ReviewTheLight: Fenix LD50 (Double-Barrel, 1800 Lumens)

Bigmac_79

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Fenix is one of the most well-respected names in the high-end flashlight industry. They've got a wide range of flashlights of all types and sizes, but the LD50 is a bit different than most. It's flat profile and ability to drive two XM-L2 emitters, each from a separate battery, make it a light that can fulfill a unique niche. Presenting, the LD50:


Thanks to Fenix for providing the LD50 for review.


I’ll be reviewing the LD50 in two sections: first, I’ll discuss the light objectively (the facts about the light itself), then I’ll discuss the light subjectively (my impressions about the light's performance when used for specific applications). If you have any other specific applications you'd like the light tested for, let me know and I'll see what I can do.

Video Review

Below is a video review of the LD50. Due to my old image hosting site closing down, I've got new restrictions on image uploads and have replaced the "Construction" section of my reviews with a more detailed video review.


This video is available in 1080p HD, but defaults to a lower quality. To select the playback quality click the settings button (looks like a gear) after you've started the video.


Objective

Manufacturer's Specifications

Price: 120 USD





Product Manual




Dimensions




Plus, here's a few shots with some good detail.









th_IMG_6654.jpg
th_IMG_6655.jpg




User Interface

The LD50 is basically two independent flashlights, stuck together and controlled by the same button. The side switch controls the five brightness modes and the Strobe mode.

To turn the light on, hold the button for about half a second, and the light will turn on in the last brightness mode you used. A quick press will cycle you through to the next brightness mode in the sequence Eco -> Low -> Mid -> High -> Turbo. Holding the button again for half a second will turn the light off.

If the light is off, holding the button for a full second will first turn the light on (at the half second mark), then turn it to Strobe (at the one second mark). Pressing the button again will turn the light back off.

If the light is on, holding the button for a full second will first turn the light off (at the half second mark), then turn it to Strobe (at the one second mark). Pressing the button again will turn the light back to the last brightness mode you were using.

Because the two sides are driven independently, either side will operate if the battery in the other side dies or is removed, or if one side is somehow damage. However, they are controlled by the same circuitry, so the two sides will always be at the mode setting. The only exception to this would be if the battery on one side was more depleted than the other, and when using a high output mode the more depleted battery was unable to supply the necessary current, resulting in one side dimmer than the other.

Action Shots

You can click on any of these shots to see them full size.

Light in Hand


MugShot


BeamSlice


White Wall
ISO 100, f/3.5, 1/20"


Indoor Shots
ISO 100, f/3.5, 1"
(Eco mode shot missing)

Outdoor Shots

ISO 100, f/3.5, 2.5"




Performance

Submersion: I submersed the LD50 under a foot of water for about an hour, clicking the switch several times. I found no evidence of water entering or damaging the light.

Heat: The LD50 gets warm after only a few minutes on Turbo, and is very hot by the end of the 10 minute pre-stepdown period. If you intend to force it back in to Turbo after the stepdown, you'll want to be using some method of cooling it (cold environment, hand directly on head to soak heat, etc.).

PWM: I could detect no pulse width modulation on any mode of the LD50.

Drop: I dropped the LD50 from about a meter onto various surfaces (including grass, carpet, dirt, and hard wood), and found no cosmetic or functional damage.

Reverse Polarity Protection: The LD50 claims reverse polarity protection, so I tried putting the battery in backwards and pressing the switch, then correcting the battery. I found no evidence of damage from the reversed polarity.

Over-Discharge Protection: The LD50 will begin to decrease in output, and flash a few times every few minutes when the batteries get low, so that's your signal to recharge or replace when using lions.


Spectral Analysis


All light that we see as white is actually made up of several different colors put together. The relative intensities of the different colors in the mix are what determine the tint of the white we see. For example, cool white LED's have a lot of blue, and warm white LED's have more red or yellow. This measurement was done on a home made spectrometer. The plot below the picture is corrected for the spectral sensitivity of the human eye. Note: the peak in the 900nm region doesn't really exist, it's a piece of the second-order spectrum that's showing up here because of the high intensity of the light source.

Output and Runtime


ANSI FL-1 runtime ratings are the time it takes for a light to fall to 10% of it's original output (counting from 30 seconds after turning the light on).

The vertical axis of the graphs below represents a relative brightness measurement using a home made light box. The horizontal axis is time in hours:minutes:seconds. Runtimes are stated in hours:minutes:seconds. These graphs may be truncated to show detail.

