Flip-Diffuser
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Adding Flood
Capabilities to a Headlamp
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There are several possible ways to create a headlamp that offers both spot and flood capabilities:
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The beam can be made adjustable by adding a variable-focus reflector behind the light source, coupled with a rotating head. The venerable Maglites use this approach (with limited success in my opinion), but it's one that probably needs to be incorporated into the product from the beginning and thus is not a good retrofit candidate for the EOS.
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A second set of smaller, flood LED's can be added to supplement the primary Luxeon LED, a design approach that can be seen in new products like the Princeton Tec Apex and Black Diamond Spot headlamps. It's one, however, that again needs to be engineered into the product from the start and that also increases operational complexity (since there now multiple sets of LED's, each with multiple power levels, that need to be controlled).
Both of these products, incidentally, have features that probably still make them less appealing to backpackers than the EOS. The Apex is overkill for most hikers and the new BD Spot is unregulated and flickers on low power settings.
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Some sort of lens, either fixed or variable-focus, can be placed in front of the beam to alter its character. Example of fixed-focus lenses include the Surefire Beamshapers, some of which offer flip-up capabilities.
Surefire Beamshaper F04
Surefire flip-up Beamshaper FM24
It's conceivable that such lenses could be affixed to the front of the EOS, but they'd add a fair amount of weight (relatively speaking) and some cost more than the EOS itself. Likewise, a variable-focus lens might also be possible, but I'm not aware of one that exists in a form that could be easily retrofitted to the EOS. -
By process of elimination, it can probably be concluded that the easiest method to retrofit flood capabilities to the EOS is to add some type of sliding or flip-away diffuser. A diffuser works by scattering the otherwise focused light beam so that it covers a broader area. The downside is that any diffuser will absorb some amount of light during this scatter process. There's also the risk that it may also over-diffuse the light so that higher headlamp power settings are necessary to perform the desired tasks.
Tikka XP: A Near Miss?
The
Petzl Tikka XP, which has only recently begun shipping, is an example of a
product that incorporates such a diffuser into its design. Unfortunately,
the output of this new headlamp, which is probably the EOS' closest direct
competition, is unregulated, which means that light levels fade continuously
as the batteries are drained. The EOS, on the other hand incorporates
electronic "booster" circuitry that maintains fairly constant
output even as battery voltage drops.
In addition, some early field reports suggest that the Tikka XP's sliding diffuser may, in fact, over-diffuse the beam, requiring the lamp to be set to a high power level in order to function well in camp. I have not yet experimented with this lamp, so can offer no personal observations, but will say that if a manufacturer were going to error on one side or the other, it would probably be preferable to under-diffuse the beam, since additional diffusion is easy to add-on (while the converse is not true).
Nonetheless, the Petzl diffuser design seems to have resonated with those observers who have commented thus far through online forums. It's also a design that I wouldn't be surprised to see Princeton Tec emulate in the next iteration of their product. So until the EOS II is available, a flip-diffuser equipped, original model EOS may be the best all-around headlamp for backpackers that current technology has to offer.
Flip-Away Door
Some enterprising backpackers have suggested that diffusion can be added to the EOS simply by attaching a piece of tape of some sort over the lens. I made, in fact, exactly this recommendation through posts on a couple of outdoor forums earlier this year. As I've discovered since then, however, this method is not very convenient if one needs to switch frequently between diffused and non-diffused modes. Further, the tape that I think works best for this purpose (see main article) leaves a sticky reside on the front and sides of the lamp wherever contact is made.
So rather than attaching the tape directly to the headlamp, a better solution is to apply it to a door than can be flipped away from the lens when it's not needed.