Such a waste of photons ....
Does it bother anybody else that their lights illuminate the tops of trees that are 100 ft away?
All this effort to get a lot of lumens in front of us, and so much of it goes up above our horizons where it is completely wasted.
Take a look at the tunnel shots in the Lights Shootouts, and notice how well lit the ceiling of the tunnel is. Isn't that all just wasted lumens? We need little mirrors to extend out on the top of our lights to get some of those lumens back onto the ground in front of us and straight out in front of us to a height of, say, 6 feet.
Have you ever tried to ride in the forest trails with descents & uphills?
This subject has been discussed before and depending on intended use ( road or trail ) the upward spill is either a bonus or a waste of lumen as you suggested.
Originally Posted by Godlikedog
For trail use the upward spill is quite useful as long as it is not excessive. The last time I experienced this in the raw was just before the fall season hit and the forest spiders were really going full tilt. Somehow these spiders have a knack for building webs between the trees that line the trails. Since they are somewhat small ( about the size of a quarter ) and brown they aren't real visible unless you have a good amount of light on them. This doesn't usually happen until you are right up on them. Most times the center of the webs are about head high and will be right in the most useable section of the trail. I've had spiders crawling on my glasses on more than one occasion...So...to avoid spiders you either need to have some upward spill on your bar lamp or use you helmet light more than you have to.
Then there's the trail Whoop-de-do. This is a trail feature that incorporates quick roller-coaster down-up's and up-down's. When moving at speed at the bottom of one of these your upward spill helps illuminate the up-coming terrain of the climb as you approach.
As I said before, if you have too much upward spill it means you are losing useable output that could be better used if refocused more forward. So far I've only had one lamp that met that criteria. Yes, it was lighting the tree tops more than it needed to. To address this issue I attached a small homemade hood made from thin cardboard and lined it with aluminum foil. Actually worked quite well and returned some light down to the ground. Eventually I bought other lights and now use those so for me it is no longer an issue.
(* Please note that lamps that provide more upward spill tend to be more designed for flood-beam coverage than longer throw spot-beam coverage. If you want more light coverage to the sides expect to see some Owls sitting in the tree tops.
Summarizing, I think it safe to say that when it comes to upward spill; Better to have some and not need it than to need some and not have it.
I'd rather be able to see low branches before they hit me. People used to cope before the squillion lumen lights came out ...can afford to lose a bit of light these days
What exactly is a rigid hard tail?
Originally Posted by Godlikedog
Nope, doesn't sound right to me because I actually bias my bar mount lamps to aim more light up higher. I've found that illuminating more of my surroundings, including upper parts of the trees, keeps my vision from struggling to adapt to lit and unlit areas. And I don't want a sharp cutoff at a such a low height because I want to see what's hanging from the trees and up the next rise on the trail.
One of the more serious incidents I've had while riding at night was due a thorny vine was hanging across the trail at face height on the up side of a whoop-de-doo. I didn't see it because my lights at the time just didn't have the lumen output or beam spread to illuminate it and the vine caught me right across my glasses and tore up the bridge of my nose. I shudder to think what would have happened had I not been wearing eye protection.
I never thought about spiders; good point. I don't encounter them where I live now, which is pretty arid, but growing up in the mid-west, it seemed that they took it upon themselves to string their webs across the sidewalks as much as they could. Nowadays I imagine that the chipmunks play a game of chicken by darting in front of mountain bikers across the trail.
I guess I'm noticing it more because I have a Gemini Olympia that I put wider angle optics on, and hey!, now I can see the treetops! When I am riding, I am frustrated by how simple the optics on these things are, even the original optics, which are the same off the shelf optics, just narrower. It seems like a lot could be done to even out the intensity and get the lumens in more appropriate places. I guess I should have looked into the Light and Motion products.
I have a Xera and an Olympia, and they suit my needs quite well, but I can't help but to want optimize it. And isn't that the spirit of this sub-forum? Isn't that what being a light nerd is all about? The engineer drive to get as many lumens as possible per watt, per gram, per dollar, and to figure out how they should utilized best(ly). It's optimizizing ratios that makes these things compelling, that makes us get obsessed with the details for lengthy periods of time. Making something strong isn't that interesting, but making something strong and lightweight becomes an interesting and never ending challenge. We've got lumens/watt, watts/gram, watt-hours/gram that we want to maximize, and pupil dilation we need to maximize, too. At some point, and I think I'm there with my lights, particularly with the hot spots, my pupils are just contracting if I go brighter.
I guess for those of you that just want a bright narrow beam with a lot of throw, the issue is simpler. I want a bit of that, but I want an even, broad flood also. 'Even' being a key word; the hot spots and abrupt lines of brightness changes really screw with your visual processing.
Originally Posted by Cat-man-do
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