I will keep my eye on this, hope to get my D26s soon.. Slow boat from China.
Review: DGX 600 vs Xtar D26 vs $22 eBay light
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the_ocean
Registered
OP
Just curious, once you remove that O-ring, what stops you from just pulling the button straight out when the light is fully assembled?
the_ocean
Registered
I took apart one my lights and it has a dfferent looking button than the above screenshot.
The tang on the button is what limits its it to a 1/4 turn. It's most likely present on the other version as well.
The ridges on the sides are probably very helpful in preventing the locked button situation. But I don't see any reason to keep the O-ring in there anyway.
The tang on the button is what limits its it to a 1/4 turn. It's most likely present on the other version as well.
The ridges on the sides are probably very helpful in preventing the locked button situation. But I don't see any reason to keep the O-ring in there anyway.
OP
A couple of point about lights in general. (I design lighting solutions for TV)
Light is subject to the inverse square rule. To compare the lumen measurement you need to know at what distance it was measured
So if a light has a measured output of 1000 lumens @ 3', at 6' it will be only 250 lumens, but at 1.5' it will be 2000 lumens
Input power with LED can be misleading too. Pushing more power through an LED doesn't make it bright, indeed the opposite, the trick is efficient cooling to dissipate the heat. Getting it wrong (or right) can affect the output by as much as 100%
Beam angle make a huge difference too, as does the quality of the reflector
So advertised lumens and Watts isn't a good way to compare, but they do make nice headlines on packaging
Light is subject to the inverse square rule. To compare the lumen measurement you need to know at what distance it was measured
So if a light has a measured output of 1000 lumens @ 3', at 6' it will be only 250 lumens, but at 1.5' it will be 2000 lumens
Input power with LED can be misleading too. Pushing more power through an LED doesn't make it bright, indeed the opposite, the trick is efficient cooling to dissipate the heat. Getting it wrong (or right) can affect the output by as much as 100%
Beam angle make a huge difference too, as does the quality of the reflector
So advertised lumens and Watts isn't a good way to compare, but they do make nice headlines on packaging
lucca brassi
Contributor
The tang on the button is what limits its it to a 1/4 turn. It's most likely present on the other version as well.
The ridges on the sides are probably very helpful in preventing the locked button situation. But I don't see any reason to keep the O-ring in there anyway.
maybe is O ring there to prevent sand particles to stuck between lamp enclosure and button.
@ diving Dubai
you can operate with lumens at optical source point ( it is point source, therefore, the transmitting surface minimum )
as you have said
Light is subject to the inverse square rule.To compare the lumen measurement you need to know at what distance it was
measured
with distance you don't have point source anymore but you have spherical surface with radius on distance from source in that case you have
LUX . Lux definition is 1 lx = 1 lm/m2 = 1 cd·sr/m2 so you can't talk about 250 lumens on 6' but you can talk about (source lumens) / ( part
of sphere )depending on distance ( you need also source point angle to determine cone)
Lux to lumens (lm) conversion calculator
and that is not what you will see...... because you see light reflected from surface ;-) which also absorbs some wavelength and you see less light as it could be measured .....
The ridges on the sides are probably very helpful in preventing the locked button situation. But I don't see any reason to keep the O-ring in there anyway.
maybe is O ring there to prevent sand particles to stuck between lamp enclosure and button.
@ diving Dubai
you can operate with lumens at optical source point ( it is point source, therefore, the transmitting surface minimum )
as you have said
Light is subject to the inverse square rule.To compare the lumen measurement you need to know at what distance it was
measured
with distance you don't have point source anymore but you have spherical surface with radius on distance from source in that case you have
LUX . Lux definition is 1 lx = 1 lm/m2 = 1 cd·sr/m2 so you can't talk about 250 lumens on 6' but you can talk about (source lumens) / ( part
of sphere )depending on distance ( you need also source point angle to determine cone)
Lux to lumens (lm) conversion calculator
and that is not what you will see...... because you see light reflected from surface ;-) which also absorbs some wavelength and you see less light as it could be measured .....
Last edited:
@lucca brassi
I hear what you are saying. I was keeping it simple and using units in the contexts of the discussion in the thread.
As you point out point source measurements are worthless, and generally conceived by calculation.
To properly compare side by side you need a photo metric diagram which gives light output over a given distance and with given beam angle - or more accurately field angle
We could get into the differences in the spectrums between different units as well as colour temperatures and the like, but in the real world (as observed by the naked eye) these have very little effect unless there are major differences.
My point being is that the output quoted by the manufacturer isn't a good comparator and neither is the input power.
What is needed is someone to conduct an extensive side by side testing and review of units and publish it for all to see.
I hear what you are saying. I was keeping it simple and using units in the contexts of the discussion in the thread.
As you point out point source measurements are worthless, and generally conceived by calculation.
To properly compare side by side you need a photo metric diagram which gives light output over a given distance and with given beam angle - or more accurately field angle
We could get into the differences in the spectrums between different units as well as colour temperatures and the like, but in the real world (as observed by the naked eye) these have very little effect unless there are major differences.
My point being is that the output quoted by the manufacturer isn't a good comparator and neither is the input power.
What is needed is someone to conduct an extensive side by side testing and review of units and publish it for all to see.
lucca brassi
Contributor
IMO :
It is not easy and never has been, but also because such interpretations (simplified) created this whole mess section. Taking advantage of this is just east ebay sellers at the expense of quality Western producers. And in this article talks about cheap eBay lights
It is not easy and never has been, but also because such interpretations (simplified) created this whole mess section. Taking advantage of this is just east ebay sellers at the expense of quality Western producers. And in this article talks about cheap eBay lights
My D26 from the slow boat finally got here. I will be testing it this weekend in the Blue Grotto. I will report back.
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