Shouldn't 16 bit mode display more than 256 shades/channel?

I’m not sure that I fully understand the difference between Photoshop’s 8-bit mode and 16-bit mode.

I think I’m correct by saying that 8-bit provides 256 (2 to the 8th power) shades in each of the red, green, and blue channels, for a total of 16,777,216 (2563) colors. And that 16-bit provides 65,536 (2 to the 16th power) shades per channel, for a total of 1.E+77 (65,536 to the third power) colors.

If I’m correct, then why am I limited to only 256 shades per channel when selecting colors from the color picker when in 16-bit mode? Is it because the color picker isn’t setup to handle 16-bit color, even though I have Photoshop CS, which supports 16-bit for most core operations? My thinking is that providing more shades in the color picker would require decimals, so the Photoshop designers decided that allowing more choices in the color picker would be unwieldy. I’m assuming black would still be represented as 0,0,0 and white as 255,255,255.

If I make color correction in 16-bit and then switch to 8-bit, there should be some color shifting and loss of detail. Yet, I have not been able to see this loss even when looking at individual pixels at full zoom. Photos seem to have more details when shot in 16-bit mode, so why don’t those details become lost when converting them to 8-bit? Perhaps I’ve been watching the monitor too long and am not picking up on subtle differences.

Any information you can give me on color differences will be greatly appreciated. Thanks.

Cathy Keifer