yes you’re right the emisar d4s is better because it lights as well as blf q8 and especially i can choose the tint i want. But i want to know:
will it become so hot that i will not be able to hold it in my hand anymore? in this case will it be security by automatically lowering the brightness?
-Is she able to light for about 3 hours? if yes how many lumens please?
Thank you for your answers
Preposterous question. That’s like saying “I’ve decided to start maintaining my house, please suggest a tool that can do everything”. A hammer is a great tool, until you run into a Philips screw, or a 10MM bolt…then your hammer is useless. Likewise, I strongly recommend the #2 Philips screwdriver…but that won’t do anything for you if you run into a nail, or need to cut a piece of wood.
There is no single flashlight that’s going to do everything….particularly under the laundry list of demands you’ve outlined in the top post, and low price you specify.
Both light are very bright, max lumen are similar 4000 for the Emisar D4S with sst-20, 5000 lumen for the Blf Q8 that's not a big difference, the D4S will generate heat quicker cause it is smaller, but it's only need one battery and it is a very versatile flashlight very light and easy to carry. The auxiliary led on the emisar are cool too. 
If you don't mind the weight the BLF Q8 is a very nice light too just bigger and heavier, therefor it handle the heat better.
If you need something versatile and powerfull, ready for every situation i'll choose the emisar D4S
If you need autonomy/run time and less heat in your hand then the Blf Q8 is the one.
As i said there is many other cool flashlight around there, wait for more comments, watch some videos you'll have a better idea of what you want/need. but those 2 worth exploring.
thanks for the Sofirn Q8 
I went to see, yes she is exactly like blf q8
I have questions:
teacher thank you for your message and indication on sofirn Q8, but i do not understand what you told me: CCT. What is CCT? Virisenox
you told me:
the sofirn Q8 has the body tube (no flats)
I do not understand what it means … Can you send me a link or a picture to show me a body tube flashlight no flats please?is it not so good?
the sofirn Q8 has led XP-L HI while blf Q8 led XP-L HD V6 3D
I would like to know which of these 2 led gives the most lumens?
what i like more @Virisenox is that you tell me that the sofirn Q8 is 6000K-6500K while blf Q8 than 4500-5000k so i think the light will be more beautiful with sofirn Q8, can you me to confirm ?
Not sure why you think that you need 6000K tint for this. 6000K is cool white. Most people on here would probably suggest neutral white (5000K) instead, but I guess it’s personal preference.
D4S has thermal regulation, and the max temp is user configurable, so you can set it to whatever you think you can handle.
CCT is correlated color temperature, often just shortened to color temperature. Higher is more blue. Lower is more yellow.
Flats are parts of the battery tube that are ground flat instead of rounded. This doesn’t provide any meaningful objective advantage or disadvantage.
The XP-L HD produces more lumens than the XP-L HI. The XP-L HI produces more candela (throw / beam distance) than the XP-L HD.
Which color temperature is “more beautiful” is a matter of opinion. In the opinion of the average BLF member, 5000K is preferable to any other option, and very preferable to 6500K.
Nope. Just like multiplying 2 negative numbers, they cancel out each other.
I tried blowing smoke-rings with a cigar, and sticking the light through them, but couldn’t get any rings to “stick”.
could I have your opinion on these flashlights? are they less good than those you have advised me? :
https://www.fasttech.com/product/9661322-authentic-ultrafire-uf-a28-led-flashlight
Lumintop ODF30
Astrolux MF01
https://www.amazon.com/Powerful-Flashlight-12xLEDs-Rechargeable-Batteries/dp/B07F3VW2WP/ref=as_li_ss_tl?tag=shopperz_origin3-20&ascsubtag=317610217-2-&SubscriptionId=AKIAJO7E5OLQ67NVPFZA
https://www.amazon.com/Brightex-Tactical-Flashlight-Resistant-Protected/dp/B07D5GBN8W
convoy L6 ?
Anything from Ultrafire, the Brightex zoomie, and the no-name 12 emitter light are objectively less good than a BLF Q8. They are most likely lying about their performance, poorly built, and possibly a fire hazard with poor quality included batteries. The others are different.
The Catapult is a compact dedicated thrower. It has a much more focused beam, much less output, much smaller battery capacity, USB charging, and a much smaller overall size and weight.
The ODF30, and the similar Thrunite TC20 are fairly floody lights otherwise similar in design to the Catapult.
The MF01 is a large, floody light similar to the Noctigon Meteor. I expect better build quality from the Meteor. In either case, the Nichia 219C option has a high color rendering index for more sunlight-like light.
I thank you for these explanations
I am surprised to see all the great features of the DS4 and also for the security is very good
in fact, that’s why i prefer the 6000K, because i have this led projector that is 6000K :
http://image.noelshack.com/fichiers/2019/02/7/1547340615-22039227.jpg
and when i turn it on at night with, it’s a pure white i like … but you probably all right here because you are much more expert than me, and the 5000K must be better. i will choose 5000K and listen to you
Thank you very much for these very technical explanations i will write down everything you just wrote to me to remind me
5000K is a warmer light than 6000K. In my opinion 5000K is like very, very warm sunlight like you have in the morning or evening. 6000 to me feels more like high noon with a cloudy sky. It really is just a matter of personal taste. I for example am one of the people who prefer 6000K over 5000K in a flashlight. Not as the main light in my living room, but for my work light.
