# Emisar D4S review

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Carambas
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zeroflow wrote:
No, it is not linear as the curves for the 3×7135 and the FET are not linear but somewhere in the realm of x^3 which aims to achieve linear perceived brightness and not linear lumen.
ToyKeeper wrote:
In general, “visually linear” means the curve is roughly “x ** 3”. On the D4S though, if I recall correctly, I set the curve closer to “x ** 9” in order to provide more resolution in the lower levels.

I don’t understand what this mean: “x ** 3” and “x ** 9”. Could you understand me by using simple words?
How to count “ramp steps = lumens” for my future D4S Nichia 219C? Is there a formula?

ToyKeeper wrote:
If you want 50% power, that would be level 130 out of 150.

I want 1000 lumens. How could I get it? How many ramp steps is it?

ToyKeeper wrote:
Or, if you want ramp level 75, that would be about 300 lumens (roughly 3% or 4% of maximum power).

No. I would like about 1000 lumens on high ramp level.

Thanks you all for your help!

ToyKeeper
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Carambas wrote:
I don’t understand what this mean: “x ** 3” and “x ** 9”. Could you understand me by using simple words? How to count “ramp steps = lumens” for my future D4S Nichia 219C? Is there a formula?

That was the formula.

It’s not exact, but “x ** 9” is as close as one can get to a simple formula. It’s the shape of the graph used to calculate the ramp steps.

For more detail though, use the source, Luke. There is even a tool to calculate approximate ramp steps (in lumens).

Carambas wrote:
I want 1000 lumens. How could I get it? How many ramp steps is it?

The highest regulated output is ~400 lumens. Anything above that uses a direct-drive power circuit, so the lumens become far less precise. It may be 1000 lumens on a full battery, but with a mostly-empty battery it could be only 600.

However, if I use the ramp calculator command referenced in the link above, it tells me 1000 lumens is probably near level 105 or 106 on most models. But the 219C model has all the direct-drive power levels reduced to 80% of what they would be on other models, so it probably needs to go up to level 110 or so to reach 1000 lumens.

Those are all approximate though. To really find the exact level, you’ll need to measure the lumens.

Carambas
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ToyKeeper wrote:
use the source, Luke

You’re wrong! I’m not Luke. My name is Fernando P. Stefano.
DB Custom
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DB Custom
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Carambas, ToyKeeper is a Sorceress, Goddess of the Dark Side of the Moon, as such she knows The Force that Luke Skywalker used against Darth Vader (his father) in Star Wars. She was making a pun, use the SOURCE code , as in, May the force be with you, Luke Skywalker. Only, may the source be with you, Fernando!

Edit: I must’ve seen the original Star Wars 9 times when it first came out in ’77… loved that movie!

Andrew_Debbie
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x**y is how programmers write x to the power of y.

x**2 is x squared or x multiplied by x. Programmers write that as x * x.

x**3 is x cubed or x * x * x.

x ** 9 is. x*x*x*x*x*x*x*x*x
raccoon city
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I always liked x^y as x to the y, but I'm not a programmer.

Sillen
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Don’t know about D4S but I recently purchased Emisar D4 High Power LED Flashlight from Intl Outdoor Ordered 8th Sept, Shipped 19th Sept (should get it Monday next week)

Nealsgadgets purchased ROT66 and D4S at the same time Ordered 26th Aug, Shipped 30th Aug

Andrew_Debbie
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Pete7874 wrote:
Does anyone know how quickly Hank usually ships them out from the time you place your order?

Next day for me. My light arrived here in rural North Wales about 10 days after ordering. 10 days is unusually fast. < shrug >

I read in another post China will be on a national holiday the first week in October. You may run into delays because of that.

Pete7874
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Andrew_Debbie wrote:
Pete7874 wrote:
Does anyone know how quickly Hank usually ships them out from the time you place your order?

Next day for me.

Thanks. Mine has been sitting in “Processing” status for over 2 days now. My patience skills are weak.
jdh00
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Mountain just got a ton back in stock.

Andrew_Debbie
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raccoon city wrote:

I always liked x^y as x to the y, but I’m not a programmer.

One of the forgotten tounges, perhaps APL or even Forth used the caret ^ for exponentials.

Edit: No they don’t…-HP programable caculators used it too. x^y is on one of the keys.
-

scottb7862
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Pete7874 wrote:
Andrew_Debbie wrote:
Pete7874 wrote:
Does anyone know how quickly Hank usually ships them out from the time you place your order?

Next day for me.

Thanks. Mine has been sitting in “Processing” status for over 2 days now. My patience skills are weak.

Gotcha beat, 4 days now..ordered Sunday night…. first order too, sweating bullets here….
ToyKeeper
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raccoon city wrote:
I always liked x^y as x to the y, but I’m not a programmer.

The x^y notation is popular outside of programming. However, the ^ operator is a bitwise xor, so in a programming context x^y means “all the bits which are set in x or y, but not both”.

X  Y  X&YX|YX^Y
00000
01011
10011
11110

So I use x**y instead, because it doesn’t have that ambiguity.

mkdive
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Great lights! I have another xpl/blue aux inbound now.

Andrew_Debbie
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I was wrong about APL. APL uses a single star symbol. x⋆y. This is unicode 22C6 and not an asterisk ‘*’. ⋆x in APL is e**x.

Forth uses f**

BASIC uses ^

https://www3.rocketsoftware.com/rocketd3/support/documentation/d3nt/91/r...

https://docs.intersystems.com/latest/csp/docbook/DocBook.UI.Page.cls?KEY...

raccoon city
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Andrew_Debbie wrote:

BASIC uses ^

Ah, and I only learned Commodore BASIC...

