Sofirn DF10, 18650 diving light with magnetic mode ring, my thoughts

djozz · 2019-12-08T20:47:18.000Z

The DF10 is a new Sofirn light and I just got it in the mail yesterday. It is a compact, 30mm reflector diving flashlight with a 5000K 90CRI Samsung LH351D led, and it is operated with a magnetic ring that clicks in at 6 positions.

I think it looks good, feels well-built with lots of o-rings and fairly stiff lube in the threads, and is compact even for a non-diving flashlight. The beam from the LH351D in the smooth reflector is nice and clean and it indeed measures 5000K and 91CRI, with a bit positive duv, as expected from this well-known led (I failed to write down the exact numbers). In reality the tint looks neutral white with no rosiness but a slight (non-disturbing) hint of green. This is also known from this led.

The magnetic ring is of course the key feature of this light. It has six positions going round: off-high-med-low-strobe-SOS. High is about 900 lumen, the lowest mode is too close to high, should be lower. From off, the other direction gets you SOS directly. The ring rotates very smoothly, a bit too easy even, unwanted rotations may occur in your pocket or bag, so locking the light out by slightly unscrewing the tailcap is needed. The parasitic drain in the off-position is just 77 microamps, draining your 3000mAh battery in 4 years.

The mode order by the ring is hopeless for me:
*from off the two options are high and SOS, while I always want to be able to start in low.
*as said, the low is not low enough, its function is not much different from medium
*two (for me useless) blinkies are directly in the rotating sequence and are unwantingly activated way too easily (strobe is next to low :confounded: ).

Conclusion:
This would be a great light if the blinkies were left out (do divers need strobe and SOS?): just 5 well-spaced modes starting from a real moon to max , combined with the 90 CRI neutral led would have made this one of my favourite lights. From off, one direction then gets you low to high, the other direction gives you high to low. But how it is now, after the news will wear off, it will end up in a drawer.

Small mod: I sliced the led to increase throw and lower CCT and duv. It was slightly unsuccesful because while CCT went down to 4300K, the duv was still a bit positive (+0.0024, at low it is even +0.0043) after the slicing. I still have to optimise focus, probably sand off a bit from the underside of the centerpiece.
It gave me the opportunity to look at the driver. It has 3 magnetic sensors, so it must detect the ring magnet half way two sensors as well.

maukka · 2019-12-08T20:50:31.000Z

Oh, interesting, nice magnetic UI, nice emitter - keeps reading - oh, the UI.

Thanks for the quick overview.

BTW, didn’t you know that strobe scares off sharks? Well researched fact

djozz · 2019-12-17T22:15:10.000Z

Update: I sanded a bit off the underside of the centerpiece and now the beam is quite perfect.

nquinn · 2019-12-21T03:46:50.000Z

How are you reviewing a diving light as a non-diver?

You might realize that a very low mode you might want out of the water would be 100% useless in the water because it would simply be too dim.

1stein · 2019-12-21T06:39:33.000Z

Great info, thanks a lot. What method did you apply for sanding?

ggf31416 · 2019-12-21T08:30:22.000Z

I don’t think divers care too much about their night vision unless they are special forces. Unless they dive at night, which sounds dangerous, there is no time to adapt to darkness anyway.

djozz · 2019-12-21T11:21:05.000Z

nquinn:

How are you reviewing a diving light as a non-diver?

You might realize that a very low mode you might want out of the water would be 100% useless in the water because it would simply be too dim.

ggf31416:

I don’t think divers care too much about their night vision unless they are special forces. Unless they dive at night, which sounds dangerous, there is no time to adapt to darkness anyway.

I have not reviewed this light as a diver flashlight but as a non-diver flashlight, because for a diving light it is very compact and handy so it has its merits as a normal flashlight too. I wonder if this light is even targeted at divers btw, the waterproofness looks better done than normal flashlights but the glass is not very thick for instance, and not all the o-rings were lubed.

I used to have a Sofirn SD03 diving light (my impression here Sofirn SD03 diving light, first thoughts ), that seems much more a serious diving light to me (everything very thick and sturdy and well-fitted and thickly lubed) and so I judged it like that. I have not posted about it there yet but (after a led swap to a 5000K 90CRI LH351D) I gave it to a collegue who is a diver for testing and after several dives with it he was so happy with the light that he asked to keep it, so I do not have it anymore.

WindyCity · 2021-01-21T17:02:17.000Z

Does it take button top or non button top? unprotected cells?

d_t_a · 2021-01-22T09:58:16.000Z

WindyCity:

Does it take button top or non button top? unprotected cells?

DF10 accepts button-top & flat-top 18650’s. It also accepts unprotected & protected 18650’s, per my testing…

WindyCity · 2021-01-27T17:38:45.000Z

Thank you! I will order some flattop unprotected ones

JaredM · 2021-01-28T21:19:46.000Z

I wonder how easy a firmware to write for this light would be after using gcharts pic12 adapter… What did you mod today? - #9651 by gchart