Sigma/Foveon Questions
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From: nospam on 21 Apr 2010 00:15 In article <4bce6e6e$0$1601$742ec2ed(a)news.sonic.net>, Ray Fischer <rfischer(a)sonic.net> wrote: > >> you may not capture full luminance but you do capture enough > >> information to calculate the correct value. the system works. > > > >Bayer does not capture the luminance at the pixel level, period. > > And yet there are billions of photos captured with Bayer sensors that > have luminance information in them. > > Go figure. they're *really* good guesses :)
From: nospam on 21 Apr 2010 00:20 In article <Nafc0rFzYlzLFweW(a)kennedym.demon.co.uk>, Kennedy McEwen <rkm(a)nospam.demon.co.uk> wrote: > Given the same pixel density Foveon tech *can* have higher resolution > than Bayer. That is a no-brainer. a little. the main difference is no anti-alias filter, not the sensor technology. > However the reason it doesn't is > *because* only Sigma are supporting it, and the fuckwits using the > existing comparison argument only re-inforce that. With 1% of the > money, who is surprised that Sigma are 5 years behind the resolution > curve? try ten years. the 4 mp canon 1d came out in 2001. sigma is *still* at 4.6 megapixels, some 9 years later. > Don't obscure cause and effect. > - and don't obscure human eye limitations with image limitations - you > can print at any size, even those where the human retina doesn't limit > resolved perception. large prints are viewed from farther away. it's not like someone is going to take a loupe to a billboard.
From: jgh on 22 Apr 2010 18:10 On Thu, 22 Apr 2010 07:48:15 +0100, Martin Brown wrote: > You really do need to post an *example* of this mythical "red flare" you > keep harping on about. I've seen an example posted. Somewhere. Maybe not in r.p.d though. Subject was a welder in action (probably arc). Around the highlight (and I could believe it was *very* bright, as the rest of the image was exposed nominally) there was a square grid of red blobs overlaying the scene, fading out away from the highlight. There would have been on order of twenty blobs over the height of the whole image, had they not faded. I wondered if the effect was a double reflection, from the sensor surface then from a lens element surface. - Jeremy
From: Ray Fischer on 22 Apr 2010 00:41 Kennedy McEwen <rkm(a)kennedym.demon.co.uk> wrote: >In article <210420101542128471%nospam(a)nospam.invalid>, nospam ><nospam(a)nospam.invalid> writes >>In article >><cd4821ed-e063-472e-b52f-2ca5bf5fd206(a)k33g2000yqc.googlegroups.com>, >>Bubba <digitalrube(a)yahoo.com> wrote: >> >>> > You didn't know that Bayer sensors have twice as many green pixels? >>> >>> No. That's why I post questions here. Why in God's name would they >>> have twice as many? >> >>because there are three primary colours that need to fit into a 2x2 >>grid. > >Nothing of the sort. There is no requirement for a 2x2 grid, the >colours could be arranged as triads, as in the dots on a conventional >colour CRT, or as linear triplets as in the lines of a Trinitron screen >or LCD & Plasma displays. They would be expensive and would reduce the number of total pixels. It would also require interpolation to translate to the ubiquitous retangular grid of displays and file formats. -- Ray Fischer rfischer(a)sonic.net
From: Alfred Molon on 22 Apr 2010 02:16
In article <F3UOP1Ccn5zLFw9P(a)kennedym.demon.co.uk>, Kennedy McEwen says... > Mismatched spectral response is one of the reasons why the Foveon > concept isn't as good as its supporters claim. Whilst you do get full > colour pixels, and hence increased resolution over a similar pixel count > BFA camera, the response is a poor match to the eye. Foveon's highest > response is to blue, then green and then red. If so, wouldn't it be sufficient to multiply the blue channel by a factor < 1.0? Or are you claiming that cameras with a prism and three separate sensors (R, G and B), are a bad solution because they do not match the human eye's sensitivity? -- Alfred Molon ------------------------------ Olympus E-series DSLRs and micro 4/3 forum at http://tech.groups.yahoo.com/group/MyOlympus/ http://myolympus.org/ photo sharing site |