How much more useful are ever higher pixel densities?

I think as we move forward you get less and less gain from the previous model especially with the a DX body.

I just got a D5200 but I still have a D5100. Just for the hell of it I grabbed a video camera chart and took some test shots with both of them.

The big gain with the D5200 is that it seems to be almost a 1/2 stop faster - maybe 3/4 of a stop. To get the same exposure I had to slow down the shutter on the D5100. That's quite impressive - the D5200 is going to be a fantastic camera for shooting in low light settings.

What I did find interesting is that when I re-sized the images in Photoshop and matched them up I can't see much difference. Shooting a chart is not going to show how it renders color and so forth but as far a resolution - not much difference.

We are at the point that for very little money you can get a high quality product.

The D5200 is a big step up in function from the old model so for me that's what I am paying for.

If I had a $400 budget for a new body I would by a refurb D5100 in a heartbeat.