Z2 Fine vs Standard
 

Can anyone explain the difference between the Fine vs Standard settings. I tried cropping and enlarging pics shot with the Standard setting and they lost a lot of sharpness. thanks.

I think the main difference between Fine, Standard is the compression ratio. With high compression ratio a part of the data is lost.
So using Standard you are receiving smaller size, but worse quality, compared to Fine.

I am using Fine quality settings, and taking photos in P mode with ISO set to 50.

Rayfire gave the answer. Higher JPEG compression. I use only the fine setting and would never go below that unless I was running out of space on my card, didn't have a spare and needed to take more pictures. Since I've got 512mB of cards good for over 300 pictures that's not likely to happen unless I go on another 10 day cruise to Alaska. In that case I'll get another 256mB card before I go.