BLF Q8: Mini-review with X-Ray Image and Diffuser

This is a mini-review of the BLF Q8 made by Thorfire, and designed by many creative minds from Budget Light Forum. As there is already plenty of information out there about this light, I won’t go into great detail. The Q8 is a modern take on the Sky Ray King (SRK) style light (Soda Can size), where quality has otherwise taken a nose dive in recent years with manufacturers using cheaper and cheaper components (including fake LEDs). However, slightly larger than SRK lights have made a recent resurgence thanks to the “lumens wars” from many manufacturers, at varying price points. The Q8 uses 4 Cree XP-L (V6 3D) emitters, and uses up to 4 button top 18650 batteries in parallel.

This review is of a Q8 built in the second production batch. Unusually, I actually bought this light myself!
Product page: https://goo.gl/S5wde9
For those who’ve been living under a rock and missed out on the $40 group buy, you can get it for $48.50 using code: e5a236

Note: Outdoor beam shots added later in this thread! (Rather than updating original post).

Packing and Design

The BLF Q8 arrived in a padded cardboard box, surrounded by more padding. The box was intact after shipping. Included are the Q8 flashlight, spare O-ring, and two sets of instructions (larger instructions and smaller Narsil cheat sheet).

There are some discrepancies between these two manuals in regards to output % levels e.g. mode group 4 is 2-10-40-full in the Narsil cheat sheet or 0.25-3-33-full in the instructions. The latter seems to be more accurate to measured output. The product page on Banggood’s website shows measured output levels in lumens, though due to use of a FET driver these are only approximate (and seem to be somewhat lower than my measurements with VTC6s @30s), though very useful a rough guide.
Update: A newer version of the cheat sheet is under http://bit.ly/narsil-cs

I could not see any major flaws in my light. The four Cree XP-L LEDs are well centred. There were no dings or damage on the anodisation. The electronic side switch works well, and is evenly illuminated (the light is green). The threads could do with some more lubrication. Due to the battery carrier configuration, the head needs to be screwed/unscrewed with light facing upwards (lens to sky). Shaking the light hard did not affect functionality.



The tripod mount is an excellent feature and fits my tripod mount perfectly. This feature should be in all lights in this category (3x or 4x18650) - take note: Haikelite!

The X-ray image below is taken with the switch side on, and Sony VTC6 with button tops (from Aussie eBay seller supersports600) in the battery tube. Note that x-rays are a diverging beam, which creates some distortion (notable at the lens and tail).

User Interface

The BLF Q8 uses the Narsil user interface. By default the light uses ramping to increase/decrease brightness, which should be good for most users. For people like me (photographers) who prefer to use specific output levels (well, as specific as you can get on a direct drive light), you can select one of 12 different mode groups. It should be noted that as this light uses a FET driver, that when using the higher output modes that the brightnesses (and thus heat output) are not linear throughout the runtime and should follow a typical direct drive discharge curve.

The light can run continuously on a tripod from fully charged batteries without getting too hot on 40%/33%/1500lm mode (Narsil cheat sheet/manual/product page respectively) at 21C indoors. This is comparable to the much larger Convoy L6 on 33%/high mode. Having this level of continuous output (taking onto account the direct drive discharge curve) in a compact package is very useful for my requirements. In cooler and windier conditions and/or hand heat-sinking I would expect that continuous running from fully charged batteries with higher output would be possible.

As the batteries become more discharged, then the Q8 can be run continuously in higher output modes. This is a good reason to use the heat controlled step-down, instead of timer based step-down.

Narsil is highly configurable user interface, which allows for configuration of ramping vs modes, moonlight on/off, strobe options (I like the inclusion of both single frequency and varying frequency strobes), step-down, etc. Changing configuration is fairly easy, hold the switch to enter config mode, follow the flashes as it moves through each configuration setting, and tap the switch the required number of times for any configuration settings you want to change. There is no tactical/momentary functionality, but the Q8 is not really a light for tactical use cases. Whilst the 12 mode groups cover most user requirements, there are limited options in the 250-1000 lumen range.

Beam and Output

The BLF Q8 uses 4 Cree XP-L (V6 3D) emitters in a 4 smooth reflector configuration. The lens appears to be AR coated in my sample. The emitter and reflector configuration creates a floody beam, with hotspot. There is noticeable tint shift between the yellow hotspot and almost pure white spill beam. The tint is neutral white and appears to be around 5000k (very similar to my Convoy L6 5000k). Due to the quad reflectors, the beam doesn’t have a defined circular edge, but instead has a quad clover leaf appearance which reduces with distance. This is not an issue unless you are a white wall hunter.



The Fenix AOD-L diffuser fits well, and also diffuses the light well. Due to the shape of this diffuser there is more forward than rear projection, and the forward projected light is warmer than side or rear projected light.


My setup for measuring output (integrating spare bedroom) is not too accurate for high output lights (>2000 lumens), and was giving me readings of 6000 lumens at 30 secs with freshly charged Sony VTC6. This seems to be higher than other user’s measurements. Taking degrees of error into account I can safely say that the output is in excess of 5250 lumens at 30 secs. Due to use of a FET driver, your mileage will vary in higher output modes depending on the types of battery used and voltage.

Conclusion

Things I liked:
Good build quality
Flexible user interface
Very good output to size ratio
Neutral white beam
Good heat handling
Tripod mount

Things I didn’t like (I’m being very picky here):
No momentary (though this light is not aimed at the “tactical market”)
Limited output modes in 250 to 1000 lumen range
Discrepancies in output levels between manuals
Output levels are not constant throughout runtime

The team behind the Q8 and Narsil on BLF, and Thorfire, should be very proud of the outcome of the Q8. Whilst other decent contenders in the “slightly larger than SRK style” market have made a resurgence during the Q8’s development, this light still holds it own. This is an excellent high output light, with good built quality, and heat handling for its compact size. At the US$40 group buy price this light is excellent value for money. If Thorfire continue to make this light in the future, it would still be good value for money even if commanding a 50% to 100% higher price tag.

