DIY Fluid Goggles

[watts]

Im definetly interested in about 5 sets in the 100 for Sydney Australia if we can work out payment and postage.
It would be great if everyone could post some pics of their creations and say how they affixed the lenses in place and what brand of goggles used .

Cheers Nathan Watts

[OceanMan]

Ok guys it is now a world command and not only a European command. If I can ship the lenses to Finland or Israel why not to Australia or USA ? Let's go for it. The cost of shipment from France to Australia or USA or else is not that much, depending on the weight. For 0,1 Kg = 100 g the maximum price is 2,85 € ; for 200 g it is ~8 € . I don't know exactly the weight of lenses.

If you are interested please send me a private message with your email so I can create a mailing list with those who want to buy lenses. Then we will be able to organize the command.

[DeepThought]

Send.

Now if we could only do the same for paradisias....

[Ruffdiver]

Hello,

I´m a german freediver and I´m interested to order 4 lenses.
I hope to get the lenses.

Deeply,
Andy Güldner (19)
"German Young Gun Freediver"

[OceanMan]

I have sent you a private message.

We are closer and closer to the 100 lenses if we haven't reach it yet. Please feel free to contact me to join the command.

[donmoore]

Okay, this might be a dumb question by someone with little understanding of optics, but here it is.

When making fluid goggles why are we using PCX lenses, which stands for Plano Convex Lenses and, which means to use them for magnification we have to look through from flat side and convex side is against the inside of the goggle lense, which means we have to build stands off and fool around with mounting them, etc.; when we could use PCV (Plano Concave) lenses and just glue the flat side to the goggle lenses with some non-yellowing optical glue like the optical shops do for prescription dive masks?
don

[donmoore]

Maybe I found the answer to my own question. I saw these statements on an optical web site:

“Plano-Convex Lenses (PCX) have one flat and one outward curved face and a positive focal length. They can magnify or condense.”

“Plan-concave lenses (PCV) have one flat side and one inward curved face and a negative focal length. The are use for image reduction or to spread light”

So if I understand it, if you look through the inward curved side of a PCV lense you get image reduction, but from the other direction they are made to spread light, not magnify sight. You probably only see blurry enlargement with lots of light.

PCX lenses can be used for image magnification or reduction based on which way you look through them.

But I wonder if the gluing idea could still work by doing what bevan dewar did on page three of this thread and attach the PCX lense to the outside of goggle lense, but instead of trying to use hold offs to allow water between the two lenses and then have to deal with air bubbles and cleaning issues, just glue them together with no air space.

One major problem is the small diameter of the lenses, 20mm. When you go up in diameter of pre-manufactured lenses the focal point goes way past 20mm.
don

[Mlaen]

Just one more question that bugs me and can't find answer for it:
Is the cost 4.65Eur for one lense or for pair??

[OceanMan]

The cost of one (1) Hiteck lens is 4,62$ according to their website.

[Bill]

Don
I've been waiting for someone else to answer you. Optics is not my best subject.

Concave lenses will make focuse worse.

"PCX lenses can be used for image magnification or reduction based on which way you look through them."

It doesn't care which way you look through them, they act the same. The flat side allows you to mount them inside or outside the goggles. If you mount them inside, you will be able to see in and out of the water (if the goggles are filled with saline solution). On the outside, you can't see until you're face is submerged.
Aloha
Bill

[donmoore]

Thank you Bill, that helps a lot. Besides being able to see outside of the water, mounting on the inside takes up some volume. Less fluid to use! I’m definitely trying the optical glue. Most of it is UV cured, which I believe means it will cure in the sun in 5 minutes if you don’t have a $1,500 UV gun to cure it in 5-seconds.

Okay, here a bomb shell for you U.S.A. fluid goggle makers. First and overstock PCX lenses for cheap right here in the U.S.A. No big quantities have to be purchased and no shipping arrangements. I just found this site yesterday and have noticed their stock has changed since then. Today they have at least one 21.5 diameter with 20mm focal PCX for the price of $9 plus shipping. Yesterday they had some 21 mm diameter with 20mm PCX.s.

