Petzl Professional 2015 | Page 133

132 KEY POINTS ABOUT LIGHTING Making an informed choice With the growing number of headlamps now on the market and the different technologies being used, some explanation is necessary to choose the headlamp best suited to your needs. Different ways to use the available energy according to usage Brightness or burn time: A question of balance Brightness and burn time are two inextricably linked parameters of any headlamp, regardless of its lighting technology. For a given quantity of energy, increasing the brightness automatically decreases burn time, and vice versa. Headlamp energy source: - batteries - integrated rechargeable battery Brightness (lumens) Burn time (hours) or Favoring brightness to the detriment of burn time Favoring burn time to the detriment of brightness Lighting power: the shape of the beam directly affects lighting distance. Lighting distance depends directly on lighting power, but mainly on the shape of the beam. In fact, given the same light output, lighting distance will differ depending on the shape of the beam. For example, 100 lumens of light will project to 40 meters with a very wide beam, but up to 100 meters with a narrow beam. 100 lumens 40 m 100 lumens 100 m Note: For a compact headlamp worn entirely on the head, the energy source (standard or rechargeable battery) has a limited capacity in order to reduce s ize and weight for the sake of comfort. In spite of the improved performance of today's LEDs and batteries, this still limits the capacity of a headlamp to provide both significant brightness and long burn time.