Holy Hot Spot Batman, 824kcd! (Formerly, 100mm Aspheric Lens at Fasttech)

95 posts / 0 new
Last post

Pages

ImA4Wheelr
Offline
Last seen: 1 month 5 days ago
Joined: 02/03/2013 - 14:51
Posts: 7935
Location: SC
Holy Hot Spot Batman, 824kcd! (Formerly, 100mm Aspheric Lens at Fasttech)

By the way, that's an actual quote from the series.  The below picture is an dedomed XM-L2 U2 1A at about 7 amps.  Mouse over is dedomed MT-G2 (probably around 5 amps).  The beam is aimed at a tree that is about 250 feet away and 70 feet tall.  The light hitting the tree to the right is from the glow of the PVC head.

The lens I asked about originally in this thread was waiting for me when I got home.  Big, low-profile honker.  It was packed with an Allen wrench against it.  Bad form FT.  Just for S's and G's, I decided to hold it up in front of my latest DST build (with the reflector portion of the head off) and aim it at my lux meter from 10 feet.  Got frickin 790kcd!.  Tried the same thing with a dedomed MT-G2 at about 6 amps.  Got 399kcd!  No wavien collar or anything.  Just held in mid air by hand.  The die image is very small.  At ten feet it barely covered the light meter sensor dome.

EDIT: Redneck engineered a quick light to go have some fun with it.  Now measures 824kcd.  I'm sure it can be adjusted higher, but had to get out and try it out in the wild.

The beam is so tight fully focused, that it only seems to make sense to use this lens in a zoomie.  It floods beautiful and wide.  Wider than any other lens I have ever used.  Image of die seems to have a slight shadow, but it could be the white PVC I used to fab a temporary head.  There are some pics of the funny temp light at post 25.  I estimate the focal length to be about 4.75" to 4.875".

Edited by: ImA4Wheelr on 11/19/2015 - 13:02
garrybunk
garrybunk's picture
Offline
Last seen: 2 weeks 4 hours ago
Joined: 10/31/2011 - 09:25
Posts: 6098
Location: Johnstown, PA

Hmm . . . what's your intentions for its use?  You have a light that takes a 100mm lens?

-Garry

My Bike Lights Thread, Optics (TIR) Comparison Beamshots, Diffusion Techniques

, MTBR’s Lights & Night Riding Forum
NOTE: Now hosting my photos from my Google account. Post up if you can’t see them. Older photos hosted on Photobucket or Flickr may disappear (PM me if you want access to them).
ImA4Wheelr
Offline
Last seen: 1 month 5 days ago
Joined: 02/03/2013 - 14:51
Posts: 7935
Location: SC

Redneck thrower at first.  I noticed this weekend that 1 1/2" PVC can be force threaded onto a DST.  So need a 1 1/2" to 2" bushing.  Than a 2" to 4" Adapter.  Dedomed xpg2. Boom!  100mm Aspheric!  That's what I'm talking about!

Of course, my luck the lens will suck.  But if it does, at least I can take one of the PVC parts back for a refund.  I'll still be out $8+ plus the cost of the bushing.

I ordered, but still have a window to cancel.  Anyone used this lens yet?

 

garrybunk
garrybunk's picture
Offline
Last seen: 2 weeks 4 hours ago
Joined: 10/31/2011 - 09:25
Posts: 6098
Location: Johnstown, PA

Ah, should have figured!

1

And I should have put 2 and 2 together (link to post#238)!

-Garry

My Bike Lights Thread, Optics (TIR) Comparison Beamshots, Diffusion Techniques

, MTBR’s Lights & Night Riding Forum
NOTE: Now hosting my photos from my Google account. Post up if you can’t see them. Older photos hosted on Photobucket or Flickr may disappear (PM me if you want access to them).
Stockton-Rob
Stockton-Rob's picture
Offline
Last seen: 10 months 2 days ago
Joined: 10/24/2012 - 02:38
Posts: 213
Location: Stockton-on-Tees, UK

might throw a bit that eh?

and the lord did utter….‘let there be light’……..and CREE said ‘how much?’

keltex78
keltex78's picture
Offline
Last seen: 1 year 4 months ago
Joined: 03/18/2011 - 10:15
Posts: 3705
Location: Texas

Hmmm.... I don't know optics so I may be totally off base with this but:

That low profile lens looks like it may have a long focal length. Long distance from the emitter would mean more light lost off to the side and less light focused out through the lens?

DrJones? Anyone?


Keepin’ the “B” in BLF

Don wrote:
It sounds like the XM LEDs won’t really be suitable for flashlight use. Pity…

ImA4Wheelr
Offline
Last seen: 1 month 5 days ago
Joined: 02/03/2013 - 14:51
Posts: 7935
Location: SC

LOL.  Love it Garry.  I like that better than the most common last heard words from a redneck, "Hey y'all, watch this!".

 

I'm hoping, Stockton-Rob.  I need to start playing with upside down reflectors to see if I can approximate a Waven Collar.  There will be some room to play around with this setup.  Something tells me the lens may be a let down given it's cost though.

