The P7800 has the same sensor as the P7700 plus it has an electronic viewfinder. The discontinued P7100 has the same size sensor. I don't know if it's the same sensor. The older P7000 has the same sensor as the P7100, but the P7100 is a better camera. Both have optical viewfinders and both are available used.
I have both the P7800 and P7100. The P7800 is the better camera, but it costs around $550. The P7100 is still very good and a gently used one can be gotten for under $250.
A nice feature of all of these P series cameras is a hot shoe. I use a small Nikon SB-300 flash for bounce flash with my P7800 and P7100.
