Aspheric lens for a C8 ?

38 posts / 0 new
Last post

Pages

Dave-H
Offline
Last seen: 1 year 4 months ago
Joined: 11/07/2011 - 15:19
Posts: 119
Location: Surrey, UK
Aspheric lens for a C8 ?

Has anyone fitted an  aspheric lens to a C8 for greater throw?

Is it a worthwhile mod, and indeed can you get an aspheric lens to fit a C8?

srtbrazil
srtbrazil's picture
Offline
Last seen: 6 years 6 months ago
Joined: 07/06/2011 - 08:40
Posts: 134
Location: Brazil

Dave I have the same doubts as you. I´m interested in this lens too.

gcbryan
Offline
Last seen: 4 days 9 hours ago
Joined: 05/07/2010 - 20:42
Posts: 2541
Location: Seattle,WA
It would be worthwhile. People do similar things with Mags all the time. I'm not aware of any off the shelf aspherics with the right diameter and focal length for a simple drop-in though.

I don't have a C8 but do have a HS-802. Is that about the same diameter as a C8? I ground down a larger aspheric so that it would fit that light but focal length is the other issue. I had to muunt the aspheric halfway down the barrel of the head.

I also have a 50 mm aspheric that I haven't used for anything yet. The concept is no different than the DBS or Tiablo aspherics however. I'm still referring to XR-E's however for best results.
how2
Offline
Last seen: 4 years 6 months ago
Joined: 06/01/2010 - 10:26
Posts: 2416
Location: london

Why do it when you can buy a Flood to Zoom from Manafont for $14.90.

I'm not to sure!!! Will they give the same beam pattern?

gcbryan
Offline
Last seen: 4 days 9 hours ago
Joined: 05/07/2010 - 20:42
Posts: 2541
Location: Seattle,WA
I'll let you know in a week or two since I just ordered that! I just depends on the quality of the aspheric that you use and of the host that you put it in as to whether one is better.

When you pick your own host you can pick a better constructed body than most of the cheap zoom lights use. In a twist rather than push/pull light those may work quite well. I have two different twist versions on order.

For the most part however those zoom lights just don't seem to be constructed very well. Until recently there weren't larger sized aspherics in those zoom lights.
agedbriar
Offline
Last seen: 2 months 2 weeks ago
Joined: 04/09/2011 - 18:11
Posts: 642
Location: Slovenia, EU

This lens should fit a C8 class head.

http://www.dealextreme.com/p/44mm-secondary-optics-glass-5-pack-4558

Too bad they are sold as a five-pack only, a bit too many for a first experiment.

I was thinking of trying the same thing, but came across the Small Sun ZY-C10 pictured above, and I have now that one on the way.

robertkoa
Offline
Last seen: 1 year 2 months ago
Joined: 10/12/2011 - 17:03
Posts: 191

GCBrian- will be intersted to see your impressions of the twist zooms when you get them .

 

Which models are they- seems like the twist types which I prefer for stability/quality are more rare than the push pull ,imprecise types.

gcbryan
Offline
Last seen: 4 days 9 hours ago
Joined: 05/07/2010 - 20:42
Posts: 2541
Location: Seattle,WA
robertkoa wrote:

GCBrian- will be intersted to see your impressions of the twist zooms when you get them .

 

Which models are they- seems like the twist types which I prefer for stability/quality are more rare than the push pull ,imprecise types.

They do seem to be more rare. Many who like zoom lights like the fact that will push/pull you can use one hand.

I'm interested more for the throw and I don't want that setting to move so easily when I put the light in my pocket so twist is better.

It now looks like only one is twist as the other was mis-advertised.

The twist model arrived today and here is a link to my review.

http://budgetlightforum.com/node/6017

By the way, this twist model and be used one handed quite easily.
2pts1scn
Offline
Last seen: 2 years 9 months ago
Joined: 06/13/2011 - 21:24
Posts: 143

 FWIW, surplusshed.com has a Jaegers 41mm diam., 35 mm FL for 4.50 US, a Pyrex 44mm diam., 30mm FL for 6.00 US, and a double convex aspheric 44mm diam. 30mm FL for 5.00 US. Shipping is a flat 5.00 for an entire order. More expensive than some, cheaper than others, somewhere in between. Probably good quality; I don't have any of the three myself.

