Wed 22-Feb-12 12:35 AM | edited Wed 22-Feb-12 12:37 AM by PerroneFord
This is like asking about carburetor on a modern racing car. Photosite size IS a significant factor of light gathering ASSUMING the underlying technology is the same. Well, technology has moved on considerably since your D2HS was new.
The light gathering of the 36MP D800 is about 4 times as good as your D2HS, regardless of the photosite size.
Thom Hogan's book, as excellent as it may be, is a guide. Not the definitive work on the subject.
I think if you visit Thom's site, you'll discover that his opinions on this have evolved along with the technology. The well-supported theory now is that high ISO noise performance in print depends on the size of the sensor, not the sensels. On the other hand, a sensor with fewer sensels is less inclined to mechanical blur, making it easier to produce a clean file at full resolution.
Have you downloaded one of the RAW pictures converted to a JPEG that is about 17-18 MB in size and looked at the detail in one of those pictures? If you haven’t I suggest that you do and take a look. Open it at 200% and look at the veins in her eyes and the beautiful peach fuss on her face that look like you need to get out the shaver looking at it at 200%. There is so much detail, look at the mascara above her right eye where she touched it with her brush that you would never see with the camera I use anyway.
And I know that we aren’t going to be looking at out prints at 200% but there is so much detail from this camera. I waited a long time for this camera and might have to change my style of taking picture as a travel-walking around camera but I love the detail it gives. So download this picture and take a look, this one I edited from another post trying to edit it and is my version but you look at the original and tell us what you think. No matter what the 4.9 micron pixel size, this camera looks like it will produce some great detail. Also upload the 22MB library shot, stunning I thought I might be able to read the titles of the books. LOL