Mode Comparison


Turbo



High




Throwing Distance

ANSI FL-1 standard for stating a light's throwing distance is the distance at which the peak beam intensity (usually at the center of the beam) is 0.25 lux. I calculate throwing distance and candela (lux at 1 meter) by measuring peak beam intensity at five different distances and using the formula lux*distance^2=constant.





Subjective Review

Quick break down:

+ Compact & Slim
+ High output
+ Great regulation
+ Battery options
+ Independently driven emitters
+ Single switch - simple UI
+ Electronic lockout
+ Firm clip, screwed on
+ Beams converge nicely
+ Separate reflector for each emitter
+ Unique look

- No hard lockout
- Eco mode could be lower

In the review of the LD50, it's been obvious to me that as Fenix has grown confident with traditional design flashlights, they have room to be bold with some more unique ideas. In the LD50, I think they've really hit on something here, because this is now the brightest light I have that I would carry in my pocket regularly.

There is some ambiguity in the term EDC, which stands for Every Day Carry. Essentially there are many lights I Carry at some point Every Day: the AAA light on my keychain, the headlamp I use for nighttime chores, the 3x18650 I keep in my work bag, the big thrower I keep in my car, etc. But the real deal is the light I keep clipped in my pocket at all times. Usually my all-the-time pocket light is a single AA light with control ring, because 200 lumens is all I need for most general tasks that come up, and I like how small it is. At this time, I don't have any regular tasks that really call for more than 200 lumens, but if I know I'll be needing something more powerful I'll swap in a 1x18650 light for my pocket carry, for the extra run time and output. These single-emitter single-battery lights are getting pretty powerful, with 800-900 lumens becoming widely available in slim forms, and up to ~1000 lumens for some of the chunkier models. If I thought I'd need any more output than that (or more runtime than a single 18650 could give at those levels) then I'd grab a large 3x18650 light and clip it's holster to my belt or put it in my bag. Now, the LD50 has opened up another option. This light is slim enough that I'd be happy carrying it in a pocket all day/night without, and with two emitters and two batteries I get almost double the output or run time that I would from a single 18650 powered light. I'm really happy with how this worked out, and I hope we see more lights taking these sorts of innovative approaches to getting high output from an even more compact light).

Next, the output regulation of the LD50 is just great. You can look at the graphs yourself (above), but basically this what I like to see: very small drop in output at the start, flat output for the majority of the run, and a drop or curve down to a very low level of light that you can use to get new batteries or a new light in you hand. On Turbo mode, the LD50 does just what I expect from a mode labeled "Turbo" - maximum output for a short time, with a drop down to a sustainable output after that. For the most part I like the mode spacing, but I do wish that the Eco mode was more like 10 lumens, so I could drop it to 5 with only a single emitter running--this would increase run time and make this light even more versatile for regular pocket carry.

Speaking of using only a single emitter, that brings us to my next big + about the LD50: it's two emitters are driven independently but controlled by a single switch. With the independently driven emitters, you don't have to worry about matching battery voltage or even battery chemistry, which makes this light extremely versatile--I can just grab any 18650 or CR123 batteries out of my drawer and pop them in. If I don't have enough batteries on hand to power both sides, I can run just a single side alone. Obviously, if I intended to run just a single side most of the time, it would make more sense to get a single emitter light, but having this option makes the LD50 a great choice for an all-situations backup or emergency light. This feature also effectively doubles the output levels I have available to choose from. Unfortunately, this brings me to the one real drawback I've found on the LD50: it lacks a hard (physical) lockout mode. The side switch of the LD50 looks cool and is very comfortable to use, but being located on the side with so little protection, it can easily get bumped in a pocket or bag, especially when not in the holster. The holster adds some protection, but the button can still be pressed from within the holster. There is an electronic lockout available, but it is deactivated by holding the button for a few seconds, which while is less likely in a pocket or bag than a quick bump, is still a possible accidental event. You can read the comments below for some discussion about the possible reasons why this choice may have been made, but by leaving the threads on the tail caps un-anodized, the LD50 lacks a hard lockout option, which would have been a great advantage in my opinion, especially in this situation with the independently driven emitters.

A few other little things about the LD50: The clip is good. I've gotten several questions about it, and trust me, it's got a lot of holding power but is still easy to slip on to a pocket, belt, etc. The way they've designed it, the majority of the clip is above the plane of the light's body, but near the end is a dip that goes down into the groove between the body sections, which will be the contact point for the clip (it's a great integration of design features). The beams converge nicely, which means they're well aligned, which is even more impressive than usual considering their separation. Their separation also means that each beam get's it's own full reflector, with no cutouts to share sections with other emitters, so each has the maximum of it's light gathered and directed into the beam. Finally, they looks of the light (the contrast of the switch button and clip with the black light body in particular) make this look like a pretty classy light.

