Archived posting to the Leica Users Group, 2018/04/03
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Notwithstanding any other considerations that may have to do with Bayer or other filter schemes, isn?t it still true that in any color sensor, because each photosite has a monochromatic filter over it, that site will receive only one-third (notionally) of the incident white light on it, and greater proportions of any non-white mixture ? but in any case, lose anything from just a bit to a whole lot of the incident light, and therefore have a lower average ISO than an unfiltered monochrome sensor? ?howard > On Apr 2, 2018, at 19:05, Ken Iisaka <ken at iisaka.com> wrote: > > There are many freely available documents on what Bayer sensors are, for > example: > > https://en.wikipedia.org/wiki/Bayer_filter > > "Demosaicing", in the simplest term, is an interpolation algorithm and has > very little to do with "anything blue in the image has to pass through a > red then green grid layer first." > > Here's a description of Foveon sensors, which actually captures blue light > first, then green then red at last. > > https://en.wikipedia.org/wiki/Foveon_X3_sensor > > Because all three colors are captured at the same location, no > "demosaicing" is necessary with Foveon sensors. In addition, no > "demosaicing" is necessary with monochromatic, or rather, panchromatic > sensors, as each pixels capture light from a wider range of wavelength, not > limited to one "color" > > All image sensors in use today have a grid layout. Foveon sensors have > multiple layers to detect light of different wavelengths. Bayer sensors use > separate pixels to capture levels of different wavelengths. > > Here's more explanations about different filter array designs: > > https://en.wikipedia.org/wiki/Color_filter_array > > > > On 2 April 2018 at 15:32, Mark Rabiner <mark at rabinergroup.com> wrote: > >> If there are so many factual errors then why not show us one? Show us how >> the Bayer process really works! Otherwise this is just added to the list >> of >> crass personal attacks which have compiled over the years from you. And >> let's see one of your pictures Ken! >> >> >> >> >> -- >> >> Mark William Rabiner >> Photographer >> >> ?On 4/2/18, 5:16 PM, "LUG on behalf of Ken Iisaka" <lug-bounces+mark= >> rabinergroup.com at leica-users.org on behalf of ken at iisaka.com> wrote: >> >> There are so many factual errors. What Mark describes is Sigma Foveon >> sensors. It has nothing to do with Bayer-layout sensors used by Leica >> and >> most other cameras. >> >> Just go take pictures. >> >> On 1 April 2018 at 03:41, Mark Rabiner <mark at rabinergroup.com> >> wrote: >> >>> It?s the same speed but it can skip having to pass though various >> filters >>> first in the RGB Bayer process. It's just direct. >>> Makes for a far cleaner final result. >>> As I understand it demosaicing means anything blue in the image has >> to >>> pass through a red then green grid layer first. >>> Anything green has to pass though just the red gird layer one first. >>> And if it?s a red rose its fairly direct. Should look good. >>> A black and white sensor has none of that. No grids. No layers. >> Everything >>> direct. >>> Its keeping it simple stupid. I like that. >>> >>> >>> >>> >>> -- >>> >>> Mark William Rabiner >>> Photographer >>> >>> ?On 3/31/18, 12:14 PM, "LUG on behalf of Paul Roark via LUG" >>> <lug-bounces+mark=rabinergroup.com at leica-users.org on behalf of >>> lug at leica-users.org> wrote: >>> >>> On Sat, Mar 31, 2018 at 7:59 AM, chris williams via LUG < >>> lug at leica-users.org >>>> wrote: >>> >>>> ?... >>>> >>>> >>>> Leica was able to use some kind of sensor made in Belgium that >> was >>>> strictly designed for monochromatic images. >>>> >>>> ?... >>> >>> Yes, but aside from not having an R, G or B filter over the >> pixel, the >>> silicon is still the same speed as that under the filters of the >> color >>> sensors. The monochrome's native speed is higher only because >> it has >>> no >>> color filters over the pixels. I don't think the Leica foundry >> has >>> found >>> any breakthrough to increase silicon's native light sensitivity. >>> >>> I'm not knocking the monochrome at all. For street photography >> or >>> where >>> you don't need a filter, it's truly faster and a great tool for >> those >>> types >>> of photography. >>> >>> Paul >>> www.PaulRoark.com >>> >>> >>> ? >>> >>> _______________________________________________ >>> Leica Users Group. >>> See http://leica-users.org/mailman/listinfo/lug for more >> information >>> >>> >>> >>> _______________________________________________ >>> Leica Users Group. >>> See http://leica-users.org/mailman/listinfo/lug for more information >>> >> >> >> >> -- >> Ken Iisaka >> first name at last name dot org or com >> >> _______________________________________________ >> Leica Users Group. >> See http://leica-users.org/mailman/listinfo/lug for more information >> >> >> >> _______________________________________________ >> Leica Users Group. >> See http://leica-users.org/mailman/listinfo/lug for more information >> > > > > -- > Ken Iisaka > first name at last name dot org or com > > _______________________________________________ > Leica Users Group. > See http://leica-users.org/mailman/listinfo/lug for more information