Thanks for the review!
Cool xray pic!

Thanks for your input into such an amazing light!

Nice review!

And that :sunglasses: X-ray shows something surprising to me about the 2nd run lights, at least I have not heard it mentioning yet, and my 2nd batch lights are not in so I can not check:

It looks like they completely re-did the way that the ledboard is fixed in place: the heads of the two screws are in the driver cavity now, and they screw into the reflector. So the ledboard is now sandwiched between shelf and reflector which 1) clamps the board down on the shelf more evenly with the force applied via the led centering rings, 2) now completely prevents twisting the reflector over the ledboard, 3) allows removing led-board+reflector combo by unscrewing those 2 screws from the driver side. I have to think about if there are downsides of this approach, perhaps the clamping force can not be as high as when the ledboard is directly screwed on the shelf like in the first batch.

Nice review with a twist stephenk. :+1:
27 and no rain here today. :slight_smile:

Nice review.

I was staring at those screws for a while trying to figure out what I was look'n at, then saw your post, djozz - wow, think it's overall better, but threads in the copper MCPCB is a little strange to do - can't recall seeing that before.

Its interesting to also see the overlap in the threads and the amount the springs compress.

24 here today (which is –8 on the QLD temperature scale) and rain forecast for the next week. :frowning: Really want to get some outdoor beamshots and do some light painting with the Q8.

I think the threads are in the reflector, with the MCPCB squeezed in between shelf and reflector.

Ohh, could very well be. It's different for sure, but we actually wanted at least two reflector screws way back in the beginning, so if that's what they did, now we have 3 .

Hhmm, got a guy at work that rcv'd three of the new ones, but he's giving two away - think he still has two. I looked at one but not sure now - could have sworn I took the driver screws out, can't recall seeing those screws. Mine are still half way across the country somewhere, but should get one by Thursday.

If it is what it looks like, it surely proves that the Q8-team has no control whatsoever on what Thorfire is doing :party:

Well, as long as their changes do not mess up the Q8 I guess I can live with that :frowning:

Well the X-ray is most interesting.

IF what were the MCB fixing screws have now been re-purposed, turned around, and are now screwed into new threaded holes in the reflector, then I think I probably like it better than before. Though the screws could be a lot longer, with better thread engagement, the X-ray shows plenty more depth in the new holes in the reflector.

And, IF the assumptions are correct (insufficient resolution to see any threads) the central fixing screw is pretty much redundant

However this needs verifying with a teardown

Personally I have always considered that the central fixing screw is misconceived. Instead of just clamping the MCPCB against the reflector (and dishing it in the middle when over-tightened) it could have been arranged so that the head of the screw butted on the rear side of the shelf (with LED wires led through their own hole, or a “bridging piece” used to achieve the same effect).

The most important area for the MCPCB to be clamped against the shelf is directly beneath the LEDs. A properly configured central fixing screw butted against the rear of the shelf would achieve just this, force being applied from the screw to the reflector, through the emitter spacer rings, directly to where it is needed.

To be frank, no other screws required, except to locate the MCPCB in a symmetrical manner, for cosmetic reasons.

Do Thorfire have anything recognisable as a change control process, or do they just make things up as they go along ?

Edit: for The Miller, please understand this is not a criticism of the BLF design, just my personal observation of how things could be done slightly differently, i.e. “more than one way to skin a cat”.

And it seems as if Thorfire have just come up with yet another one. Nothing could be worse than the one Tom E got, with far to short MCPCB securing screws, and insufficiently (or not at-all) threaded holes in the shelf.

Did I miss something about the reflector being distorted on the Q8 from the central screw?

Think he means distorting the MCPCB, which does happen. On a couple of the 1st 500 Q8's, the reflectro screw was super tight and the MCPCB was bulging up in the middle - easy to tell when sanding the backside. I took a big punch, gave it a couple good hits from the top in the middle and it actually did flatten it out - proven by flat surface sanding.

Yes Tom, that’s what I meant. A great big over-tightened central screw that does nothing at all useful. The only thing holding the MCPCB tight against the shelf were the other two small MCPCB fixing screws, which in at least one of yours, weren’t even doing that. The only thing pressing anything together would have been the bezel/lens/O-ring.

Edit: take a careful look at the X-ray, It may be that you can see the MCPCB being dished by the central screw, though to be fair it looks so gross and obvious that I must surely be mis-interpreting it.

Edit: and take a look at the lovely fit of the threading from the tube to the head. And contrast that with the crappiness of the tail cap threads.

Beautiful radiography by the way, forgot to say that, really nice and useful. Hospital or industrial ?

Medical x-ray unit, imaged during system “testing”. Required about x6 more exposure than an 18650 tube light (55kVp/30mAs).

As it’s still raining here in Brisbane, preventing outdoor beamshots, I thought I’d get an indoor beamshot instead!

Nice pic!

^ Thanks. A few more photos coming soon…

I have to admit that when I was comparing the Q8 against the L6 indoors (for white wall beamshots) I was a bit underwealmed. Yes, it is brighter, but not by a huge degree. However after using the Q8 outdoors I was amazed with the Q8’s ability to turn night into day, and such a nice neutral tint too! It’s great to have so many lumens in a light that doesn’t take up half my camera bag!!