Overall, the LD50 is an excellent light that seems to create a new niche for itself - the multi-emitter pocket light. This is the brightest light I've reviewed that I considered to be continuously pocketable, and by a significant margin. If you're preparing to pack a punch with your pocket light, the LD50 is likely one of the best options you'll find.

Long Term Impressions
I'll fill this part in after carrying the light for a while. If nothing get's added here, either I find nothing else worth noting about the light, or I end up not using it often.
 
Last edited:

Taz80

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Thank you for the review, very nice. This is an interesting light, high output in a very compact package. The 10 minute step down is good for this size light. Now if only....................oh well its still a neat light.
 

jmsodpc

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i got mine today and its super nice. i like the flat grippy style and the double barrel lights that converge into a single hotspot of bright white light.
 

moshow9

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Nice review Bigmac_79! In your video you mention the LD50 has a sort of soft lockout, in that it requires the button to be pressed about a half second in order for it to turn on (longer than that puts it in strobe from off).

How much pressure is required to press the button? If one wanted to throw this in a pack, either in it's case or without, is there a possibility of accidental activation? From your video, it does not look like a hard lockout is possible when you were replacing the second 18650 while the light was on.
 

Bigmac_79

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Thank you for the review, very nice. This is an interesting light, high output in a very compact package. The 10 minute step down is good for this size light. Now if only....................oh well its still a neat light.

I agree, I think the 10 minute stepdown is appropriate.
 

Bigmac_79

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Nice review Bigmac_79! In your video you mention the LD50 has a sort of soft lockout, in that it requires the button to be pressed about a half second in order for it to turn on (longer than that puts it in strobe from off).

How much pressure is required to press the button? If one wanted to throw this in a pack, either in it's case or without, is there a possibility of accidental activation? From your video, it does not look like a hard lockout is possible when you were replacing the second 18650 while the light was on.

It doesn't take too much pressure to activate, but the button only protrudes a tiny bit beyond the body, and doesn't protrude beyond the head, so it doesn't get pushed by pressure from a flat surface (like laying down on a table). I haven't tried leaving it alone in my bag yet, but an irregular object could certainly push it if lined up correctly. Within the holster, it is significantly harder to press the button, but not impossible. You are correct that it doesn't have a hard lockout--the threads are not anodized, so there is an electrical connection as soon as the caps touch, before you can even screw them in. The manual makes no mention of an electronic lockout, and I can't find one. So, if you need to be absolutely sure, you're going to have to remove the batteries.
 

Capolini

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Thank You! I enjoyed your review.

I got the LD50vn a few hours ago. I look forward to using it tonight. :)

Accidental activation is also one of my concerns. Not so much when I am walking with it in the holster. I have had several lights activate when on my hip and driving!! Caused by my seat belt! When I take Capo for our nightly hikes I am geared up and have to drive 10 minutes or so to the trails! I have learned to "lockout" lights that are capable[this is not] or simply face the holster where there is the least amount of pressure from the seat belt!! I know,,,I could just put the holster on when I get to my destination!!
 

Bigmac_79

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Thank You! I enjoyed your review.

I got the LD50vn a few hours ago. I look forward to using it tonight. :)

Accidental activation is also one of my concerns. Not so much when I am walking with it in the holster. I have had several lights activate when on my hip and driving!! Caused by my seat belt! When I take Capo for our nightly hikes I am geared up and have to drive 10 minutes or so to the trails! I have learned to "lockout" lights that are capable[this is not] or simply face the holster where there is the least amount of pressure from the seat belt!! I know,,,I could just put the holster on when I get to my destination!!

Glad you like the review, be sure to let us know what you think of the light!

Yes, the lack of lockout looks to be one of the few downsides of the LD50, I think I'll just have to keep the batteries out when I'm not using it.
 

Capolini

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Glad you like the review, be sure to let us know what you think of the light!


Yes, the lack of lockout looks to be one of the few downsides of the LD50, I think I'll just have to keep the batteries out when I'm not using it.


You probably know more about this than I do. What would be the reason ALL manufacturers sometimes choose NOT to have anodized threads or a way to "Lock out" the light? It can not cost much extra? My PD12 threads are anodized. The manufacturers seem to be inconsistent with this feature! :shrug:
 

Bigmac_79

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You probably know more about this than I do. What would be the reason ALL manufacturers sometimes choose NOT to have anodized threads or a way to "Lock out" the light? It can not cost much extra? My PD12 threads are anodized. The manufacturers seem to be inconsistent with this feature! :shrug:

I really don't know why they do what they do. :shrug: I have no idea about the cost of anodizing the threads, but my preference is when they are mostly anodized but with a couple mm left bare on the end so the tail can be a little bit loose before loosing connection.
 