                                                              

 

agedbriar
Offline
Last seen: 2 months 2 weeks ago
Joined: 04/09/2011 - 18:11
Posts: 642
Location: Slovenia, EU

Do those lenses have a flange?

I'm only getting ready for my first aspheric mod, but I think the flange makes the job much easier. I also doubt if a double-convex lens would be suitable for this task.

2pts1scn
Offline
Last seen: 2 years 9 months ago
Joined: 06/13/2011 - 21:24
Posts: 143

 Yes, they do have a flange, which should make grinding to size somewhat easier. I agree about the DCX, although someone in another thread (I haven't searched for it) did use a DCX successfully.

2pts1scn
Offline
Last seen: 2 years 9 months ago
Joined: 06/13/2011 - 21:24
Posts: 143

  "For shipments going to Hawaii, Alaska or countries outside the U.S., we will e-mail shipping option prices for your approval prior to processing your order "  This what they say about shipping outside the US.

agedbriar
Offline
Last seen: 2 months 2 weeks ago
Joined: 04/09/2011 - 18:11
Posts: 642
Location: Slovenia, EU

Speaking of grinding to size: what are the recommended methods?

Chicago X
Chicago X's picture
Offline
Last seen: 5 years 12 months ago
Joined: 07/22/2011 - 16:13
Posts: 4013
Location: See Name

Any specs on these lenses ?

Specifically the BFL, or Back Focal Length is of particular importance. 

http://wardogsmakingithome.org/index.html

War Dogs, Making it Home - Rescue Dogs for Returning Vets

2pts1scn
Offline
Last seen: 2 years 9 months ago
Joined: 06/13/2011 - 21:24
Posts: 143

 The best way that I have found is to use a conventional bench-top grinder, resting the lens flat side down on the provided support in front of the wheel,with a piece of thin cardboard under the lens to prevent scratching. I bring the lens against the wheel and rotate it horizontally as methodically as I can to try to maintain a circular shape. A fairly slow process but not too bad; nonetheless,I hope someone has a better way.

2pts1scn
Offline
Last seen: 2 years 9 months ago
Joined: 06/13/2011 - 21:24
Posts: 143

 ChicagoX, thefirst one (Jaegers 41diam./35FL) has a back FL of 30mm, 15mm center thickness,3mm edge thickness. For the second (Pyrex 44diam.,30 FL ) no back FL given,14 mm center thickness, 2.5 mm edge thickness. The last one, the DCX, again no back FL given, 17 mm center thickness, 3 mm edge thickness. All this from their website, again, I don't yet have any of them. Given the $5.00 flat rate shipping I may order all three for 20.50 rather than one for about 10.00. Spend money to save money.

agedbriar
Offline
Last seen: 2 months 2 weeks ago
Joined: 04/09/2011 - 18:11
Posts: 642
Location: Slovenia, EU

2pts1scn wrote:

 The best way that I have found is to use a conventional bench-top grinder, resting the lens flat side down on the provided support in front of the wheel,with a piece of thin cardboard under the lens to prevent scratching. I bring the lens against the wheel and rotate it horizontally as methodically as I can to try to maintain a circular shape. A fairly slow process but not too bad; nonetheless,I hope someone has a better way.

Wow, if a lens can stand that, then dremelling radially (that's what I had in mind) should be plenty safe.

2pts1scn
Offline
Last seen: 2 years 9 months ago
Joined: 06/13/2011 - 21:24
Posts: 143

 I found dremelling to be very very slow, but I think it would have worked if I was more patient. The grinding wheel does create excessive heat if the lens isn't kept moving or "backed off" periodically.

gcbryan
Offline
Last seen: 4 days 9 hours ago
Joined: 05/07/2010 - 20:42
Posts: 2541
Location: Seattle,WA
I don't have a bench grinder or a Dremel tool but for a while I had access to a friends bench grinder and I did it exactly as mentioned above.

It does get hot so you have to back off every now and then and you need to constantly get turning it. It's not hard to do however.

I think it would be hard to do with a Dremel with the smaller head size but it's worth a try.
agedbriar
Offline
Last seen: 2 months 2 weeks ago
Joined: 04/09/2011 - 18:11
Posts: 642
Location: Slovenia, EU

It helps to know that one doesn't have to be too concerned about cracking the lens or chipping its edges.

I thought it was a very delicate job.

