I am with you, i think it is absolutely pointless and offers very little in the way of actually improving things.
A set up with 2 focal lengths would have been much more useful.
I also concur.
No difference in file size, or image quality. ISO is identical, as are the number of unique colours recorded. Shutter and aperture are identical too.
Either we're only getting images from the colour sensor anyway, which indicates there's a major issue, or the dual lens setting is pointless.
But, surely, if the images look identical, and give identical exif data, the software isn't doing anything different in either case. If there was more image data in the dual lens shot, the file size would be bigger, and other params would be different.
Curious about what you said, I ran a quick test. Darkened room, but not totally dark, no flash. 3 images taken using, dual, single and mono.
The shutter speed for all 3 was 1/20s. For the dual and single images, ISO was 804 and 826 respectively. For mono, that rose to 986. All at f2.0
Visible noise in the dual and single images is identical, on a dark area at 100%, to my eyes on a properly calibrated monitor. The mono, despite the higher ISO shows lower (or at least less debilitating) noise, which is perhaps to be expected as only luminance noise is in play whereas the others have colour noise as well.
It's not a scientific test, granted, but I'm still unconvinced about what the dual sensor option actually achieves.
it is probably only of any use when using the depth of field mode, other than that it's pointless.
Both shoots was made at the same condition: sunset time, indoor, without artificial light; HDR and flash disabled. Obviusly the two images are compressed for the upload here.
First shot was made with the twin sensor setup; the second with only the color sensor.
It seems clear to me that the monochrome sensor is used in low light situations to capture more light. In this case the noise level is similar between the two shots and very low; but in other scenes I found myself with a lot of noise with only the color sensor. However, the level of detail in the twin sensor shot is clear.
P.S.: In the shot with the color sensor, despite having tried several times, the subject blur doesn't fail.