Hi All,
I have been thinking about flashlight/torch (I'm going to use 'torch' from now on - it's shorter) outputs, as you do. I have noticed quite a difference in stated lumen output across many torches of differing size, capacity, design, etc. Then I get reading how some people question the manufacturers stated output. Delving further, I read how some people setup their test equipment and rigs etc, and then rattle off the measurements they made and how these measurements vary (considerably I may add) form the manufacturer's stated figures.
Surprise, suprise, their measurements are significantly less than the manufacturer's stated claims. Then a clamour arises on forums like this about how manufacturers make unrealistic or inflated claims about their torch's output. How laboratory testing varies from real world conditions, blah, blah, blah, etc, in an effort to discredit the manufacturer's stated figures. This made me doubt the claimed outputs of my rather modest collection torches.
Well now, I thought time to do some testing of my own to see if the manufacturer's claimed output of one of my sample torches was true. So I looked in to how to test light source outputs. Well, what do you know! It turns out that to do accurate testing (and the key word here is accurate), you need some real expensive gear and a reasonable amount of know how. Hmmmm! This doesn't look like it is going to be a feasible excercise. So then I revisit how many of the regular Joe's out in the real world actually did their testing. I saw all kinds of jury rigged set ups involving pipes, opaque and translucent sheeting, black masking/packing tape, - a real Macgyver operation. After all this, I read in many places just how inaccurate these testing setups and practices are in obtaining accurate output figures.
If this is the case, don't these people realise how inaccurate their reading are? Don't they realise that they are on quicksand when trying to base an argument on how a manufacturer's claimed figures are inflated/unrealistic when their own figures are much more inaccurate than the manufacturer's figures? The manufacturer has to test their products to the ANSI/NEMAFL1 standard to be of credibility. If people doubt the manufacturer's claimed outputs, then they should test the same torch using the same or higher standard (if there is one), which means using the proper expensive test gear in an exacting environment. Who do I believe? Regular Joe's who have every right to be suspicious of any manufacturer in whose interest it is to inflate claim outputs or do I believe the manufacturers who have to test to an international standard and if actually tested to that standard, the claimed figures achieved? Of course, I'd like to check figures for myself.
So, how do I accurately (to within +/- 0.5% tolerance) test a torch to see if the output actually is what the manufacturer claims it to be? Any suggestions/ideas?