I haven't been here in ages, but wanted to share a prototype project I just completed where I replaced the old 50W halogen bulb in one of my Ikelite Pro Video Light II heads with a pair of state of the art CREE MC-E neutral white LEDs. The lumen power of the LEDs at 20W is comparable with the old halogen at 50W, but the white is near sunlight color at 5000k vs 3200k yellowish of the halogen. With the halogens, I used to use CTB filters for balanced light work losing about 2 stops of light power. Those days are over. I also get 5 power levels at the same color temp and some protections features from the smart boost power supply. Testing results look promising, and I'll be diving with it for the first time later this week. I put up a short slide show video on YouTube showing some steps of the conversion and a comparison of a converted head versus the original one. You can see it here:
Brian D.
I haven't been here in ages, but wanted to share a prototype project I just completed where I replaced the old 50W halogen bulb in one of my Ikelite Pro Video Light II heads with a pair of state of the art CREE MC-E neutral white LEDs. The lumen power of the LEDs at 20W is comparable with the old halogen at 50W, but the white is near sunlight color at 5000k vs 3200k yellowish of the halogen. With the halogens, I used to use CTB filters for balanced light work losing about 2 stops of light power. Those days are over. I also get 5 power levels at the same color temp and some protections features from the smart boost power supply. Testing results look promising, and I'll be diving with it for the first time later this week. I put up a short slide show video on YouTube showing some steps of the conversion and a comparison of a converted head versus the original one. You can see it here:
Brian D.
I'm looking forward to hearing about your results.
What is the CRI of those LEDs?
--Mark
I'm looking forward to hearing about your results.
What is the CRI of those LEDs?
--Mark
Spec says 75-80. Not sure I buy into the CRI hype myself, as the results with a particular camera and white bal settings are going to add more variables making CRI subjective for the practical sense. I consider it a 'ball park' rating.
For now, I've done some testing in a cavern. The results are very good. The 110 degree beam angle of the chip's native optics give me uniform coverage with zero hot spots. What I have yet to do is test balanced light shots (with sunlight), which is my critical use case. I will update with results when I have those. I will also do some testing with the amphibico calibration slate.
That's pretty cool, what is the cost of the LED's?
That's pretty cool, what is the cost of the LED's?
You need more than just the LED chips. The chips have 4 LED elements in them, and cost me about $28 each mounted on metal backed star PCBs. Each head has two LED chips (8 elements.) I then have some circuitry for control power (5 levels of power) and protection (cut off on overtemp and over discharge of battery.) I may have about $125 worth of parts in each head.
I'm looking forward to hearing about your results.
What is the CRI of those LEDs?
--Mark
Ok. I just got back after making 7 dives on a wreck 60 miles out in the Gulf of Mexico in 115 fsw. I shot about 1 hour of video on my HC7 using my prototype CREE LED heads. I also did a couple shots with the GoPro hero w/ and w/o lights at 115fsw. Since my HC7 in my USVH housing doesn't allow for manual white balance underwater, I usually just fix my white balance at 'outdoor' during daylight dives and then correct my footage in post. I just put up some raw images in my latest gallery which are simple frame grabs from the HD video. I used no color correcting filters while shooting and then only post processing done for these test images was deinterlace and resize. Overall, I'm very pleased with the results. The light color temp is consistent at various power levels and my batteries never drained low enough to hit the shutdown threshold even after three 42 min dives on day one. Please check out my latest gallery for the LED test result frame grabs. I will get some video up soon.
Here is some night dive video I shot with these self-built CREE heads at 70% power. I find if I run them at 100% for more than 5-7 min continuous, I get an over-temp issue with the driver circuit protecting itself and dropping the power automatically. The camera is a HC7 in an USVH with the WB locked at built-in *daylight* color temp preset.