Capolini

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I did enjoy using the light tonight for the first time.I like having 5 modes. It will fit well in my rotation which is two different torches a night w/ the TK75vn used twice a week!!!

Again, mine is a bit different because it is modded[LD50vn]. I chose PDTn. That is PREMIUM DEDOME TINT-Neutral. It is my first neutral light and I love the tint!

Vinh added a slab of copper to help distribute the heat/conductivity to the head of the light. a couple pics. below.


bf36eb424d_zpsf7314f7b.jpg



003_zpsf22625dc.jpg



002_zps83697231.jpg
 

Alex1234

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can wait to get my LD50vn !!! looks so awesome. about 2000 otf lumens and over 50 kcd thanks to the dedomed leds :)

I did enjoy using the light tonight for the first time.I like having 5 modes. It will fit well in my rotation which is two different torches a night w/ the TK75vn used twice a week!!!

Again, mine is a bit different because it is modded[LD50vn]. I chose PDTn. That is PREMIUM DEDOME TINT-Neutral. It is my first neutral light and I love the tint!

Vinh added a slab of copper to help distribute the heat/conductivity to the head of the light. a couple pics. below.


bf36eb424d_zpsf7314f7b.jpg



003_zpsf22625dc.jpg



002_zps83697231.jpg
 

ven

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Cracking review bigmac:thumbsup:,love the light,and congrats roberto,that does look very special indeed..........awesome:)
 

selfbuilt

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Interesting light, thanks for the good review Bigmac.

Reminds me a lot of the Skilhunt DT-20 (review here) from two years ago - although that light had a secondary switch that allowed you to alter the number of emitters. Similar kind of common circuitry though, as each emitter could run off a single cell on either well. And it too had non-anodized threads for the screw caps. :shrug: Odd to see an old design (that apparently never sold very well) come back again.
 

Bigmac_79

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Interesting light, thanks for the good review Bigmac.

Reminds me a lot of the Skilhunt DT-20 (review here) from two years ago - although that light had a secondary switch that allowed you to alter the number of emitters. Similar kind of common circuitry though, as each emitter could run off a single cell on either well. And it too had non-anodized threads for the screw caps. :shrug: Odd to see an old design (that apparently never sold very well) come back again.

Thanks for your input selfbuilt! I do remember seeing the DT-20 come out now that you mention it, but I had forgotten about it until now. That's really interesting that neither of these have anodized threads. I don't know much about the manufacturing and anodizing process, but I wonder if it's somehow harder to anodize the threads with the double tailcap design :duh2:. Anyway, I don't know how the sales are on the LD50 but it's been one of the lights I've gotten the most response for on my review, so it seems a lot of people are interested in it. I think the main advantage in my mind the LD50 has over the DT-20 is that it's design is so much slimmer, making it easier to pocket.
 

selfbuilt

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I don't know much about the manufacturing and anodizing process, but I wonder if it's somehow harder to anodize the threads with the double tailcap design :duh2:.
If I were to guess, I would think the issue is the dual tailcap design (with a circuit that can read from either well). If you anodized the threads, you wouldn't know if one tailcap was locked out or not - and so could be accidentally running the light on a single cell. That is certainly not optimal - and likely to be common occurrence if the user has to fully tighten two tailcaps (i.e., you may not be able to tell if both are making contact). It is probably a conscious design choice, to prevent this problem from occurring. But that's just speculation on my part. :shrug:
 

Bigmac_79

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If I were to guess, I would think the issue is the dual tailcap design (with a circuit that can read from either well). If you anodized the threads, you wouldn't know if one tailcap was locked out or not - and so could be accidentally running the light on a single cell. That is certainly not optimal - and likely to be common occurrence if the user has to fully tighten two tailcaps (i.e., you may not be able to tell if both are making contact). It is probably a conscious design choice, to prevent this problem from occurring. But that's just speculation on my part. :shrug:

That does make sense, I can see how a person might not notice if they're only running off a single emitter with one tailcap a bit loose. However, it seems the ideal solution to that would be to just leave about a mm un-anodized at the end, so that it doesn't have to be fully tightened and it's easy to get it tight enough for a connection, but still plenty of room for lockout when you want it.
 
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