So that must be it.

Tom Tom
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Andrew_Debbie wrote:
Edit: No they don’t…-HP programable caculators used it too. x^y is on one of the keys. -

That’s pretty much standard on good calculators (HP, Ti, Casio)

I use x^y too, and grew up with HP programmable calculators. Reverse Polish, and the Stack. They seem so natural to me.

Also the standard for finance/accountancy. Don’t trust a beancounter unless they own an HP and are completely familiar with it (i.e. don’t even need to look at it, whilst operating, it’s just an extension of their hand.)

Of course, the concept of owning a calculator is nowadays as archaic as owning a slide-rule, or a sextant for navigation. There is always an app instead. But I’m old-fashioned and have a small collection.

https://en.wikipedia.org/wiki/Reverse_Polish_notation

Andrew_Debbie
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RPN jogged my memory. dc uses ^

From the man page:

^ Pops two values and exponentiates, using the first value popped as the exponent and the second popped as the base. The fraction part of the exponent is ignored. The precision value specifies the number of fraction digits in the result.

Quick test on Ubuntu 18.04:

~\$ dc
5 3 ^ p
125

ToyKeeper
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I still have a HP48GX in nearly-new condition. That doesn’t mean it hasn’t been used though… just that I’ve taken good care of it. For a long time I had it thoroughly loaded up with programs (er, user RPN scripts) I made. Unfortunately though, it later lost everything I had installed, and I didn’t have a good backup.

Since I liked it so much, I also made my own RPN-based calculator, for use on my Linux PDA. I never got around to giving it functions for graphing or symbolic algebra, but it was still a handy thing to have around for more basic functions.

Andrew_Debbie
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I use my HP11C daily. I’ve had it since new. Serial is 2633Axxxxx or 1986, week 33, made in USA.

alchemi
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We should really start a calculator thread… but

This is what I used in school — count them digits!

Later I had an HP-15C — a lovely calculator. I sold it on e-bay some years ago because I was not using it, and it needed to go somewhere where it would be appreciated more. My mobile has some RPN calculators on it, even some the look like the HP-15C, but I don’t use calculators these days and instead fire up Excel even for simple tasks.

Back on topic: I’ve ordered the D4S with Neutral White – XP-L HI V2 5D, 4000K .

sbslider
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Andrew_Debbie wrote:
I use my HP11C daily. I’ve had it since new. Serial is 2633Axxxxx or 1986, week 33, made in USA.

Looks very much like my 15C on my desk at work. I used it once or twice a year for some calculations. The display has a black area at the bottom, but it still works just fine. Can’t remember the last time I changed batteries, must be over 20 years ago.

PocketSammich wrote: I don’t need this, but I want it. Please sign me up.

DB Custom
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I was a geek on the pocket calculators when they first came out. The LED’s would eat up cells in no time! I was all about the smallest, tiniest calculator I could find. My Aunt bought me one that was like two pens, it opened down the length to show the keyboard on one side and display/battery compartment on the other. Sharp I believe it was. One of my first LCD models.

Studied Cobol in college, and keypunch. Dropped it due to heartbreak caused by a certain blue eyed wonder that loved acting, especially enticing me with a British accent…. ironically enough (and I don’t think I ever even realized this) her initials were also DB. lol [circa 1980]

ssschen
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Are there any photos of the blue aux lights?

ssschen
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minim
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Just found this awesome forum after shopping for som flashlights. I live in Norway with long dark winter nights and I’ve used some old cheap bulb-flashlights until recently when I found a Nightcore HC-60 and discovered how nice these 18650 led lights could be.

I have now placed an order for Emisar D4, Convoy S2 (+ diffusor for lantern usage at power drop) and a Astrolux MF02S. I totally lost it for cool flashlights so even now without any of these in my hand due to slow shipping I looking at new ones.. Just discovered this D4S and regret that I didn’t get that instead of the D4.. Is it a big difference so I need both? Might be the wrong place to ask such a question

Maxabeam - Astrolux MF02S + MF04 - Emisar D4s - Emisar D4 - Convoy S2

komeko
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Welcome to the forum
Do not worry at all that you ordered D4 because you will buy D4S and many other flashlights anyway

Click on:        ANSI WHITE

Click on:        MY COLLECTION

Click on:        Q8, D4, D4S, D18, K1, FW3A, SDmini, Mini AAA, TIP, M43, H1, H03, TC20, TN40S, TN42, V6, H600Fw, SC600w, SC64w

Newlumen
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minim wrote:
Just found this awesome forum after shopping for som flashlights. I live in Norway with long dark winter nights and I’ve used some old cheap bulb-flashlights until recently when I found a Nightcore HC-60 and discovered how nice these 18650 led lights could be.

I have now placed an order for Emisar D4, Convoy S2 (+ diffusor for lantern usage at power drop) and a Astrolux MF02S. I totally lost it for cool flashlights so even now without any of these in my hand due to slow shipping I just discovered this D4S and regret that I didn’t get that instead of the D4.. Is it a big difference so I need both? Might be the wrong place to ask such a question

D4 is actually good for edc and many 18650 are easily available for that light. \$35 is even better price..

D4s is big step, bigger, brighter, aux led, and improved throw..

Pete7874
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scottb7862 wrote:
Pete7874 wrote:
Andrew_Debbie wrote:
Pete7874 wrote:
Does anyone know how quickly Hank usually ships them out from the time you place your order?

Next day for me.

Thanks. Mine has been sitting in “Processing” status for over 2 days now. My patience skills are weak.

Gotcha beat, 4 days now..ordered Sunday night…. first order too, sweating bullets here….

I got impatient, so I ended up ordering from Richard instead.