Replace a UK C6

[DarinMartell]

It's cold, it's snowing, and I have cabin fever so I am spending ALOT of time on ST. Problem is that I am spending so much time here I am getting the "I need new gear" itch. I have a old UK C6 that I like. Question is are any of the inxepenive ($30 or less) lights brighter or even just as bright but smaller?

[cbope]

Originally Posted by DarinMartell

It's cold, it's snowing, and I have cabin fever so I am spending ALOT of time on ST. Problem is that I am spending so much time here I am getting the "I need new gear" itch. I have a old UK C6 that I like. Question is are any of the inxepenive ($30 or less) lights brighter or even just as bright but smaller?

I'm eagerly watching this thread, as I have the UK C6 on my shopping list at the moment...

[CODMAN]

Yes there definetly are... If you happen to have a Scubatoys 50$ gift certificate hanging around!!!!

Sorry, couldn,t help it!

But seriously... C6? Never heard of it! Are you talking about the SL6?

Anyways, 30$ isn't a lot of money.... But I can tell you this from experience! The new LED technology is remarkable! My SL4 eLed is brighter than my girlfriends regular C4. The SL4 e-Led is almost too bright for night diving in the caribean!

The LED technology is worth the investment in my oppinion....

[cummings66]

I love the LED technology, in fact after I get my tax return I'm buying the new Dive Rite 500 lumen led light.

[cbope]

Originally Posted by CODMAN

Yes there definetly are... If you happen to have a Scubatoys 50$ gift certificate hanging around!!!!

Sorry, couldn,t help it!

But seriously... C6? Never heard of it! Are you talking about the SL6?

Anyways, 30$ isn't a lot of money.... But I can tell you this from experience! The new LED technology is remarkable! My SL4 eLed is brighter than my girlfriends regular C4. The SL4 e-Led is almost too bright for night diving in the caribean!

The LED technology is worth the investment in my oppinion....

Is it a fact that LED lights are brighter? If it is, then why are the lumen ratings for LED lights so much lower than for traditional incandescents? I have a small dive light (unknown brand) that runs on 4 AA's. It has 3 LED's grouped together in the reflector plus an incandescent in the middle. I recently used it for the first time as a dive light, and in LED mode it was completely useless underwater. The incandescent was WAY brighter, even though out of the water the LED mode seems pretty bright. Due to my experience with this light, I haven't even considered LED dive lights. I know their advantages in the areas of battery life and ruggedness, but if they can't match a good quality xenon or similar incandescent bulb then I'm not interested. Especially since they are easily 2-3x the price for an LED equivalent.

Edit: Just checked the UK website and for example the SL4 non-LED light is rated for 113 lumens while the eLED version of the same light is rated for only 33-38 lumens.

[DarinMartell]

Sorry, yes it is a sl6 it takes 6 c batteries. I spent $30 for it and I like it, I am buying a light / strobe for a backup so I don't want to spend even more right now. But I see a-lot of lights in that $20 - $30 and was wondering if they worked better or as well if smaller.

[cummings66]

A lot of it depends on the technology in the Led. The color also makes a difference. I would guarantee you that my LED light at home would be brighter than all my lights save the HID if I could take it under water.

One possible reason for a LED seeming brighter than a regular bulb even though it has less lumens might have to do with the wavelength of the light being measured.

[No Misses]

Light propagation 101. Red is the first color to be filtered out by water. If you look at the Kelvin temperature of the light source, you will see that incandescent lights are heavily weighted to the red end of the spectrum (~3000-3200 K). LED lights are closer to the blue end of the spectrum. Manufacturers add phosphor to a blue LED to add some yellow to its emitted light. These higher frequency (shorter wavelength) colors will travel further in the water.

Color ------Wavelength (nm)
Red--------780 - 622
Orange ----622 - 597
Yellow-----597 - 577
Green------577 - 492
Blue--------492 - 455
Violet------455 – 390

The visible light spectrum (human) runs from ~390 – 725 nm

Note: Wavelength is inversely proportional to Frequency (high frequency = short wavelength, low frequency = long wavelength)

You can not convert degrees Kelvin to wavelength. Degrees Kelvin is a composite of wavelengths. Think of it as a grouping of colors that fall somewhere within the light spectrum. A high Kelvin number equates to the blue end of the spectrum and a low Kelvin temp would be on the red end of the spectrum.

