I received a new Emisar D4S today. Thank you Hank.
This is my second D4S.
My first D4S has XP-L HI V2 3A (5000K) emitters. In the photo below, it is the gray light on the top.
The second one has SST-20 (5000K) emitters. In the photo, it is the green light in the middle.
I will identify the third light and its purpose here in a moment.
I offered to share comparisons of the beams of the two D4S in order to observe:
- Beam cross sections: Are the beam cross sections different? I.e.: Is the SST-20 beam narrower, more focused than the XP-L HI – hence making it a somewhat throwier light?
- Tints: Are the tints of the two lights similar; the emitters of both are described as being 5,000K.
Below are shots of the two D4S’ beams on my ceiling. The two lights were stood on their tails on a desk, pointed at the ceiling five feet above. The photos were taken with my iPhone 7 that lay on the desk next to the lights.
The third light above, the one at the bottom, is an Emisar D1S – a dedicated thrower. I have included it for reference: Its beam cross section is decidedly narrow and focused as it is designed to be a thrower.
About the three ceiling shots:
The first is of all three lights DIM - near the bottom of their ramping range.
The second is of the two D4S near the MIDDLE of their ramping range. This is an estimated middle point.
The third is of the two D4S at full TURBO, the photo taken within three seconds of simultaneously starting turbo on both lights.
The iPhone did make exposure adjustments that brightened the first photo and dimmed the turbo shot. These adjustments did not affect the representation of beam cross-sections, relative brightness of the two D4S to each other or their respective tints.
Both D4S lights had freshly and fully charged, identical, hi-drain, unprotected 26650 cells. Neither DS4 has been physically modified nor have their UI programs been adjusted.
What do you observe?
My observations:
- Tint: There is obvious tint change as the two D4S ramp up. They are different at low level but become very similar as they brighten. The XP-L HI V2 3A is ever so slightly pinker. The SST-20 is ever so slightly yellower.
- Beam cross-section: I don’t see much difference between the two D4S lights. Maybe the SST-20 has a slightly more defined hot spot at turbo level. Maybe.
I took both lights outside last night and very unscientifically compared their illumination down a long tree-lined road. I could not tell much difference in throw, flood or tint (when ramped up bright).
Beyond the first five minutes of turbo:
One difference between the two lights the photos don’t show: The XP-L HI V2 3A runs hotter than the SST-20.
As both automatically ramped down due to their high temperatures, the tint difference became more pronounced: The XP-L HI V2 3A relatively whiter/pinker than the relatively yellower SST-20.
For the next 60 minutes, the XP-L HI V2 3A stayed noticeably brighter even as it continued to run much hotter – too hot to hold without a glove. The SST-20 dimmed lower more and stayed a bit cooler – just cool enough to hold barehanded.
At 90 minutes the D4S with the hotter XP-L HI V2 3A emitters started to fade quickly – its battery largely spent. The cooler SST-20 D4S held on to useful light until about the two-hour mark when it too faded - though slowly.
10 hours after both lights had been switched to turbo, they were both putting out enough light to read by; a lumen or two.