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  1. #1
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    fresnel lenses for sale

    Hi guys,

    Since you guys often are concerned about weight, I thought I could help a bit with some optics.
    I've seen many of you using aspherics to get tight beams, however, these are quite heavy.

    For my other hobby, scuba diving, I've been using fresnel lenses because they do not take much space (2mm thick).
    Another advantage is that they only weigh a few grams.
    Since I needed only a few, but it was more interesting to get bigger quantities regarding shipping costs, I have some lenses for sale if you are interested.

    I've been looking around to find the best fresnel lenses and I'm quite happy with these for my diving needs. Perhaps you can use them too.

    Currently I have 2 types of fresnel lenses for sale, 25mm and 50mm diameter lenses. Both lenses have short focal lengths so capture most of the light. (I can get 38mm fresnel lenses as well if there's enough interest)

    The 25mm lens is quite similar to the ahorton lens that many of you probably know, just much lighter. you get the same beam angle as with the ahorton lens.
    The 50mm lens gives a tighter beam (slightly longer focal length, so smaller magnification) and I've used this lens mainly in dive lights from Green Force and in maglites. these can be easily added without modifications.

    If you search Budgetlightforum or cpfmarketplace for my username, you can find some examples of what I and others have done with these lenses. (not sure if I can post links here)

    Since I have these lenses at home, and can ship them cheaply worldwide, let me know if someone is interested.
    I ask 6 euro for the 25mm lenses and 7.5 euro for the 50mm lenses and 1.5 euro for international shipping. I can ship multiple lenses for the same price. For larger quantities, send me an email and I can see if I can get you a better price.
    You can pay via paypal at [myusername]@gmail.com (replace first part of email address by my username), or drop me an line if you have questions.

    best regards,
    Johan

  2. #2
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    Interesting stuff. Johan, where do you come from?

  3. #3
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    Hi,

    I live in Belgium in Europe.

    Johan

  4. #4
    My Rusty Knee
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    I'd be interested in 2 x 38mm if you had them for my Easy2LED lights
    What exactly is a rigid hard tail?

  5. #5
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    I have 1 left, and can get new, but might take a week or 2 to get here. price is 7 for the 38mm lenses.

    Edit, I just looked in the box, and apparently still had 2 left, so if you're quick, they are yours.
    I would be interested to see how they work with these housings. Feel free to post pictures in this thread.

    Johan
    Last edited by jspeybro; 11-24-2013 at 05:01 AM. Reason: 2 lenses instead of 1 available

  6. #6
    My Rusty Knee
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    Ok cool. Will arrange payment ASAP when I get back to my computer this eve.

    Will try and post pics

    sent from my phone, apologies for any typos.
    What exactly is a rigid hard tail?

  7. #7
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    Hi Johan,

    Payment sent .

    Stu
    What exactly is a rigid hard tail?

  8. #8
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    Thanks, the lenses are packed so will be shipped tomorrow morning.

    Best regards,
    Johan

  9. #9
    My Rusty Knee
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    Ace

    Cheers
    What exactly is a rigid hard tail?

  10. #10
    My Rusty Knee
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    Hi Johan,

    My Lenses arrived safely today, thank you very much

    I have just done a very quick and dirty test with my Easy2led with MTG2 LED. I simply swapped the glass lens with the fresnel leaving the reflector on place. the reflector is a Ledil minnie medium angle.

    This could actually be a good long term option although I am going to experiment. with this setup you get a slightly de-focussed die shape with an even smooth hexagon with an even dimmer spill. I am going to try this on my helmet. the hot spot is bigger than that of my solarstorm x2. peak intensity looks less, but the hot spot has more light in its bigger area so should mean less head turning to aim the light.

    I will try and take some pics at the weekend.

    Just to clarify, I have placed the lens flat side rear wards, is that best, does it matter? If the other way is possible it might be better for cleaning mud off the lens.

    Stu
    What exactly is a rigid hard tail?

  11. #11
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    Hi Stuart,

    yes, the flat side should point to the LED and the grooves should point away from it.

    would be interesting to see what you did with the ledil reflector and lens combination.

    regards,
    Johan

  12. #12
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    Did you manage to take some pics?

  13. #13
    My Rusty Knee
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    Hi Johan,

    I haven't yet...I will try at the weekend . Apologies.

    Stu
    What exactly is a rigid hard tail?

  14. #14
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    no worries, I'm just curious ;-)

  15. #15
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    38mm lenses are back in stock. 7 per lens

    Johan

  16. #16
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    Hi Johan
    could I have 2 of each please to play around with

  17. #17
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    troutie, PM sent

  18. #18
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    Johan Euros sent
    got ideas for another stupid OTT bar light

  19. #19
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    Thanks, lenses will be on its way today.
    Looking forward to your projects.

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