What is the practical difference between 100, 120, 140 and 170 lumen output?
Your eyes respond to light in a logarithmic way. As such, small differences in light output cannot be seen. It generally takes a 40% increase in light output for you to notice a small (slight) increase in light output – the difference between 100 and 140 lumens or 120 and 170 lumens. The average person will not see a 20% increase in light output – the difference between 100 and 120 lumens, 120 and 140 lumens or 140 and 170 lumens. However, the differences in LED efficiency can have a significant affect on runtime. In general, the amount of power needed to generate the maximum output is the same in all cases. The higher light output is the result of higher LED efficiencies. The maximum power setting is typically less than half as efficient as the next lower setting. This is due to pushing the battery, power supply and LED past their optimum points in order to achieve the maximum light output. In contrast, the lower power setting are operating in their most efficient ranges. Thus, a 170
