Petition to Nikon: low-light DX camera

TaoTeJared · February 2013

So when processing the data from the 3 layers they need to subtract the value(by some factor) of the lower layers from the upper layers to find the value of the red colour, and green. so you are throwing away some volume of light from the upper layers. I think theoretically the volume of light "lost" this way is still less than in the bayer system.. but who knows.. maybe its not as theoretically predicted.. maybe too much of the light is really lost as its goes through the silicon, converted to heat not electricity( the Q.E ?).

It doesn't exactly work the way you speak to the processing of the images, the physical sensor itself does that. It doesn't "throw" away anything, it only captures the a specific range of color at each level. It's to complicated to go into for this thread. In images though, just like bayer sensors, the red hues do create more noise. The largest problem for the Foveon sensor is the dramatic drop in color saturation as the ISO rises - similar to film as well. Sigma doesn't release much if anything about the "issues" or struggles so knowing what the limitations are are just guesses.

I'm with MikeGunter - I don't see any "real" or major improvements for at least another generation or two of systems and for non-photo geeks, trying to sell them on anything with a lower MP sensor would be a major uphill battle and would have to explain why all the marketing in the past was not really correct.

heartyfisher · February 2013

So when processing the data from the 3 layers they need to subtract the value(by some factor) of the lower layers from the upper layers to find the value of the red colour, and green. so you are throwing away some volume of light from the upper layers. I think theoretically the volume of light "lost" this way is still less than in the bayer system.. but who knows.. maybe its not as theoretically predicted.. maybe too much of the light is really lost as its goes through the silicon, converted to heat not electricity( the Q.E ?).

It doesn't exactly work the way you speak to the processing of the images, the physical sensor itself does that. It doesn't "throw" away anything, it only captures the a specific range of color at each level. It's to complicated to go into for this thread. In images though, just like bayer sensors, the red hues do create more noise. The largest problem for the Foveon sensor is the dramatic drop in color saturation as the ISO rises - similar to film as well. Sigma doesn't release much if anything about the "issues" or struggles so knowing what the limitations are are just guesses.

I'm with MikeGunter - I don't see any "real" or major improvements for at least another generation or two of systems and for non-photo geeks, trying to sell them on anything with a lower MP sensor would be a major uphill battle and would have to explain why all the marketing in the past was not really correct.

Re Faveon Layers.. I can see how you would think that .. the marketing blurb shows that each layer absorbs the different colors but that didn't make sense to me. So I dug deeper.

From a Faveon Technical document by sigma "Foveon X3 image sensors take advantage of the
ability of silicon to absorb different wavelengths of light at different depths in silicon."
Which is what I observed in the submarine for water( i think i also remember reading that that effect is due to the high concentration of dissolved silicone in seawater close to the sandy beaches.)

Just had a look at the wikipedia article on the subject and that seems consistent with what I surmised. The wikipedia article http://en.wikipedia.org/wiki/Foveon_X3_sensor

RE the poor high iso performance. I don't think it has anything to do with how film works. The 2 systems (film vs Faveon) uses different physics. in film there are 3 or 4 different layers with different chemicals. in Faveon its the same silicon just different depths. .. if the QE is low and the opacity is high for silicone that would explain why when there is a low number of photon, the lowest layers would not be able to gather many by the time its has to go through the upper layers. ie it has lost a percentage of photons to the upper layers and the opacity of the silicon. and furthermore the value of photons that do reach the lower layer(blue) need to be subtracted from the upper layers to get the required colours(red). Of course I could be totally wrong :-) but for the moment i believe that is a correct assertion.

TaoTeJared · February 2013

What is Faveon? Foveon

heartyfisher · February 2013

What is Faveon? Foveon

you are right :-) sorry ..

Howdy, Stranger!

Categories

In this Discussion

Who's Online (0)

Petition to Nikon: low-light DX camera

Comments