Here is a little comparison based on Pixel Size and Actual Photoshop Percentage between 6 Cameras.
Pixel size doesn't really say anything. 16MP vs 32MP is not really double the size. What matter is the actual percentage in Photoshop to make the image reach the next MP size.
As you can see in the chart, there is a 15% increase from 16MP to 22MP. A percentage that won't ruin your image if you want to make it a little bigger... Now, a full 50% enlargement will introduce artifacts, noise and blur to your image, so you probably won't want to do that...
I do believe in per-pixel quality and noise levels but if you are a studio photographer who shoots at ISO 50 or 100 most of the time, you probably don't care and want 50% more Megapixels to play with. I do see the fact that the Nikon D4 is going to cost double the D800 and have less than half the MP so there has to be something there to make it better but if u want raw huge files the D800 will be the winner no matter how you see it.
Pixel size doesn't really say anything. 16MP vs 32MP is not really double the size. What matter is the actual percentage in Photoshop to make the image reach the next MP size.
As you can see in the chart, there is a 15% increase from 16MP to 22MP. A percentage that won't ruin your image if you want to make it a little bigger... Now, a full 50% enlargement will introduce artifacts, noise and blur to your image, so you probably won't want to do that...
I do believe in per-pixel quality and noise levels but if you are a studio photographer who shoots at ISO 50 or 100 most of the time, you probably don't care and want 50% more Megapixels to play with. I do see the fact that the Nikon D4 is going to cost double the D800 and have less than half the MP so there has to be something there to make it better but if u want raw huge files the D800 will be the winner no matter how you see it.