Like most things, the more passion you have for something, the better. Consider if you like, want or need the hobby to provide a certain activity level. Maybe photography will provide enough walking/hiking to meet that need and improve/maintain your health. Maybe you have health issues that your hobbies need to be more sedentary. Things like crafts, puzzles, video gaming, sewing, etc. You also might want to consider if your going to try to accomplish anything else with your hobby other than keeping you busy. Can you find one that benefits someone else as a act of kindness? One that might provide some extra income?
So my suggestion is decide what level of physical activity your want, what other goals you have for your hobby, then build a list of things that fit those needs and narrow it down to the one or two that you think you would be most passionate about trying. Having a couple hobbies is a good idea. Doing anything too often will get old. Even eating steak every night will have you begging for some variety eventually.
Good Luck in making your choices!