The C8F UI has (had?) a severe bug (will stuck in moon mode). With that one corrected, it’s a nice UI (SP33V3 seems ok). The only thing I would add is the ability to ramp up- and downward randomly, like Crescendo does and unlike Andúril which annoyingly forces you to wait until you can ramp up after already ramping up. Annoying.
Any kind of regulation in this light? Is there a runtime diagram already?
I’m gonna hafta play with my C8F, as I don’t recall anything evil in the UI.
Only thing I had issue with was turning it really off I’d turn it off via the sideswitch, then unclick the tailswitch, then TCLO the beastie. (Yeah, overkill.) Gotta remember to do all 3 in reverse to just turn it on again. 
Lux-Perpetua,
Thank you so much for posting this, I appreciate. That.s exactely what I needed to see. :+1:
Since I'm a total noob... Would you mind breaking this down a little further for me, please? I've inherited -- long story -- a Torchy and an OlightS1R, and would like something similar. I don't mind going a little larger to get a longer run time. Thanks for any help!
very helpful photo
the advantage of 16340 is that it is lower weight and smaller size
16340, 18350, 18650:
here is the 18350 version:
(pic is a link)
the advantage of 18350 is that it has more capacity
the disadvantage is the battery, and the light it fits into, is larger, and heavier…
your S1R uses a 550mAh Battery, size 16340 (16mm diameter, 34.0mm long),
that weighs about 18 grams
an 18350 Battery (18mm diameter, 35.0mm long),
that weighs about 25 grams,
is available in 1200mAh capacity,
double the capacity of the Olight battery.
however, if we use less lumens, we get more runtime
it can be misleading to focus on maximum lumen runtimes, if in reality we seldom use maximum…
so, be happy with your 16340 light and dont worry about capacity and runtime, instead, avoid using maximum… 
.
16340 is 2mm smaller in diameter than 18350
Example Sofirn SC21
a light whose head was designed for a 16340 body tube, will not accept an 18350 body tube, because the diameter is 2mm larger… the parts wont screw together.
Example Sofirn SC31
an 18650 flashlight can easily use an 18350 body tube, because they are the same diameter.
16340 in 18350 body tube:
18350 in 18350 body tube:
.
Thanks! I went to the Sofirm site and found the IF25A, so am looking into it now, too!
Don't laugh, but there is a point to what I am seeking. I am blessed to have a large backyard. Large enough that I have to sometimes search for my dogs at night, after letting them out. I'm looking for 1k lumens or so, such that I can light up 1/2 to 3/4 of my yard enough to see where they are/what they are doing. But because I am sometimes wrangling them, a small light I can clip to my collar is most desireable (once I find them, LOL).
Thank you for the explanation!
one man’s small is another man’s large…
I suggest you develop some data regarding the weight of each light you consider, as a basis for comparison.
.
OlightS1R compare and contrast to Sofirn SC21
Olight LED is not HIGH CRI
to me, High CRI is a required feature, and is the reason I no longer own any Olights.
Sofirn offers High CRI, Olight does not
Olight UI is not Anduril
I like the Olight UI, but not their LEDs
Anduril UI is MUCH more complicated, and requires a LOT more clicking to access all the extra features…
Anduril is a very high output capable UI. People have been hurt when the light accidentally turns on in their pocket. Prudence dictates locking out lights that run Anduril. Locking out requires 4 clicks to lock, and 4 clicks to unlock.
to me that is a ridiculous amount of clicking, and one of the main reasons I do not own any Anduril lights myself
otoh, if Anduril UI interests you, the SC21 is the smallest and lightest Anduril light presently available
to be fair, Anduril is extremely versatile and capable, and can be set up to be as simple or as complex as you like…
warning, if you slide down the Anduril Slope, you will soon be buying an Emissar D4V2 with aux lights… and more… you have been warned
welcome to our support group… LOL
Based on your response, I went over to the general area and spelled out "small". Thank you for your help!
Will
I think the SC21 is not anduril.
I dont own the light, and you might be right…
the word Anduril does not appear… so, who knows?
it does say:
Group 1: Stepped mode group
Group 2: Ramping group
SC21 does not use Andúril but more or less a quite similar UI as SP35. An excerpt from the manual...
thank you
similar 4 click lock and unlock as Anduril
similar stepped and ramping modes as Anduril
I dont know all the differences between Narsil, Bistro, Anduril etc
imo ramping is a useful UI
as is the option to use stepped modes instead
so afaict, this is the smallerst light available today, with a ramping UI…
Is there an AA/Eneloop version of a light with a ramping UI?
(that does not require LiIon?)
After a long wait mine is on its way.
Here’s a pretty decent video review. Hate to say it, but it might push me over the edge…
I have one and it’s awesome for features, lumens and size. I would only step down to an AA or AAA if I wanted to go smaller than the SP31 Pro 18350. And now I’m locked into the 31 Pro, Anduril as well.
That video does make it look tempting.
One question I have, is that can it go directly from moonlight to ramping by continuing by holding the button in moolight, like the SC31 Pro can?
I like the UI on the SC31 Pro.
glad you found an 18350 Anduril light you enjoy
can you please tell us how much it weighs?
My favorite 18350 light weighs twice as much as an SC21
both is best 
and
size matters… lol
aaa, 16340, 18350
Right at 80.0g inc. battery and clip, or 2.82 oz.
Are those slots on either side of the switch for trit capsules?