Good evening,
I do not agree. The pixel is not subject to definition. It is a physical item on the sensor. So the question remains, is a given pixel, i.e. a given piece of silicon, exposed to R, G and B light or always to the same colour.
Hermann-Josef
According to your definition of a pixel ;-), of course itâs only exposed to one colour, because the matrix is fix.
exactly
Ingo, thank you very much for the clarification! So in the end the âpixel shiftâ is rather similar to taking four separate exposures and then averaging them in an optimum way.
I am an astronomer and have used CCDs for more than 30 years. In the end this is very similar to our practice called âditheringâ. We move the telescope between exposures of the same object by (hopefully) integer number of pixels to avoid e.g. that the object we are studying happens to lie on a dead or hot pixel.
Hermann-Josef
The term âpixelâ is very much subject to definition and context. Less ambiguous terms for a single sensor element are âphotositeâ or âsenselâ. An array of filters of a repeating color pattern covers the sensor. The pattern used on Pixel Shift-capable cameras is called the Bayer pattern. When shooting in Pixel Shift mode, a shot is taken, the sensor is moved one photosite up, another shot is taken, right, shot, down and last shot. The filter stays static relative to the sensor. The end result is that a single point of the scene exposes four photosites (R, G, B, G).
@Morgan_Hardwood
Thanks for the clarification. You confirm what I had written above. I agree that one has to differentiate between the pixel in an image ( i.e. a digital item) and the physical pixel on the sensor. What is meant usually follows from the context. For me it was important to understand, that the Bayer-matrix is indeed fixed with respect to the sensor.
Hermann-Josef
Next days I will try to make an improvement for high ISO Pixel Sift files. Currently the standard procedure for high ISO Pixel Shift is to use the Pixel Shift combined image for regions without motion and the demosaiced version of the selected sub-image for regions with motion.
For really high-Iso images there is another way which gives gives even less noise in the areas without motion:
Itâs using the median of the demosaiced version of all 4 sub-images. Hereâs an example (left is standard pixel shift combined, right is median of 4 demosaiced frams, image is ISO 51200:
In current version of RT Pixel Shift this can only be used for images which donât need motion correction and also only a few people know about it 
I intend to implement this method in a way that the median of 4 can be used for the parts without motion while using the usual single frame for the parts with motion.
I will keep you informed here.
Ingo
I made a first implementation of using median of 4 demosaiced frames for regions without motion and one demosaiced frame of userâs choice for regions with motion. That works, but the noise difference between regions with and without motion is about 2 stops, which makes the transitions between the regions clearly visible. I will try now to improve that transition issueâŚ
Ingo
