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Flashlight Enthusiast
Flashlights! Ah, what a wonderful thing. A small portable object that emmits light! How enchanting!
However, capturing and quantifying the results of this light output so that it can be compared in some way with the light output of other flashlights is a very difficult task. Light is what we use to see things, or to take pictures. To turn around and try to take a snapshot of the light itself is fraught with difficulties.
I was very interested in the software mentioned on the review forum whereby a person can composite a bunch of white-wall beam shots into a single beam profile. I was also interested in coming up with some scheme whereby a lightmeter is used to measure the center of the hot spot, 50 percent out, 100 percent out (at the edge), and finally at the corona to get a spill measurement.
And I still am interested in both these things, but neither of them alone promises the sort of result I want. Because even given that we can capture what the eye really sees with a white-wall beam shot, that is only one part of what the beam is. And even if we can get a good spread of lux measurements, that also is only one piece of desribing what the beam is--much like an integrating sphere measurement of total lumens output is only one piece of information about the beam.
There is so much more to a beam. How it throws, how it renders, how "bright" it is, and so on.
And one day I had a thought. We all know that you get better pictures from your camera if you have lots and lots of light on the subject, right? So instead of standing back where the flashlight is and trying to capture what the beam looks like to the user--which we're never ever successful at--why not separate the camera and the flashlight? Why not have the camera up fairly close to the object being illuminated, be it a tree or a mail box or a shed, and have the flaslight 10, 20, 50, 100, etc, feet away? The brighter the beam and the better it throws, or the closer it is, the better the picture, right? And presumably, one could aim the light off of the object by varying degrees to capture the spill light. Why fight against what the camera wants to do? It doesn't want to capture light itself; it wants to USE light to capture an OBJECT and the more light the better you capture the object. Right?
I wanted to use this technique in my review of the A2 and L2, but I haven't gotten around to getting outside with the camera and tripods and flashlights to see what kind of results I will get. But I will do so sometime in the next couple weeks. It may be that this is a bad idea and that it won't work out very well. So be it. In any case, for the time being, I wanted to bring it up for discussion.
Because, as Ginseng said on the phone to me the very first time we talked, if we're serious about our hobby and we want to do justice to the lights we examine, we simply have to do better than a single lux measurement at 1 meter. Heck, even here it should be noted that you can move the light meter to varying distances and use the inverse square law and arrive at different lux @ 1 meter numbers. A flashlight beam is NOT a single number. And don't even get me started on how almost all flashlight companies (SureFire being the gleaming exception) exaggerate the numbers and combine them in dishonest ways--for example by quoting runtime to near absolute battery depletion with like 10 percent of starting lux, together with the lux or lumens measurement taken with super fresh hot off the charger batteries. It's lying to one degree or another. But I'll cut myself off here.
So anyway, what do people think? Does this idea have any merrit?
However, capturing and quantifying the results of this light output so that it can be compared in some way with the light output of other flashlights is a very difficult task. Light is what we use to see things, or to take pictures. To turn around and try to take a snapshot of the light itself is fraught with difficulties.
I was very interested in the software mentioned on the review forum whereby a person can composite a bunch of white-wall beam shots into a single beam profile. I was also interested in coming up with some scheme whereby a lightmeter is used to measure the center of the hot spot, 50 percent out, 100 percent out (at the edge), and finally at the corona to get a spill measurement.
And I still am interested in both these things, but neither of them alone promises the sort of result I want. Because even given that we can capture what the eye really sees with a white-wall beam shot, that is only one part of what the beam is. And even if we can get a good spread of lux measurements, that also is only one piece of desribing what the beam is--much like an integrating sphere measurement of total lumens output is only one piece of information about the beam.
There is so much more to a beam. How it throws, how it renders, how "bright" it is, and so on.
And one day I had a thought. We all know that you get better pictures from your camera if you have lots and lots of light on the subject, right? So instead of standing back where the flashlight is and trying to capture what the beam looks like to the user--which we're never ever successful at--why not separate the camera and the flashlight? Why not have the camera up fairly close to the object being illuminated, be it a tree or a mail box or a shed, and have the flaslight 10, 20, 50, 100, etc, feet away? The brighter the beam and the better it throws, or the closer it is, the better the picture, right? And presumably, one could aim the light off of the object by varying degrees to capture the spill light. Why fight against what the camera wants to do? It doesn't want to capture light itself; it wants to USE light to capture an OBJECT and the more light the better you capture the object. Right?
I wanted to use this technique in my review of the A2 and L2, but I haven't gotten around to getting outside with the camera and tripods and flashlights to see what kind of results I will get. But I will do so sometime in the next couple weeks. It may be that this is a bad idea and that it won't work out very well. So be it. In any case, for the time being, I wanted to bring it up for discussion.
Because, as Ginseng said on the phone to me the very first time we talked, if we're serious about our hobby and we want to do justice to the lights we examine, we simply have to do better than a single lux measurement at 1 meter. Heck, even here it should be noted that you can move the light meter to varying distances and use the inverse square law and arrive at different lux @ 1 meter numbers. A flashlight beam is NOT a single number. And don't even get me started on how almost all flashlight companies (SureFire being the gleaming exception) exaggerate the numbers and combine them in dishonest ways--for example by quoting runtime to near absolute battery depletion with like 10 percent of starting lux, together with the lux or lumens measurement taken with super fresh hot off the charger batteries. It's lying to one degree or another. But I'll cut myself off here.
So anyway, what do people think? Does this idea have any merrit?