I'd like to add floodlights mounted to my house to light up my yard at night and I'm trying to figure out how bright a fixture I should buy. I've Googled a ton and found plenty of calculators to do the math, i.e. how high I'm mounting them and how much yard I'm trying to cover which results in this many foot-candles or lux. But those don't tell me anything about whether the results would make my lawn look dimly lit or like daylight.
Is there a set of rough guidelines or rules of thumb? I don't need to light it up like a night game at an athletic field but I want it brighter than just a security light. I need to be able to walk around with my dog and clearly see everything. I'd like to err on the side of more light, not less.
The lawn I'm trying to cover is 65x80 feet (about 20x25 meters) and I'd mount the lights about 20 feet high.