A flashlight has a lens or lenses moveable relative to one or more LED or other light source. The beam of light provided by the LED can be focused and provides a uniform light pattern across the range of focus. The lenses are supported on a front housing section and the LED is supported on a back housing section threaded onto the front housing section. Twisting the front housing section closes a switch providing power to the LED, to turn the flashlight on. One or more circuit modules within the flashlight provides various operating modes including an automatic shut-off timer, to preserve battery life, a dimmer controlled by turning an end cap, a blinking function, and/or a current control function to provide maximum brightness regardless of battery condition.