Sigma/Foveon Questions
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From: David J Taylor on 24 Apr 2010 09:11 "Alfred Molon" <alfred_molon(a)yahoo.com> wrote in message news:MPG.263cd4fe18b557af98c2ab(a)news.supernews.com... > In article <etloZZDEnj0LFwmT(a)kennedym.demon.co.uk>, Kennedy McEwen > says... >> The only assumption I am making is that the laws of physics apply to >> the >> Foveon device, and that determines the absorption depth of each colour >> in the silicon and also the QE of each colour. > > A few years ago, people (let's call them "experts") in this NG were > postulating that by the laws of physics sensors with live view would > have higher noise levels than sensors without. How wrong they were. > -- > > Alfred Molon I thought they were talking about implementation issues, not ones due to the laws of physics. Perhaps you would like to provide a citation? Many of today's sensors still have relatively poor QE, so there are still improvements to be had. David
From: Alfred Molon on 24 Apr 2010 14:40 In article <hquqp1$snm$1(a)news.eternal-september.org>, David J Taylor says... > I thought they were talking about implementation issues, not ones due to > the laws of physics. Perhaps you would like to provide a citation? They were explaining that because the light sensitive area would be reduced by the live view circuitry, noise levels would rise. You might want to google for these threads in the ng. In any case, unless you are somebody who is designing these sensors, you are not in a position to make qualified statements about what is possible and what is not. -- Alfred Molon ------------------------------ Olympus E-series DSLRs and micro 4/3 forum at http://tech.groups.yahoo.com/group/MyOlympus/ http://myolympus.org/ photo sharing site
From: David J Taylor on 24 Apr 2010 15:39 "Alfred Molon" <alfred_molon(a)yahoo.com> wrote in message news:MPG.263d59854702a97198c2ac(a)news.supernews.com... > In article <hquqp1$snm$1(a)news.eternal-september.org>, David J Taylor > says... >> I thought they were talking about implementation issues, not ones due >> to >> the laws of physics. Perhaps you would like to provide a citation? > > They were explaining that because the light sensitive area would be > reduced by the live view circuitry, noise levels would rise. You might > want to google for these threads in the ng. > > In any case, unless you are somebody who is designing these sensors, you > are not in a position to make qualified statements about what is > possible and what is not. > -- > > Alfred Molon If what you say is correct, Alfred, what they were saying is also correct, and in accordance with the physics of the situation. Less sensitive area captures fewer photons, which means more noise. Today, improved micro-lenses and higher QE may well have offset the reduced sensing area. A cite would still be welcome. David
From: nospam on 24 Apr 2010 18:59 In article <hqu821$1si$1(a)news.eternal-september.org>, David J Taylor <david-taylor(a)blueyonder.co.uk.invalid> wrote: > >> So how is the red and green content at the blue pixel location created, > >> if > >> not by spatial interpolation? > > > > it looks to its neighbors to calculate the missing components. it's not > > upsizing anything. > > "looking to its neighbours" /is/ spatial interpolation. however, the total number doesn't change. there are 12 million on the sensor and 12 million in the image, or however many the sensor has. > You could regard it as upsizing 1 million red sensor pixels to the red > component of a 4 million pixel RGB image, if that helps. except that bayer doesn't upsize each component and then combine them.
From: nospam on 24 Apr 2010 19:01
In article <hqvhdi$doo$1(a)news.eternal-september.org>, David J Taylor <david-taylor(a)blueyonder.co.uk.invalid> wrote: > > They were explaining that because the light sensitive area would be > > reduced by the live view circuitry, noise levels would rise. You might > > want to google for these threads in the ng. > > > > In any case, unless you are somebody who is designing these sensors, you > > are not in a position to make qualified statements about what is > > possible and what is not. > If what you say is correct, Alfred, what they were saying is also correct, > and in accordance with the physics of the situation. Less sensitive area > captures fewer photons, which means more noise. Today, improved > micro-lenses and higher QE may well have offset the reduced sensing area. people did say that live view would impact the noise levels, but the missing piece is that sensor technology advanced which offsets any loss. |