SUN GLASSES

DO NOT FLY WITH NON POLORIZED LENS!
by doing so you trick your eye into opening wider because of the
shade. Remember polorization is used to protect from UV light. If
you open your eye wider by non polarized glass you expose your
eye to that UV light. You will damage your eye much quicker. It is
not a function of can you see your instruments or not. Do not be
mislead into this kind of thinking......
Most glider canopies are not made with polorized protection.

I know this has been discussed to death in previous threads bit I find it interesting/humorous to see DO NOT use polarized lenses and DO NOT use NON polarized in the same thread. Again. I use 'em.

At 11:02 13 June 2013, Doug Mueller wrote:
DO NOT FLY WITH NON POLORIZED LENS!
by doing so you trick your eye into opening wider because of the
shade. Remember polorization is used to protect from UV light.
If
you open your eye wider by non polarized glass you expose your
eye to that UV light. You will damage your eye much quicker. It
is
not a function of can you see your instruments or not. Do not be
mislead into this kind of thinking......
Most glider canopies are not made with polorized protection.


That's ridiculous. That advice is valid only for the sort of cheap
children's or other useless coloured lenses that have little or no
UV filtering. All aviation, and other general and sporting use,
non-polarised lenses from reputable manufacturers have a high
level of UV filtering.

Suggestion: Buy a pair of polarized cheap sun glasses (sounds like a ZZ Top song). Then try them in your cockpit. If you like them, only they buy a nice polarize pair.

If I remember correctly in aviation catalogs I only see non-polarized. I read at Sporty's the following;

--- Why we don't sell polarized sunglasses ---
Many sunglasses today are polarized, meaning they use an optical filter to reduce glare. While this is fine for fishing or driving, it's a bad idea for pilots. That's because many cockpit instruments and glass panels have polarized faces, and polarized sunglasses will render these unreadable. In addition, the iPad screen will be blacked out in portrait orientation when wearing polarized sunglasses. Sporty's sells a wide variety of high quality sunglasses that do an excellent job of reducing glare--but without polarization.
----------------------------------------------

I use non-polarized Serengeti's. The better question is ... what tint is recommended for the lenses? Brown? Green? Gray? Yellow? Chartreuse?

- John

JohnDeRosa wrote:

I use non-polarized Serengeti's. The better question is ... what tint is
recommended for the lenses? Brown? Green? Gray? Yellow? Chartreuse?


Rose, of course. You must view the world through rose-colored glasses to
confidently fly cross country without an engine.

P7 unit

P7 has the best answer...

But Let's step back to facts, shall we?

Polarized lenses literally block light, unless the light-waves are
oriented at a specific angle to the lens.

Almost all LCDs (including PDAs, cell-phones, iPads, and even simple
displays like Cambridge *-NAV devices or digial variometers) have 1 or
2 polarized screens, as part of how they work. See he
http://en.wikipedia.org/wiki/Liquid-crystal_display

Stacking multiple polarizing filters in the proper orientation lets
light pass through. But stacking them in the wrong orientation causes
the light passing through the first filter to be BLOCKED by the
second.

Your polarized sunglasses _are_ a "second filter", sitting between
your eyeballs and the LCD screens in your cockpit. Ergo, if the
orientation of your sunglasses' polarized surface is not near the same
angle of your electronic displays, the visibility of your instruments
will be negatively impacted. Here are two video demonstrations of
this:
http://www.youtube.com/watch?v=GkLBMAY406Q
http://www.youtube.com/watch?v=HcQWAqL2JUw

Polarized sunglasses are not all manufactured the same; and even
different batches of the same sunglasses may not always have the
orientation to the polarized lenses - don't assume that because your
glasses work for you, that you can recommend them to others or that
you can simply buy another pair of the same, and have them work
identically. Additionally, just because you find glasses that may work
with _your_ cockpit instruments and canopy, do _not_ assume that it
will work with _all_ instruments or canopies. Finally, don't assume
that all of your instrument displays have the same polarization on
their screens. I have polarized lenses that work fine when viewing
some of my instruments, but not with others (unless you rotate the
glasses 90-degrees). Also, these polarized sunglasses worked fine
with my DG-300 canopy, but created horrible moire & checkerboard
patterns on a couple of Diamond DA-20 rental aircraft canopies.

If you're going to fly with a lot of cockpit electronics, I strongly
recommend against polarized lenses because you don't want to be
distracted or fumbling with your instruments because of this effect.
There are plenty of effective non-polarized sunglasses out there that
give you good visibility and protection.

Lastly, if you're going to be flying in a club or rental environment,
where you switch ships with any regularity, do NOT assume that
polarized sunglasses which work in one cockpit will work in another.

--Noel

On Thursday, June 13, 2013 3:12:14 PM UTC-7, noel.wade wrote:
P7 has the best answer...



But Let's step back to facts, shall we?



Polarized lenses literally block light, unless the light-waves are

oriented at a specific angle to the lens.



Almost all LCDs (including PDAs, cell-phones, iPads, and even simple

displays like Cambridge *-NAV devices or digial variometers) have 1 or

2 polarized screens, as part of how they work. See he

http://en.wikipedia.org/wiki/Liquid-crystal_display



Stacking multiple polarizing filters in the proper orientation lets

light pass through. But stacking them in the wrong orientation causes

the light passing through the first filter to be BLOCKED by the

second.



