And finally when you do understand basic optics, in practice it appears just a bit different :party:
(no, actually it surprises me how good it does apply in practice)
Thanks to both of you. I have tried sanding down an aspheric lens before and it was difficult to do without a sander, and yeah those glass dust are really nasty. I don’t think I want to grind down any lens anymore, will keep on looking.
By the way I really dislike that these sellers never advertise the focal length of some of their lens, which is a crucial information IMO. What I can do is to compare the thickness of the aspheric lens itself to my 1405 stock lens and make a rough estimation from there.
Throwing out a question to everyone and want to make sure if my understanding is correct: Thicker lens means shorter focal length in general, right?
Sorry for the newby questions…
Is the second lens from Fasttech what you guys call a fresnel lens? I see it has the stepped / ripple effect.
And, what is the difference between a precollimator and a precollimator lens?
No, just textured. This will help you understand the fresnel lens better.
And the difference between “precollimator” and “precollimator lens” is just the word lens after precollimator.
Thanks for the good reference KKW… I’m not sure what a precollimator lens looks like, can you maybe post an image please? Is a TIR lens a precollimator lens?
A precollimating lens is just another smaller aspheric lens mounted close to the LED. It catches some light that would normally be lost because it wouldn’t hit the front lens because it’s coming out at too steep an angle, and angles it forward towards the front lens.
Just for the record, today I swapped the stock lens in my 1405 with a 66mm lens from DX (nothing else was changed at all) and I got 431kcd at startup.
So it is basically:
403kcd at startup with 1405 stock lens.
431kcd at startup with DX 66mm lens.
But the DX lens quality is actually very inconsistent too. I bought a few pieces of the DX lens before and some of them are really, really bad to say the least. But this one is okay and actually better than the 1405 stock lens so yeah, lens does make a difference.
Lens, emitter, driver & battery makes the difference. But some times bad centering can mess up the performance.
I used to get from 20-40 kcd more just with little fiddling with lenses and emitter.
Cajampa, yes that’s the one, but please be reminded that the quality is inconsistent and it is pretty much a lottery. I got a very bad one which literally projected a few ‘squares’ instead of just one when fully focused.
Luminarium iaculator, I think the centering is fine with mine, as the LED retaining ring really does its job. Btw do you think the Xsearcher lens is really good and can I order them separately?
Got it, thanks KKW
Xsearcher lens will not work with 1504 neither will Nightmaster V2 lens work with 1503.
They could work with very big spacer but that would look like c.r.a.p.
Dereelight lenses can also have up to 30% kcd/clarity difference in same batch, and while they are better lenses than UF they do not have good zoom out function. Hate to say but UF is more versatile flashlight with just bit less throw (up to 30% less than Deree).
Anyone found replacement springs (big, oddly shaped) to match the stock UF-1504?
(borrowed image from earlier in this thread)
I bought a few extra pills, and find most of the drivers I have that came with springs don’t make contact with the battery + terminal, they’re too short.
So are all the loose springs I have.
I have just used the carobronze springs that fasttech, but those aren’t very large so i am puzzled why you would have issues with the cells making contact.
IOS sells a bunch of different springs, maybe one of those could fit right.
The substitute drivers I’d tried so far — qlites — came with short and small-diameter springs, and I have some fairly short flat top 26650s, so the combination didn’t connect. And tiny central pads to solder too as well, I guess I’ll have to try ‘upside down’ springs. I’ll try the biggest I have and see, maybe that’s all I need.
Just wondered, I’d never seen springs like the ones that came stock with the light.
Either you do the upside down trick with some longer springs, or you can just add a few rare earth magnets on your battery positive. You can also add a small solder blob on your battery positive for that matter.
Yeh, I’m a belt-and-suspenders-and-airbag kind of guy so I won’t solder onto li-ions, nor trust magnets not to slip and short positive to battery tube. When the cell is loose enough it can always bounce and let a magnet slip, eventually.
But as long as I don’t use the shortest-spring drivers and the shortest cells together, it works OK.
I’ll try the upside-down-spring thing from here on out, on drivers going into this light.
(I bought several extra pills, to be able to experiment with various drivers and emitters easily)
Where did you get the extra pills from?
Then put it on the negative side (the magnet) so if it slips the worst that happens is your light turns on. That said, I’ve never had one slip off the negative end, the wrap around the edge seems to keep them from shifting very far off center.
+1 !
the positive side is worst place for a loose piece of metal…