Your eyes can see about eleven f/stops. In other words, you can look outside a window on a sunny day and see the neighbors playing around the house and also be able to see into a cabinet in the kitchen. A camera can only see about half as many f/stops. So it can either see outside the window, leaving the interior of the cabinet black, or be able to see inside the cabinet and "blow out" the windows. The reason I bring this up is just because you think there is enough light for the camera to see and focus on, doesn't necessarily make it so. If you hear your lens hunting for something to focus on, chances are it's too dark and you'll need to turn on a light or two. Other than that, light is light. It's just easier to practice with an abundance of it