Originally posted by techmulla Why don't pentax use this technology in its upcoming model. it is supposedly better than the rest of the image processing sensor technology.
Any tech gurus out there, comments will be welcomed
Foveon X3 is not superior to the regular CFA CMOS sensors. Instead the current implementation is quite a bit inferior. For example there is no correlated double sampling for the photosites, thus the reset noise remains a problem. The total read noise is an order of magnitude higher than that of the modern sensors, like the one in the K-5. In addition there is plenty of chroma noise due to the awful colour separation of the technology. Also the green, and especially the red layers provide rather unsharp image data due to crosstalk.
The dynamic range is also lower than that of the modern competeting models - this is because of the excessive noise. It is many stops less than that of K-5 for example.
The colour accuracy is notoriously bad and unfortunately also impossible to fully fix due to metameric failure (which is in nature similar to what happens when one uses led lights to illuminate a photograph - the colours can be perfectly fine, but they can also be horrible and not fixable).
The resolution is very low due to the low pixel count. Also the bottom layers are less sharp than the top one. The red one especially can be bad.
Assuming that the patent US 2010/0155576 filed on Apr 11 2008 describes the sensor in SD1, we can confidently say that that sensor is a massive improvement over the current generation Foveon sensors. This patent describes a sensor with CDS ( -> far less read noise) and a novel and pragmatic approach to some of the problems the three layer pixel structure creates. Namely, there are four times fewer pixels on the red and green layer than on the blue layer. The loss of resoution is neglible and QE will be higher than with a homogenic structure.
However, even that sensor will still be plagued by the colour issue as that is due to the very nature of the colour separation. Also the separation will be as weak as before, increasing noise somewhat.