Comparing an incandescent light’s lumen rating to an LED light’s lumen rating is like comparing apples and oranges.

Example: a 40 Lumen LED (~5000 K) would travel further through water than a 40 lumen incandescent (~3200 K), since the LED is more blue while the incandescent is more red.

An LED light produces most of its “energy” in the visible light spectrum. A typical incandescent light produces ~70 of its “energy” in the visible spectrum. The remaining 30% is in the infrared spectrum (heat). It is like a high powered car spinning its wheels. Only a portion of that power is actually usable.

Now with all of that being said, I still dive with a UK Sunlight D4 (204 lumens @ ~3200 K) and a UK Mini Q40 (50 lumens @~3200 K). Current LED lights are fairly bright. I believe that new developments in LED technology will make even brighter lights available in the near future. If I wanted a brighter light today, I would probably get an HID $$$.

I hope that I did not muddy the water too much. Good luck with your next purchase decision.

P.S. I think I pulled a frontal lobe, trying to get all of this information written down. :-)

[DarinMartell]

Originally Posted by No Misses

Light propagation 101. Red is the first color to be filtered out by water. If you look at the Kelvin temperature of the light source, you will see that incandescent lights are heavily weighted to the red end of the spectrum (~3000-3200 K). LED lights are closer to the blue end of the spectrum. Manufacturers add phosphor to a blue LED to add some yellow to its emitted light. These higher frequency (shorter wavelength) colors will travel further in the water.

Color ------Wavelength (nm)
Red--------780 - 622
Orange ----622 - 597
Yellow-----597 - 577
Green------577 - 492
Blue--------492 - 455
Violet------455 – 390

The visible light spectrum (human) runs from ~390 – 725 nm

Note: Wavelength is inversely proportional to Frequency (high frequency = short wavelength, low frequency = long wavelength)

You can not convert degrees Kelvin to wavelength. Degrees Kelvin is a composite of wavelengths. Think of it as a grouping of colors that fall somewhere within the light spectrum. A high Kelvin number equates to the blue end of the spectrum and a low Kelvin temp would be on the red end of the spectrum.

Comparing an incandescent light’s lumen rating to and LED light’s lumen rating is like comparing apples and oranges.

Example: a 40 Lumen LED (~5000 K) would travel further through water than a 40 lumen incandescent (~3200 K), since the LED is more blue while the incandescent is more red.

An LED light produces most of its “energy” in the visible light spectrum. A typical incandescent light produces ~70 of its “energy” in the visible spectrum. The remaining 30% is in the infrared spectrum (heat). It is like a high powered car spinning its wheels. Only a portion of that power is actually usable.

Now with all of that being said, I still dive with a UK Sunlight D4 (204 lumens @ ~3200 K) and a UK Mini Q40 (50 lumens @~3200 K). Current LED lights are fairly bright. I believe that new developments in LED technology will make even brighter lights available in the near future. If I wanted a brighter light today, I would probably get an HID $$$.

I hope that I did not muddy the water too much. Good luck with your next purchase decision.

Thanks for the lesson, so in English it means that if I want to spend less then $30 I am better off with the sl6?

Really, thanks for taking the time to share the science about it.

[CODMAN]

I honnestly don't know that much about the real reason the LED lights give better visibility underwater. I had always though it was a question of color/temperature, but anyways...

I'm being fully honnest here: the SL4eLED (38 lumnes) litterally blew away the C4 rated to 104 lumens. Really, in Roatan (80-100 foot day viz) it was almost too bright for night diving! I was using the edges of the beam so I wouldn't scare off too many critters. It's also way better during the day, in cracks and under ledges. I was litterally amazed....

Yes this model is more expensive than the regular sl6. But to be fully honnest with you, I think that investing 30$ on a sl6 is kind of throwing your money away... For 30$ more, you can get yourself the SL4eLED (and also the lamp will last much longer than the SL6; so integrate that into the cost) and you'll have no regrets...

This said, I also understand a budget. If you really can't afford it, choose the best you can within the budget! Or, if it's not urgent, put it off till you have the $$.

Also, if it's just for a backup, there is the Q40 mini eLED (I also have one) which is impressive.

Just trying to help!