ImA4Wheelr
Offline
Last seen: 1 month 5 days ago
Joined: 02/03/2013 - 14:51
Posts: 7935
Location: SC

That makes sense Keltex78.  If I understand what Djoss told me once, longer focal length means tighter hot spot.  Hopefully, the bigger diameter makes up some for the longer focal length.  Let's just hope it's not too long.

djozz
djozz's picture
Offline
Last seen: 5 hours 4 min ago
Joined: 09/07/2012 - 17:04
Posts: 17993
Location: Amsterdam

Yes, throw with an aspheric is trade-off: if the diameter is the same the thicker lens will catch more light and puts it in a bigger hotspot, the thinner lens will not catch a lot of light (the rest is lost), but puts that little bit into a smaller hotspot. So throw will not be too far off in the two cases, but I prefer the efficiency of a thicker lens with large hotspot.

ImA4Wheelr
Offline
Last seen: 1 month 5 days ago
Joined: 02/03/2013 - 14:51
Posts: 7935
Location: SC

Thank you Djozz (Sorry for misspelling your screen name above).  This lens appears to have an convex curve (Not sure this is the right word, but the glass curves away from emitter going towards the center) on the inside face too.  I know it would just be an educated guess without knowing the specifics, but do you have any thoughts on how that may impact the beam?

djozz
djozz's picture
Offline
Last seen: 5 hours 4 min ago
Joined: 09/07/2012 - 17:04
Posts: 17993
Location: Amsterdam

ImA4Wheelr wrote:

Thank you Djozz (Sorry for misspelling your screen name above).  This lens appears to have an convex curve (Not sure this is the right word, but the glass curves away from emitter going towards the center) on the inside face too.  I know it would just be an educated guess without knowing the specifics, but do you have any thoughts on how that may impact the beam?

I do not see that, in the FT pictures the underside looks flat to me. 

One could experiment with two of these directly on top of each other. You will loose some light from the extra reflections off the extra surfaces, but it will more or less act like one thicker lens Smile

Ramblings
Ramblings's picture
Offline
Last seen: 2 months 3 weeks ago
Joined: 01/09/2013 - 04:05
Posts: 761
Location: Australia

I just ordered this a few hours ago. Going to resurrect an old old build. It's actually a perfect fit.

 

I don't think sandwiching two is the best idea, the amount you lose at the interface between the two lenses can be exemplified by cracked glass.

You are the light of the world. Like a city on a hill, you cannot be hidden.
People do not light a lamp and then hide it away, instead they put it where it gives lig

bibihang
bibihang's picture
Offline
Last seen: 1 day 11 hours ago
Joined: 11/10/2011 - 09:32
Posts: 2445
Location: Malaysia

Yeah, this is how I understand it, assuming everything else is the same,
100mm lens with low convex profile – long focal length, project smaller spot (lesser light captured)
100mm lens with higher convex profile – shorter focal length, project larger spot (more light captured)

But they both have the same light intensity in the spot.

You may use dual-lens system to ‘shorten’ the the focal length of the 100mm lens – resulting a larger projected spot with still the same intensity.

(I might not use the correct technical terms here.)

Pok
Pok's picture
Offline
Last seen: 2 years 2 months ago
Joined: 03/26/2011 - 15:23
Posts: 928
Location: Thailand

Maybe focal length is 140mm same as I got 2 from DX.

http://dx.com/p/99mm-replacement-glass-lens-for-flashlights-43043

Fritz t. Cat
Fritz t. Cat's picture
Offline
Last seen: 2 years 10 months ago
Joined: 05/07/2013 - 00:33
Posts: 2535
Location: Si Valley

I ordered one of their smaller lenses but don’t have it yet.

Flashlight designers should look at lighthouses and pottery.
这些谁设计的手电筒应该看灯塔,以及在陶器。

lightme
lightme's picture
Offline
Last seen: 5 years 7 months ago
Joined: 11/12/2012 - 19:51
Posts: 615
Location: WV

Ramblings wrote:
I don’t think sandwiching two is the best idea, the amount you lose at the interface between the two lenses can be exemplified by cracked glass.
It adds a couple extra reflective surfaces but back to back, the focal point should be closer and capture more light. Bridging that thin gap with optically clear silicone could eliminate or at least drastically reduce those reflections.
panthervision23
Offline
Last seen: 7 years 9 months ago
Joined: 02/19/2013 - 00:37
Posts: 545

Very clean. No I haven’t tried it yet. I thank you for showing us this lens. It might come in handy if I need some lens-changing in the future.

comfychair
comfychair's picture
Offline
Last seen: 5 years 5 months ago
Joined: 01/12/2013 - 05:39
Posts: 6198

panthervision23 wrote:
Very clean. No I haven't tried it yet. I thank you for showing us this lens. It might come in handy if I need some lens-changing in the future.

http://en.wikipedia.org/wiki/Mad_Libs

VFMaddict
Offline
Last seen: 1 year 7 months ago
Joined: 06/03/2011 - 08:47
Posts: 1454
Location: London

I have no doubts that that lens would make one hell of a thrower. That’s obvious because its close to frisbee sized.

