Looking for an underwater magnifying glass or lens

Does anyone have experience of what works well in seawater as a
magnifying lens or glass, e.g. to observe pygmy seahorses and other
diminutive creatures?

Thanks in advance ....

Tony

mountsiders@googlemail.com wrote:

> Does anyone have experience of what works well in seawater as a
> magnifying lens or glass, e.g. to observe pygmy seahorses and other
> diminutive creatures?
>
> Thanks in advance ....

There was one from Poseidon, Sweden. I don't see it in my
actual files, sorry. AFAIK the price tag was about 400 USD eqv.

It had illumination, and consisted of several glas/gas layers.
Matthias

mountsiders@googlemail.com wrote:
> Does anyone have experience of what works well in seawater as a
> magnifying lens or glass, e.g. to observe pygmy seahorses and other
> diminutive creatures?
>
> Thanks in advance ....
>
> Tony

Hi Tony,

I'm using a low tech, dirt cheap, 4-inch magnifying glass which
provides a doubling of image size.

It's large enough to allow both eyes to view the object at the same
time.

They can be purchased in bargain stores for about one or two dollars.

A hole can be drilled in the plastic handle to attach a wrist lanyard.
Non-corroding plastic frame.

Here's a site with an image of a similar magnifying glass..

http://bestsource.en.alibaba.com/pro...ing_Glass.html

HTH.

Dave C

PURE TALC: Source, supplier of unscented, oil-free, USP grade PURE
TALC, ideal for use on drysuit latex seals. If interested, please see
my talc offerings on eBay (eBay ID: dave4868). Thank you!

Dave C wrote:

> mountsiders@googlemail.com wrote:
>
>>Does anyone have experience of what works well in seawater as a
>>magnifying lens or glass, e.g. to observe pygmy seahorses and other
>>diminutive creatures?
>>
>>Thanks in advance ....
>>
>>Tony
>
>
> Hi Tony,
>
> I'm using a low tech, dirt cheap, 4-inch magnifying glass which
> provides a doubling of image size.

Perfect.
Under water?

Matthias

Matthias Voss wrote:
> Dave C wrote:
>
> > mountsiders@googlemail.com wrote:
> >
> >>Does anyone have experience of what works well in seawater as a
> >>magnifying lens or glass, e.g. to observe pygmy seahorses and other
> >>diminutive creatures?
> >>
> >>Thanks in advance ....
> >>
> >>Tony
> >
> >
> > Hi Tony,
> >
> > I'm using a low tech, dirt cheap, 4-inch magnifying glass which
> > provides a doubling of image size.


> Perfect.
> Under water?
>
> Matthias

Yes, IMHO, since there is only one refractory substance, the water.
Crystal clear.

Dave C

"Dave C" <dcalderbank@top.monad.net> wrote in message
news:1158008354.479031.90800@q16g2000cwq.googlegro ups.com...
>
> mountsiders@googlemail.com wrote:
> > Does anyone have experience of what works well in seawater as a
> > magnifying lens or glass, e.g. to observe pygmy seahorses and other
> > diminutive creatures?
> >
> > Thanks in advance ....
> >
> > Tony
>
> Hi Tony,
>
> I'm using a low tech, dirt cheap, 4-inch magnifying glass which
> provides a doubling of image size.

Me too, only mine isn't 4 inches across and I can still see through it with
both eyes. I'd also estimate that it magnifies more than double the size.

I got my first one in Malaysia. It's the best and only cost me about $5.
Since then I've been picking up spares at the dollar store. When I go on my
trips, there's always someone that admires my little toy and so I give them
the one I got at the dollar store.

>
> It's large enough to allow both eyes to view the object at the same
> time.
>
> They can be purchased in bargain stores for about one or two dollars.
>
> A hole can be drilled in the plastic handle to attach a wrist lanyard.
> Non-corroding plastic frame.
>
> Here's a site with an image of a similar magnifying glass..
>
> http://bestsource.en.alibaba.com/pro...ing_Glass.html
>
> HTH.
>
> Dave C
>
> PURE TALC: Source, supplier of unscented, oil-free, USP grade PURE
> TALC, ideal for use on drysuit latex seals. If interested, please see
> my talc offerings on eBay (eBay ID: dave4868). Thank you!
>

Dave C wrote:

> Matthias Voss wrote:
>
>>Dave C wrote:
>>
>>
>>>mountsiders@googlemail.com wrote:
>>>
>>>
>>>>Does anyone have experience of what works well in seawater as a
>>>>magnifying lens or glass, e.g. to observe pygmy seahorses and other
>>>>diminutive creatures?
>>>>
>>>>Thanks in advance ....
>>>>
>>>>Tony
>>>
>>>
>>>Hi Tony,
>>>
>>>I'm using a low tech, dirt cheap, 4-inch magnifying glass which
>>>provides a doubling of image size.
>
>
>
>>Perfect.
>>Under water?
>>
>>Matthias
>
>
> Yes, IMHO, since there is only one refractory substance, the water.
> Crystal clear.
>

But there are two refractory surfaces which's influence
cancel each other.

Unless there is an airspace in between.
Like in your mask.

Matthias

Matthias Voss wrote:
> Dave C wrote:
>
> > Matthias Voss wrote:
> >
> >>Dave C wrote:
> >>
> >>
> >>>mountsiders@googlemail.com wrote:
> >>>
> >>>
> >>>>Does anyone have experience of what works well in seawater as a
> >>>>magnifying lens or glass, e.g. to observe pygmy seahorses and other
> >>>>diminutive creatures?
> >>>>
> >>>>Thanks in advance ....
> >>>>
> >>>>Tony
> >>>
> >>>
> >>>Hi Tony,
> >>>
> >>>I'm using a low tech, dirt cheap, 4-inch magnifying glass which
> >>>provides a doubling of image size.
> >
> >
> >
> >>Perfect.
> >>Under water?
> >>
> >>Matthias
> >
> >
> > Yes, IMHO, since there is only one refractory substance, the water.
> > Crystal clear.
> >
>
> But there are two refractory surfaces which's influence
> cancel each other.

> Unless there is an airspace in between.
> Like in your mask.
>
> Matthias

Your explanation makes more sense, Matthias, thanks for the correction.

Dave C

mountsiders@googlemail.com wrote:
> Does anyone have experience of what works well in seawater as a
> magnifying lens or glass, e.g. to observe pygmy seahorses and other
> diminutive creatures?
>
> Thanks in advance ....
>
> Tony
>

As others have mentioned, any el chepo dollar store magnifying glass
will work. The exact magnification you'll get underwater will be
different then on land. Generally speaking, glass should work better
then plastic lenses, as the refractive index of glass tends to be more
different from water then most plastics.

Bryan

Bryan Heit wrote:

> mountsiders@googlemail.com wrote:
>
>> Does anyone have experience of what works well in seawater as a
>> magnifying lens or glass, e.g. to observe pygmy seahorses and other
>> diminutive creatures?
>>
>> Thanks in advance ....
>>
>> Tony
>>
>
> As others have mentioned, any el chepo dollar store magnifying glass
> will work. The exact magnification you'll get underwater will be
> different then on land. Generally speaking, glass should work better
> then plastic lenses, as the refractive index of glass tends to be more
> different from water then most plastics.
>
> Bryan

Ah, a good explanation finally!

BTW, some plastics, notably plexiglass have almost the identicle index of
retraction as water. So those would not function at all. In fact it can
get so bad that plexiglass is virtually invisible underwater (spoken by
one who had to find a plexiglass sheet dropped off a dock ... it had to
be done by feel).