If I understand it, it’s the focal point of 20 that works. A slightly larger diameter only means you get a slightly larger field of view. Seems like a lot of what they have are left-overs from custom-made stuff, because the sizes are not standard.
www.anchoroptics.com
don

[efattah]

The focal length of the lens in air doesn't tell you the focal length in water. The lens in question has a 20mm focal length in AIR, but the focal length in water depends on the refractive index of the material.

Therefore 'swapping' with another lens of focal length 20mm won't work at all.

Putting the lens on the outside of the goggle creates a huge magnification.

A plano concave lens can be used in a fluid goggle to correct your vision, but only if the refractive index of the lens material is less than water.

The statement that a plano concave lens has a negative focal length is only true if the lens has a higher refractive index than the surrounding medium.

I have been building fluid goggles for 7 years; if there were an easier, simpler method, I would have already used it.

Early goggles had the lenses outside the goggle. I also built fluid goggles with meniscus lenses, and those had lenses made of cleartran zinc sulfide (index = 2.35), resulting in the lowest magnification and a GIANT field of view, unfortunately they were also ridiculously expensive. Those lenses were molded into a liquid plastic on the inside of the goggle, making the internal fluid volume needed to fill the goggle near zero.

[Jon]

If we get this order through I have an idea that I've been thinking over for some time.

One of the optical scuba companies is just down the road and they have made me many a RX face mask over the years- they even used to make my glasses for me before I had LASIK surgery.

I know that I have seen flat glass RX swimming goggles in the place before and I know the guy can grind, or glue, just about anything- you should see the tri-focals he made for my father-in-law's full face mask.

I believe that if scrubbing the scuzz off the inside of a plastic swimming goggle to glue on the lens is the hard part, then starting out with an already clean glass blank to glue the lens onto should make that step a whole lot easier.

It would also mean that you don't have to worry if Speedo will still make a certain model of goggle next year since the RX swimming goggles have been standard for some time. It also means I could get a clear lens and not settle for a smoked- to get the clear ones cost close to $400.

Not positive if it will work, but I am willing to shuck out a few bucks to let a guy who's been at it for over 30 years to give it a try.

Jon

[donmoore]

You’re right, this is difficult stuff, but if you’re not selling them anymore or my weird shaped eye sockets won’t fit normal goggles, then this is my only way. Thanks for sharing all your knowledge with us Eric.

Well if Hi-Tech’s LENS PCX 20 x 20 UNCTD TS is the same thing as Edmund’s then the material used is SF11, which according to Edmund’s chart at http://www.edmundoptics.com/TechSupp...?articleid=259 has a refractory index of 1.785. www.anchoroptics.com doesn’t show the material they are made out of. Probably because they assume their users are using them in air. But I imagine you could e-mail or call them and find out. Do coatings chance the refractory index?

Water index is 1.33 according to http://hyperphysics.phy-astr.gsu.edu...les/indrf.html. Doesn’t look like Edmund has lense material with index of less than water so plano concave lens do not look promising. Bummer! Mounting would have been so easy!

The two most common materials seem to be BK7 with index of 1.517 and SF11 1.785. So if the refractory index is higher, I suppose you need less focal length or magnification. Is that correct?

In looking at PCX lenses with 20mm focal points on Hi-Tech’s site, all of them are made out of SF11, so it must be a material that works good for producing that focal point and there is probably a good chance www.anchoroptics.com either has or will have 20mm focal point PCX lenses made from SF11.

www.anchoroptics.com also has Meniscus lenses for extremely low prices.
don

[efattah]

SF11 is pretty cheap, has a high index and a good abbe number (low chromatic abberration).

I have currently 100 lens blanks (un-ground) of SFL57, with an index of 1.85.

The original fluid goggles were made with single crystal cleartran zinc sulfide with an index of 2.35, but very bad chromatic abberration.

The higher the index, the flatter the lens, which means you get three advantages:
1. Less distortion in the peripheral vision
2. Less magnification
3. Bigger lens is possible for wider field of view

The only material with a lower index than water is Teflon AF, with an index of 1.29, which is too close to water to be of much use. The other alternative is it use air as the lens (index 1.00) and shape the water around it (i.e. make a hollow concave lens). But, there is a chance it will implode at depth, sending breaking glass into your eyes and blinding you for life.

Coatings have no effect on the lens power.