We stock head torches from two manufacturers, both major producers of climbing equipment. Petzl invented the modern head torch and have been making brilliant and reliable head torches for years: few companies come anywhere close to them for quality. One of the very few manufacturers that can "hold a candle" to Petzl is Black Diamond who have produced some very innovative head torches in recent years.
Manufacturers now give the number of Lumens that each torch emits (this figure is always for the best option possible). Although we reproduce these figures, more useful would be the number of lumens/square metre, though even this figure would only be relevant when the batteries were new. Far more practical is the chart showing decline in beam length over time that accompanies each torch.
Black Diamond did not issue lumens ratings for their torches for years as they said that they are misleading as it's impossible to find a measurement system that captures all the important features of light output and light duration. The current system favours lamps that have a strong centre point of light and does not take into account the overall shape of the light output or the strength of the light output outside the centre point. Therefore a lamp that projects a very strong pinpoint of light with a very weak surrounding beam might receive a longer and further distance rating than a lamp that offers a stronger wide beam with very strong pinpoint centre. Black Diamond pioneered the system of giving a beam length over time now commonly used by most head torch manufacturers - however they now give lumen ratings as well.
It is important to be aware of this when attempting to compare torches from different manufacturers, and also that the performance figures quoted from most manufacturers, including Petzl and Black Diamond, are not that realistic as they are obtained at 20°C – hardly the temperature at which one normally uses a head torch!
For those who are interested in head torch comparisons, the Polish website, www.light-test.info tests pretty much all the torches out there and has some very good comparative tests between the main types as well as well as ingenious modification tips.