"You are making progress if each mistake you make is a new one."

Remember - Most great discoveries start with maki

ImA4Wheelr
Offline
Last seen: 1 month 5 days ago
Joined: 02/03/2013 - 14:51
Posts: 7935
Location: SC

LOL VFM.

 

Way to go Ramblings.  Now lets see what we can do with these bad boys (Well, I hope they kick ass).

ImA4Wheelr
Offline
Last seen: 1 month 5 days ago
Joined: 02/03/2013 - 14:51
Posts: 7935
Location: SC

POK wrote:

Maybe focal length is 140mm same as I got 2 from DX.

http://dx.com/p/99mm-replacement-glass-lens-for-flashlights-43043

 

Interesting.  Says 80mm in the link, but I'm not surprised it is wrong.  Are they actually 24mm thick as advertized?  If so, they it would seem the lens in the OP would have an even longer FL since it is only 19mm thick.   How are the lenses working for you?

Pok
Pok's picture
Offline
Last seen: 2 years 2 months ago
Joined: 03/26/2011 - 15:23
Posts: 928
Location: Thailand
ImA4Wheelr wrote:

POK wrote:

Maybe focal length is 140mm same as I got 2 from DX.

http://dx.com/p/99mm-replacement-glass-lens-for-flashlights-43043

 

Interesting.  Says 80mm in the link, but I’m not surprised it is wrong.  Are they actually 24mm thick as advertized?  If so, they it would see the lens in the OP would have an even longer FL since it is only 19mm thick.   How are the lenses working for you?

“How are the lenses working for you?”

badddddd

ImA4Wheelr
Offline
Last seen: 1 month 5 days ago
Joined: 02/03/2013 - 14:51
Posts: 7935
Location: SC

Sorry to hear that.  Thanks for reporting.  I take it it doesn't focus clearly?

 

I'm starting to like DX, but it seems their line of aspheric lenses is quite sub-par.  Lets hope this FT lens is a good one.

ImA4Wheelr
Offline
Last seen: 1 month 5 days ago
Joined: 02/03/2013 - 14:51
Posts: 7935
Location: SC

Deal Alert.  OP updated

Pulsar13
Pulsar13's picture
Offline
Last seen: 11 months 2 days ago
Joined: 02/05/2012 - 10:23
Posts: 1909
Location: Malaysia

Yowza! 790k from XML2, especially 400k from MTG2 is quite… insane! Especially one you can build at lower budget.

What’s the approximate focal length of this lens?

ImA4Wheelr
Offline
Last seen: 1 month 5 days ago
Joined: 02/03/2013 - 14:51
Posts: 7935
Location: SC

Focal length is about 5.5" (about 14 cm).

Had to get out to try it out.  This lens has to be built into a zoomie because fully focused you need binoculars to see out far enough to to use the hot spot. The hot spot is too small within the range of normal eye sight.  Check you my 20 minute to build light:

ImA4Wheelr
Offline
Last seen: 1 month 5 days ago
Joined: 02/03/2013 - 14:51
Posts: 7935
Location: SC

Here is a beam shot aiming at a 70 foot tall pine tree.  Pine trees love to eat up light.  Distance to the tree is about 250 feet.

RaceR86
RaceR86's picture
Offline
Last seen: 5 years 7 months ago
Joined: 02/22/2012 - 08:32
Posts: 3777
Location: Norway

BLF LED database – collaboration spreadsheet and latest news about where to buy LEDs
http://budgetlightforum.com/node/19342

ImA4Wheelr
Offline
Last seen: 1 month 5 days ago
Joined: 02/03/2013 - 14:51
Posts: 7935
Location: SC

LOL. Yeah, totally surprised me too.  I expected junk for $9.  I'm thinking the issue is that it might focus the image of the die with some artifacts.  Could just be my set up though with the white PVC.  Well, I have to crash for work tomorrow.  Night folks.

B42
B42's picture
Offline
Last seen: 7 months 3 weeks ago
Joined: 03/07/2013 - 21:03
Posts: 1876

Wow, very nice results! But wait a minute…something looks familiar…did you steal jmpaul320’s camera and technique? Wink

Pulsar13
Pulsar13's picture
Offline
Last seen: 11 months 2 days ago
Joined: 02/05/2012 - 10:23
Posts: 1909
Location: Malaysia
B42 wrote:
Wow, very nice results! But wait a minute…something looks familiar…did you steal jmpaul320’s camera and technique? Wink

Hahaha… can’t blame him, that IS a popular technique nowadays! :bigsmile:

At 14cm FL, this FT lens is pretty much the same thing as DX, only $1.10 cheaper. Nice. Quite tempted to try this as well, except that I still have 62mm project lens laying around almost a year… with the project not even starting LOL. Maybe I’ll try 100mm after actually finishing that.

Pages