Ferei W151B, First Impressions

Ninox_

Newly Enlightened
Joined
Jul 30, 2014
Messages
7
Location
Australia
I've had the Ferei W151B dive light for a few months now but only just had a chance to try it in shallow water. In lieu of a proper review I thought I would post my initial impressions.
The light body is nicely made with a solid and practical feel. The anodising seems good.
The tail-cap has solid trapezoidal threads and what seem to be a pair of well seated quality O-rings. The anodised surface that makes contact with the O-rings is very smooth and I think it will be a reliable seal. This is the only user openable part of the light. Other body joins are possibly glued or just very tight as they don't seem to budge.
Loosening the tail cap half a turn isolates the battery. It should still be completely waterproof in this state but it is pretty tight and would not be a practical way to control the light underwater.
The rotating magnetic mode switch operates easily enough, but I can feel why they recommend lubricating the switch every few dives as it is mainly anodised aluminium surfaces taking the load of a sprung ball bearing switch locator. A high-slip plastic insert might have been a nicer option.
All light control is achieved through the rotating switch. There are three power levels and a flashing mode. The light manual (yes, it comes with a three language glossy booklet) suggests that the light is activated to high mode by turning the switch a 1/4 turn and the other modes can be selected with further 1/4 turns. Sometimes this is how it works but I have found that the mode switching is a bit temperamental and it can flick through all the modes in a single 1/4 turn depending on how quickly or steadily it is turned. This is OK on land but I think it might do my head in when I'm into my third martini. The switch has enough resistance to turning that it should be difficult to bump. When I purchased the light I was hoping that it would have a magnetic switch that activated each mode at a set spot on the dial, so I'm a bit disappointed with the switch.
The glass face appears to have a ruby or similar coating. The reflector is deep and gently orange-peeled.
To the output: Ferei claims 650 lumens OTF for this light and I can't dispute this. It certainly seems that bright. The XML is supposed to be putting out a "neutral white". They don't say which bin they are using but the light is certainly very broad spectrum. There is no green tint here. The red and blue tones in the light are very obvious. It works quite well for telephoto photography in air. I'm yet to shoot with it in the water but it might be quite suitable for macro video (on high).
The beam profile is a narrow spot with a relatively narrow spill. There is an intermediate area around the spot, presumably the effect of the orange-peel reflector so there is not a sharp contrast between the spot and spill. In clear water the beam profile should be quite practical but the spill will undoubtedly be an issue for backscatter in less ideal environments. I'm going to make a spill mask (hood) for one side of the light to give a window through any backscatter.
I have not tested runtimes or regulation yet but I'll try and do that before Christmas and post results here. My impression is that it gets about the claimed runtime and is reasonably well regulated.
The feature of this light that will be a killer for some people is that it appears to use Pulse Width Modulation for controlling light output in its lower modes. I can hardly perceive the flicker on the mid-mode (I might just be imagining it) but it is quite severe on the low mode as soon as you are observing movement. Obviously this could be bad for using it as a video light, not that there are that many occasions when you need less light for video.
When used on high the Ferei gets noticeably hot, even when in the water. The heat seems to be spread evenly throughout the body of the light when underwater. When on land the heat seems to be coming from both ends. I suspect that there are some current bottlenecks associated with some stainless steel components in the tail of the torch. Whatever method they are using to get constant voltage and current to the LED, it certainly has some inefficiencies.

I paid under US$70 for this light while it was on sale at half price. That included a reasonable protected battery (similar to a $5 Trustfire "3000"mah "flame holograms") and a single cell 18650 charger (which I have not been brave enough to use) all branded as Ferei. I don't think I would have paid full price, particularly not given another torch I bought for under $100 (Fenix SD10). I have recently seen the Ferei W151b for AU$80 so maybe Ferei have got the message that it was overpriced.
 

Ninox_

Newly Enlightened
Joined
Jul 30, 2014
Messages
7
Location
Australia
I have now been scuba diving with the Ferei W151b and the Fenix SD10. Both lights worked fine at 24m with the twist switches working well and no leaks.
Backscatter from the spill light was quite acceptable for both these lights. However, I was in relatively clear water. I can show some real world beam shots if anyone is interested. The colour balance for both these lights feels distinctly warm when underwater. The beams have a nice profile.

There have been no issues with the rotary switch on the Ferei. I have not oiled it, but it still feels like new after 5 hours in seawater.

Neither of these lights have a low output mode so if you have to use a light for writing or other closeup and high contrast work, you will have to look elsewhere.
 
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