I received the Fenix FD40 from Banggood for the review. Here’s the purchase link and a coupon: SH6%OFF
Usual Fenix box for the FD40
Inside the box: the light, lanyard, spare o-rings, sheath and manual.
Some pics of the FD40
Some milling on the body helps gripping the light
Tailcap big wide and flat
The distinctive feature of the FD40 is this strange optic with zoom capabilities.
Fully twisted
Fully untwisted
There’s a tripod screw on one side of the light.
The light works both with 26650 and 18650. There is an included adapter to use 18650 batteries without rattling or contact issued. Here you can see a 18650 battery with the spacer and a 26650 battery without. There is plenty of room for the 26650.
The positive pole of the FD40 is a spring, so the light can work with button top and flat top batteries.
Metallic switch at the head.
Anodized threads at the tailcap allow physical lockout of the light.
UI
A long (0.5”) press of the switch turns the light on at the last used mode
When the light is on click once to cycle between the modes (ultralow, low, medium, high and turbo)
A long (0.5”) press turns the light off.
The light has memory mode for constant output modes.
From off, a long (1.2”) press, turns the light on at strobe.
Beamshots
Before the beamshots, I believe I have to spend 2 words about the optic.
The reflector or TIR optics that many lights use represents a fixed format. You have a pre-determined wide and spot angle, each with its own brightness. The “zoom” system allows to swtich from a completely flood circular beam to a spot focused beam, with all the possible intermediates configuration in between.
Yes, there are some reflectors or optic system that give you a very wide and usable spill with a decent throw, but when you need to use them at close distances, a flood beam will be better for your vision.
However, the zoom system has its limitations:
a) At the “wide” position, the zooming system is very efficient in transmitting the light, but the more you get to the “focused” position, less light will exit the optic, resulting in less output. The extent of this effect greatly depends on the quality and type of optic. From my measurements, I found a 20% loss in output when moving from the “wide” to completely “focused” position.
b) The more you move from the “wide” position, artifacts will appear.
With these things in mind, I believe that a zoom system is more versatile but does not excel in any particular scenario. Even at the “wide” setting, the beam is not as wide as the one generated by other optics, like TIR used in headlamps, or without any optic, as in the pure flood lamps.
But for covering the different kind of beams generated by a zoom light, you will need 2 or more lights.
Beamshot in the real world
Wide
Focused
Here you can see the difference from what I described above. All the strange protrusions on the optic make the beam less focusable and wider. So, even when you are in the zoom position, with the max throw, there is still a very wide spill with enough light to see where you are going with your feet. However, this will translate in less throw and output.
You can see it more clearly in this video.
Output and runtime
Output has been tested both with unprotected LG MJ1 18650 and Keeppower IMR 5200mAh 26650.
At the end of runtime test the cell were above the minimum discharge voltage recommended.
My thoughts
Fit and finishes are good as you would expect from Fenix.
Regulation is good on the tested levels. I like having a sheath, but I’d like to see it have MOLLE capability.
Compared to other focusing systems, the one on the FD40 has less throw but offers a beam with a very usable spill even in the focused position.
I like to have a tripod mount in the middle of the light. In the wide position it can work really well as a flood light.
The I miss the shortcuts to low and turbo mode, that I usually like on all UIs.
I would like to see a NW version of this light.
Thanks to AntoLed for thecamera and the luxmeter
Thanks to P.P. for the beamshot location.
