Colour is everywhere underwater, but as a diver, you would be aware that without artificial light, the colours become muted as you descend. Using lights fills in the lost colour. Different diving situations require different dive lights. Dive lights vary in brightness, beam pattern, burn-time and size. Experienced divers have found that no single light is adequate for all situations.

CHOOSING A DIVE LIGHT

BULBS

The bulbs used in dive lights are classified according to the material that generates the light. With diving lights, the whitest light will result in the truest colours underwater. Typically, these are:

Halogen
Xenon
LED, or
HID

Halogen bulbs are the cheapest, but produce the least white light. Commonly, they have been the primary choice for dive and video lights. They are largely being replaced with HID lights.

Xenon bulbs are a good balance between brightness, cost and burn time. Many older popular dive lights use Xenon bulbs.

LED's offer comparable or better brightness to Xenon bulbs, but use far LESS power and therefore give substantially LONGER burn times for any same given battery supply. They are also the HARDIEST bulbs with the LONGEST expected bulb life. These types are the most popular dive lights, however are more expensive than Xenon bulbs. They are however, much cheaper than HID.

HID's are the BRIGHTEST and provide a lot a light for the power they consume. The drawback is that HID lights CANNOT be repeatedly turned on/off, without excessive battery brain and wear on the bulb. Generally, you turn them on just before entering then leave it on until you exit the water again. Also once turned on, you must wait several minutes before turning off. HID's also generate a LOT of heat.

REFLECTORS

Reflector shape also greatly affects a light's characteristics. They either concentrate or spread the beam. A concentrated beam is brighter, however a beam with greater spread has better coverage, - so a balance needs to be made depending on what you are doing with the light.