads actually is the count of the "false" (i.e. bayer sub-) pixels. Based on those subpixels you can interpolate one "false" color pixel per bayer subpixel. Obviously interpolated pixels are not real color pixels so you get interpolation artifacts like moire effects... A bayer pixel is formed like this: R G G B i.e. four subpixels per color pixel. Two subpixels are green, one red and one blue. There are two green subpixels because the human eye is very sentive for green shades. Based on this the camera interpolates one "false" color pixel for each subpixel. Therefore the count of real color pixels is one quater of the number the manufacturer prints on the box... This is obviously not true for cameras with three CCD / CMOS image sensors. There you get only "real" color pixels, no interpolation required. But: Is there any DSLR with three CCD / CMOS sensors? Lets do some math: An A4 paper is about 8" to 12". The minimum resolution a print requires to hide the pixel structure is 300 dpi. (This is not good, it is the minimum!) 300 dpi gives 90000, say 100000 pixels per square inch. The print is about 8" * 12" = 96 square inch, say 100 square inch. So you get 100000 pixels per square inch * 100 square inch = 10 megapixel. True pixels, not interpolated bayer subpixels. I.e. you will need a 40 megapixel camera to get this. OK, you may get away with the interpolated pixels, so a 10 megapixel DSLR can do this job. Not to talk about color depth... (e.g. digicams use RGB, i.e. additive, printers CMYK, i.e. subtractive color models. Conversion frome one to the other is lossy.) Or think about a slide show. How much does a digital projector cost that can project your 10 megapixel digital images at full resolution? Good, old, analog slides will get you there much cheaper. You may get away with even less then 10 megapixels depending on the subject, how good the interpolation works and most important how high your demand for quality is. Still, for real fine art, e.g. architecture, photography and large prints, e.g. 30 cm * 40 cm and above, a large format camera is the way to go. Period. -- tsch??, Jochen Homepage: http://www.unixag-kl.fh-kl.de/~jkunz/