Why only 4.6MP?
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From: Ray Fischer on 28 Feb 2010 18:12 nospam <nospam(a)nospam.invalid> wrote: > Alfred Molon <alfred_molon(a)yahoo.com> wrote: >> A 10MP full colour camera would be competitive - at least for what >> concerns the resolution - with the current crop of 12-15MP DSLRs. > >maybe, but a 10 mp full colour camera does not exist. Actually, Hasselblad annouced a new medium-format camera that can do full-color images by shifting a Bayer-sensor one by pixel for each of three exposures. It is, of course, not cheap and not suited to moving scenes. -- Ray Fischer rfischer(a)sonic.net
From: nospam on 28 Feb 2010 18:16 In article <4b8af84d$0$1617$742ec2ed(a)news.sonic.net>, Ray Fischer <rfischer(a)sonic.net> wrote: > Actually, Hasselblad annouced a new medium-format camera that can do > full-color images by shifting a Bayer-sensor one by pixel for each of > three exposures. it's basically a variant on taking 3 exposures and combining them later. > It is, of course, not cheap and not suited to moving scenes. right.
From: David J Taylor on 1 Mar 2010 01:32 "Alfred Molon" <alfred_molon(a)yahoo.com> wrote in message news:MPG.25f4dc1d2b7a4fab98c23c(a)news.supernews.com... > In article <hmdjf1$g7l$1(a)news.eternal-september.org>, david- > taylor(a)blueyonder.co.uk.invalid says... >> I suggested comparing today's cameras >> of similar effective resolution (citing a 4.6MP Foveon and 12MP Bayer >> as >> such cameras) > > 4.6Mp is not a "similar effective" resolution as a 12MP. A 4.6MP full > colour camera has a similar effective resolution of a 7MP bayer camera > (rough guesstimate, which obviously depends on the scene photographed). > But comparing a 4.6MP (full colour) camera with a 12MP bayer camera does > not make much sense. > > A 10MP full colour camera would be competitive - at least for what > concerns the resolution - with the current crop of 12-15MP DSLRs. It > would have larger pixels, far fewer aliasing problems and not put such > high demands on the optical resolution of the lens and diffraction would > be less of a problem, meaning that you could use smaller apertures. > -- > > Alfred Molon If, as you say, it only needs a 7MP Bayer camera to equal a 4.6MP Foveon camera, then Sigma has already lost the battle. My original question remains, although I choose to rephrase it: how big a print and how close to it do you need to be (more accurately, what angle does a pixel subtend) to see the extra colour resolution in today's Foveon cameras versus today's Bayer cameras? As the pixel size in a 10MP Foveon camera would be smaller than the 4 Bayer pixels in a 12-15MP DSLR, not larger, it could place higher demands on the lenses, not less, and diffraction could be more of a problem. Cheers, David
From: Alfred Molon on 1 Mar 2010 01:53 In article <280220101443477982%nospam(a)nospam.invalid>, nospam(a)nospam.invalid says... > it makes a lot of sense, since competing cameras are 12 mp (and up). Do you also compare APS-C cameras with medium format ones? > the lens isn't the limiting factor, yet. Yes it is when you have 18MP in an APS-C sensor. -- 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: Alfred Molon on 1 Mar 2010 02:03
In article <280220101443447779%nospam(a)nospam.invalid>, nospam(a)nospam.invalid says... > a sensor with three layers is going to be much more complex to > manufacture than one with only one layer, not to mention that there > isn't the manufacturing volume to keep costs low. Most modern chips have multiple layers. > also, the thickness of each layer must be held to extremely tight > tolerances or there will be a colour shift, Generally speaking every semiconductor manufacturing process must be kept in tight tolerances to maximise the yield. > and to help address that, > foveon has said that *each* camera has to be individually calibrated, > adding yet another expense. But the camera calibration step does not depend on whether the number of pixels is 4.6 or 10 million. -- Alfred Molon http://www.molon.de - Photos of Asia, Africa and Europe |