Emisar D4S review

In this very thread. Start reading from here:

thanks a lot, i’ve flashed many attiny13a but never tried with a tiny85, that post is a big help

Very interesting, thanks d_t_a! :beer:

I just measured the D4S with SST-20 3000k 95CRI at 2,328 lumens at 1s with my TA Lumen Tube. It is less rosy than the 3000k HD2 tinted emitters from Kaidomain and the SST20 3000k used in the NS22. It might be due to the optics. The XP-L HI v2 version measures about 3,577 lumens at turn on.

Also previously I read someone posted Hank said the 3000k is J4 flux bin but the spec sheet only shows it going up to J3 so not sure if Hank got a special batch or if the J4 was a mistake.

I have this exact light (well, it’s twin). You will love it. I had green Nichia also, until my wife commandeered it.

How much does D4S weigh?

Together with the battery, it weighs 223 grams.

Thanks komeko. Which battery was that?

Lii50 black

Until my 26650 cell arrives I’m using a Samsung 30Q held securely in place with foam. Weight is 176g. Feels good but very slightly unbalanced.

So about 127-128g empty. Thanks!

129g :+1:

Edit: that’s with a standard tailcap, i.e. no magnet

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:

  1. 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?
  2. 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:

  1. 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.
  2. 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.

Are the two lights set at the same temperature?

Oh man that is a very nice comparison!
Since i ordered mine with SST-20 5k i was looking for this kind of information, but this emitter option is still pretty recent so there is not much information/comparison between those 2 in the D4S.

After a lot of reading i was under the assumption that the XP-l HI will be more efficient, therefore will generate less heat but maybe i'm wrong.



I'm curious to know if the default thermal configuration settings are the same on both light, maybe they sent the sst-20 with a different default setting, that could explain the longer run time and the quicker step down, if anyone have some clues about that it would be nice to know.



Wich battery did you use inside both light?


last but not least,i would have a request if it's possible?

Could you test with an ir thermometer ( if you own one ) the temperature of the head on both light and the duration before the turbo step down, with the same thermal configuration setting on both lights for an accurate reading?

If you can do that, you'll be the Man!

I know it's a lot to ask but we don't have this kind of information and i think it's could be really really useful for the community and for potential buyer, i think you'll be the first one to do it and i will deeply appreciate it.

Anyway, let me know if it's possible and thank you very much for your comparison!

The sst20 in your pictures looks green , is this because of the camera or did you notice the green by eye?

Good question. I don’t know the answer. I left both lights in their default settings as delivered. From reading others’ posts in this thread, I believe they can be modified to change the temperature step down. I’m not sure which way I would want to modify: Reduce the step down temperature of the XP-L HI V2 3A so it doesn’t get so hot in the hands? Or raise the step down temperature of the SST-20 so it stays brighter longer? I probably won’t do the former, choosing instead to regulate the temperature simply by ramping down.

Regarding the batteries: They are both Orbtronics, reputable rewraps sold as being 30 amp pulse; 22 amp sustainable until 80C after which they presumably throttle back. The SST-20 never felt that hot. The XP-L HI V2 3A must have been close. 5,750 mAh each.

Spideroz - I’m afraid I am going to flunk out at being the man. I don’t have any testing equipment. :frowning: Just my watch, my eyes and burnt hands! :slight_smile: The moment of step down for each light is hard to detect as changes are very smooth - no flickering. It looked to me that there were several minutes (how’s that for precision) of full-out turbo for both - before I could tell the SST-20 had eased back. The XP-L HI probably was ramping down somewhat after those same few minutes - but more slowly.

Mostly its the camera. To my eyes, at high brightness, both emitters look about the same color - a neutral white - no greenishness. As the SST-20 gets dimmer (maybe below 1,000 lumens?) it is yellower - but I would not describe it as being greenish.

@Frumious

Ok i had to ask, worth a shot.

Subjectively speaking witch one do prefer if you have a favorite?

Anyway thanks for your feedback man. :THUMBS-UP: