Originally Posted by
Spoonrobot
You're not wrong and neither was anyone else. But more lumens are only one piece of the puzzle. Upgrading to a light that has 300 additional lumens is not going to benefit if those lumens are wasted as flood, as the lux at distance will be the same or less than the prior light with X-300 lumens. Basically if you upgrade just lumens it's possible all that's happening is a wider area is now being illuminated but since washout is due to another light source overriding the luminous flux of your light source a more concentrated beam is needed. If the OPs current light is distance measured as 50m to 0.25 lux and his next light is 300 lumens brighter but has the same 50m to 0.25 lux all he's done is increase the ouput and increased the candela measurement but not done anything to overpower being washed out.
Yes, lumens are just one part of the puzzle but they are an important part. Most of us can actually
see where our lights are going and have some clue as to what the effect of adding more lumens has. Additionally, most of the lights that are available are of about the same design and construction. Upgrading the lumens puts more light in about the same spot as a similar light with less output. The common comment of "you are just spraying light into the trees" is usually wrong because most of us aren't going to use lights with that wide of a beam. Please assume that we aren't stupid.
As for davei1980's light, if he could increase the output by 300 lumens on the
same light, the lux would increase as well as he would be using the same optics with more output. That's the way that lux works. It's lumens/area. Increase the lumens but don't change the area and you have a higher lux. To have the same lux as before with more lumens, the light would have to change the area of the beam. That's not going to happen.
Originally Posted by
Spoonrobot
What he should do is look for a light with higher lumens as well as a higher beam rating. A light with +300 lumens and distance measured as 100 meters to 0.25 lux is going to be significantly brighter, with more throw and will be more resistant to being washed out by other light sources.
First off, I really doubt that you could get a 0.25 lux at 100 meters with the light davei1980 is using. The beam...even shaped ones...increase in area with distance. Assuming a 25° reflector angle which is common for many floody LED lights, a cone would have an area of 1100 square meters at 100 m. To get a 0.25 lux at that distance, you would need a light source of over 4000 lumens. His light isn't putting out that kind of power. I suspect that his light is going to struggle to put out 0.25 lux at 10 m since the output isn't going to be anywhere close to 1200 lumens on a 3 AA light, especially considering that davei1980 is complaining light washout.
Originally Posted by
Spoonrobot
The issue with bike lights, among many, is that they often do not follow the FL-1 standard and play loose and fast with what "lux" means as well as overstate brightness and battery life. So it can be hard to determine when an upgrade is actually and upgrade and not just a different beam pattern or proprietary battery pack.
I agree that lights play fast and loose with whatever rating they give. But, as long as you don't take their word for those values, you can still compare one light to another. The Cree Magicshine knock offs I use have an output of about 800 lumens which seems to be fairly standard for that kind of light. I have a Cygo light of known output that I can compare it to. I also have chosen lights that have a fairly narrow beam so that most of my light isn't "sprayed into the trees". I had early Magicshines and that was one of my problems with them. Not that the sprayed light into trees...it takes a significantly wider beam to do that...but that their beam was a bit too floody.