Chicago X
Chicago X's picture
Offline
Last seen: 5 years 12 months ago
Joined: 07/22/2011 - 16:13
Posts: 4013
Location: See Name

I have had good luck covering the entire lens with a thick layer of masking tape, then cutting out the areas to be ground with a hobby knife. 

I have only used a dremel, albeit with smaller lenses than the one discussed here.  The grinder sounds like a much faster method. 

http://wardogsmakingithome.org/index.html

War Dogs, Making it Home - Rescue Dogs for Returning Vets

gcbryan
Offline
Last seen: 4 days 9 hours ago
Joined: 05/07/2010 - 20:42
Posts: 2541
Location: Seattle,WA
agedbriar wrote:

It helps to know that one doesn't have to be too concerned about cracking the lens or chipping its edges.

I thought it was a very delicate job.

I had no previous experience either. It turns out that glass is fairly soft so no issues with cracking or chipping.

My main concern was (as is) to wear a mask and to use the grinder where you can clean up the area easily. Keep the area around it clear so that powered glass dust don't get on things.
gcbryan
Offline
Last seen: 4 days 9 hours ago
Joined: 05/07/2010 - 20:42
Posts: 2541
Location: Seattle,WA
agedbriar wrote:

It helps to know that one doesn't have to be too concerned about cracking the lens or chipping its edges.

I thought it was a very delicate job.

I had no previous experience either. It turns out that glass is fairly soft so no issues with cracking or chipping.

My main concern was (as is) to wear a mask and to use the grinder where you can clean up the area easily. Keep the area around it clear so that powered glass dust doesn't get all over everything. I wouldn't want this dust in my lungs either!
viffer750
Offline
Last seen: 2 years 3 months ago
Joined: 08/15/2011 - 10:29
Posts: 514
Location: Hungary

I use a hand grinder with thick disk usually.  I place the lens to a vice bench between two pieces of thick rubber.

I just say, it cuts just knife trough butter, you can make it very fast. I use safety glassesCool and protective gloves of course.

 

 

unique engrish language... Smile

 

feilox
Offline
Last seen: 1 year 2 months ago
Joined: 07/21/2012 - 04:42
Posts: 839
Location: wisconsin, usa

So nothing is a perfect fit? kinda sucks.

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

Werner
Werner's picture
Offline
Last seen: 11 months 2 weeks ago
Joined: 10/19/2012 - 15:00
Posts: 3677
Location: Germany

I pull this back from the grave…

Was somebody successful with a aspheric c8?
I have a xml c8 laying around and thought of putting a lens on it.

kevind43
Offline
Last seen: 1 year 6 months ago
Joined: 01/24/2012 - 17:47
Posts: 462
Location: ny

i got four from surplus shed awhile back. every thing that was close in diameter and focal length, none were a drop in. needed extensive work to lens or housing. will post part numbers that didn’t work if you like.

Werner
Werner's picture
Offline
Last seen: 11 months 2 weeks ago
Joined: 10/19/2012 - 15:00
Posts: 3677
Location: Germany

How was the result? Much smaller hotspot?

Omega_17
Offline
Last seen: 2 days 21 hours ago
Joined: 06/02/2013 - 16:56
Posts: 854
Location: France

Still no replies since 2011… Sad

I have found a 40mm convex glass and I bought it : http://www.ebay.com/itm/1pc-High-Power-LED-40mm-convex-lens-optical-glass-led-lens-/180916494907?pt=LH_DefaultDomain_0&hash=item2a1f76a23b

Just the same diameter as the reflector of the C8. I tried with a cheap 30mm convex plastic from another light and the result was not so bad but hardly brighter.
The new XML-2 LED pattern make it way better for aspheric.

Dedome is better for an aspheric thrower ?

Ramblings
Ramblings's picture
Offline
Last seen: 18 hours 10 min ago
Joined: 01/09/2013 - 04:05
Posts: 755
Location: Australia

Give it a try and find out. Smile

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

LSX
LSX's picture
Offline
Last seen: 1 day 18 hours ago
Joined: 04/23/2013 - 08:38
Posts: 1444
Location: Perth, Australia

I bought the aspheric zooming C8 host from Wallbuys a little while ago. I put a de-domed XP-G2 1A in it. Very tight beam and throws pretty well but the optic isn’t very good quality so I didn’t do anything more with it.

Here is my build thread… Zooming C8

Pages