I think the D4S is a very good choice and so is the Sofir/BLF. What you have to understand though is, that LEDs emit heat when run on full power. The bigger your flashlight is, the better it can transport the heat away and the longer you will be able to use on a very high brightness without it getting burning hot. In reality just about EVERY modern flashlight won’t be able to be used in the brightest mode (usually called “Turbo”) for more than a couple of minutes. For some it is even only seconds. So if you don’t mind weight at all but only need high output for extended periods of time it usually is a good idea to go for the biggest light you can. And forget about those “super bright” lights on Amazon, Ebay or local stores that nobody ever heard of anywhere else and where you can find no reviews of. They are lying about the output 99% of the time.
finally sofirn Q8 is an evolution of blf Q8? he is a little better then? But you advise me to buy even better by taking the emisar d4s which will be the best choice? if so i will buy it with the link you gave me:
https://intl-outdoor.com/emisar-d4s-26650-high-power-led-flashlight-p-932.html
but there are things that i do not understand in the link:
what do you mean this? :
Aux LED :
Cyan (by default)
Amber
Green
Red
and what’s the use of Magnet in the tailcap?
under: Led & Tint
What is the best for you that i should check? If i have to add 15 dollars i’m ready to add if it’s really better?
I am a little disappointed because there is no battery delivered with 
what is the best battery i will have to buy? I’ll take 2 because you told me that the lighting lasts less than the blf Q8 …
I thank you for your expertise and have analyzed the models i quoted
There isnt such thing as the perfect flashlight. The blf q8 has very good output with around 5000 lumen and nice throw and flood. And it handles the heat pretty well.
Maybe you can specify more what you would like from a flashlight?
EDIT after reading you @kanton, and thank you for teaching me to avoid flashlight “no name” or unknown on amazon, ebay and others of the same kind where they lie fortunately i knew your forum by luck thanks to a person on a forum who advised me your budgetlight forum
so after reading you too, i hesitated again now between sofirn Q8 and emisar ds4 … i do not know what to do …
For maximum capacity and low heat, I would just get the Sofirn Q8.
You can leave a message with your BLF username in the Aliexpress order to get a discount down to 40$US if I remember well.
Ah gotlib, you have started down the path of no return to ……. Flashaholicandia. Most of us are there already. You will recognize us when you get there: We have BOTH the G4S and BLF Q8. And we have many, MANY other lights. Beware!
To answer your questions above:
The Sofirn/BLF Q8 is available at: https://www.amazon.com/Powerful-Flashlight-Professional-Searchlight-Upgraded/dp/B07GR2HM2Y
The Thorfire/BLF Q8 (the original Q8) is at BLF Q8 5000lm Super Bright 4xled Tactical Flashlight Multiple Operation Torch for sale online | eBay
None of these come with batteries. Few flashlights do. Therefore factor on adding the price of 4 batteries. Batteries for this light are 18650 cells that are Button-top/Hi drain/Unprotected. There are a zillion opinions about which batteries are best (Samsung, Sony, Panasonic, LG……) I’m not going to venture an opinion. 
You have the best link for the D4S. The Aux LED is a decorative very, very dim set of LEDs that stay on most of the time. They come in the colors you list. Photos of these are at the website you have. They look cool and make finding your flashlight easier in the dark.
If you decide to order the D4S, order two of the batteries offered on the same page. Simple. Can’t go wrong.
The Magnet in the tailcap is exactly that: A very strong magnet that lets you stick the light to a metal surface. This is handy if you work on the engine of your car. Attach the light to the open hood.
LED and Tint: Based upon how you describe your use of a light and your color (tint) preference, I believe you will be happiest with the SST20 5000K. The SST20 5000K throws a beam farther than the XP-L HI V2 3A 5000K and saves you $15. I don’t think you will be happy with the SST20 6500K as too much color is lost.
Thank you very much for your very complete answer to my questions and all your links, it’s really nice!
Just before reading your answer, i had read the one from: Polarweis just above,that i also thank, and i had an idea that i had already had several weeks ago! : watch youtube videos! So i typed: blf q8 vs sofirn q8
and there are several videos!
I saw this one:
but i’m not sure that sofirn in the video is first? Can someone confirm me?
if sofirn is first, she totally convinced me packed! we see immediately what lights further and has more lumens, the lighting is stronger and in + the light is whiter more beautiful thanks to leds XPL HI! it is better than blf q8, it is not for nothing if it is a little more expensive;)
I read the comments of this video and a person is talking about: ThorFire S70S
I then looked at the specifications of the ThorFire S70S, which seems pretty good to me, it has the led XHP70 and illuminates 3h45min to 1800lumens which is huge and 55min in turbo has 3960 lumens and 87000 candela, throw very far , but it is also more expensive, unless i can find it with a coupon code but i doubt …