The Brinkman works well for swirl finding because its light output is reasonably bright, doesn’t diverge too severely and most importantly is extremely uniform.
It’s the uniformity of the beam that allows you see the surface defects rather than artifacts of the light beam. If you shine most flashlights on a uniform surface (a movie screen would be ideal but a flat white painted wall works well) you’ll see brighter areas, darker areas, shadows, edges and various visual artifacts of the flashlight’s illumination components.
The brinkmann’s spot looks more like a fuzzy ball of light. This comes from the Brinkman’s very small xenon lamp, the lamp's very, very small tungsten filament and the flashlight’s dimpled parabolic reflector.
Most flashlights are built to simply “throw light out there� so lights that work well for swirl finding are few and far between.
LED flashlights tend to be especially bad because the geometry of the LED’s semiconductor die and plastic envelope usually produce very distinct beam irregularities. Getting an LED to efficiently project uniform light requires skilled optical design.
I haven’t tried a Surfire light yet (mostly because I’ve had an aversion to CR123a batteries) but it’s looking like I just might need to now. Besides being really well designed and built they do actually concentrate on the optics (Surefire’s roots are in optics, not consumer products). Their reflector design is similar to (and I’m sure better than) the Brinkmann’s. And they have LED units so I won’t be burning through CR123a’s at a painful rate.
I’ve converted all of my C and D cell MagLites to LEDs, both with Mag Instrument’s lamps and with aftermarket conversion lamps. They’re fine for simple illumination but I find them very poor for swirl finding. (Plus, I don’t like waving heavy aluminum clubs over a finish.)
PC.
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