Your polarized sunglasses _are_ a "second filter", sitting between

your eyeballs and the LCD screens in your cockpit. Ergo, if the

orientation of your sunglasses' polarized surface is not near the same

angle of your electronic displays, the visibility of your instruments

will be negatively impacted. Here are two video demonstrations of

this:

http://www.youtube.com/watch?v=GkLBMAY406Q

http://www.youtube.com/watch?v=HcQWAqL2JUw



Polarized sunglasses are not all manufactured the same; and even

different batches of the same sunglasses may not always have the

orientation to the polarized lenses - don't assume that because your

glasses work for you, that you can recommend them to others or that

you can simply buy another pair of the same, and have them work

identically. Additionally, just because you find glasses that may work

with _your_ cockpit instruments and canopy, do _not_ assume that it

will work with _all_ instruments or canopies. Finally, don't assume

that all of your instrument displays have the same polarization on

their screens. I have polarized lenses that work fine when viewing

some of my instruments, but not with others (unless you rotate the

glasses 90-degrees). Also, these polarized sunglasses worked fine

with my DG-300 canopy, but created horrible moire & checkerboard

patterns on a couple of Diamond DA-20 rental aircraft canopies.



If you're going to fly with a lot of cockpit electronics, I strongly

recommend against polarized lenses because you don't want to be

distracted or fumbling with your instruments because of this effect.

There are plenty of effective non-polarized sunglasses out there that

give you good visibility and protection.



Lastly, if you're going to be flying in a club or rental environment,

where you switch ships with any regularity, do NOT assume that

polarized sunglasses which work in one cockpit will work in another.



--Noel

Good points.
I guess it all boils down to "it depends". Polarized glasses always worked for me in the gliders I flew, but I agree this is not always going to be the case.
So the solution is to have a spare non polarized glasses with you in case there is an issue.

Ramy

At 00:11 14 June 2013, Ramy wrote:
On Thursday, June 13, 2013 3:12:14 PM UTC-7, noel.wade
wrote:
P7 has the best answer...



But Let's step back to facts, shall we?



Polarized lenses literally block light, unless the light-waves
are

oriented at a specific angle to the lens.



Almost all LCDs (including PDAs, cell-phones, iPads, and
even simple

displays like Cambridge *-NAV devices or digial
variometers) have 1 or

2 polarized screens, as part of how they work. See he

http://en.wikipedia.org/wiki/Liquid-crystal_display



Stacking multiple polarizing filters in the proper orientation
lets

light pass through. But stacking them in the wrong
orientation causes

the light passing through the first filter to be BLOCKED by
the

second.



Your polarized sunglasses _are_ a "second filter", sitting
between

your eyeballs and the LCD screens in your cockpit. Ergo, if
the

orientation of your sunglasses' polarized surface is not near
the same

angle of your electronic displays, the visibility of your
instruments

will be negatively impacted. Here are two video
demonstrations of

this:

http://www.youtube.com/watch?v=GkLBMAY406Q

http://www.youtube.com/watch?v=HcQWAqL2JUw



Polarized sunglasses are not all manufactured the same;
and even

different batches of the same sunglasses may not always
have the

orientation to the polarized lenses - don't assume that
because your

glasses work for you, that you can recommend them to
others or that

you can simply buy another pair of the same, and have
them work

identically. Additionally, just because you find glasses that
may work

with _your_ cockpit instruments and canopy, do _not_
assume that it

will work with _all_ instruments or canopies. Finally, don't
assume

that all of your instrument displays have the same
polarization on

their screens. I have polarized lenses that work fine when
viewing

some of my instruments, but not with others (unless you
rotate the

glasses 90-degrees). Also, these polarized sunglasses
worked fine

with my DG-300 canopy, but created horrible moire &
checkerboard

patterns on a couple of Diamond DA-20 rental aircraft
canopies.



If you're going to fly with a lot of cockpit electronics, I
strongly

recommend against polarized lenses because you don't
want to be

distracted or fumbling with your instruments because of this
effect.

There are plenty of effective non-polarized sunglasses out
there that

give you good visibility and protection.



Lastly, if you're going to be flying in a club or rental
environment,

where you switch ships with any regularity, do NOT assume
that

polarized sunglasses which work in one cockpit will work in
another.



--Noel

Good points.
I guess it all boils down to "it depends". Polarized glasses
always worked
for me in the gliders I flew, but I agree this is not always going
to be
the case.
So the solution is to have a spare non polarized glasses with
you in case
there is an issue.

Ramy

Polarised sunglasses should genarally be expected to have
vertical polarization because the whole point about reducing
glare from water surfaces etc is that the light reflected of the
surface to the eye tends to be polarised horizontally.

On another topic - genuine question - do polarised lenses made
without a UV absorbing tint, and without a UV absorbing lens
material such as polycarbonate, reduce UV transmission more
than in proportion to the reduction in general light
transmission?

John Galloway

At 11:02 13 June 2013, Doug Mueller wrote:
DO NOT FLY WITH NON POLORIZED LENS!
by doing so you trick your eye into opening wider
because of the
shade. Remember polorization is used to protect
from UV light. If
you open your eye wider by non polarized glass you
expose your
eye to that UV light. You will damage your eye much
quicker. It is
not a function of can you see your instruments or
not. Do not be
mislead into this kind of thinking......
Most glider canopies are not made with polorized
protection.


Er no, actually. Polarised sunglasses block a portion
of the incident light according to how it is polarised,
not by wavelength. Reflected light is partly polarised,
which is why polarised sunglasses reduce glare.

UV protection is accorded by the tinting medium.
There are plenty of substances out there that block
UV, just as there are tints that block other
wavelengths (hence coloured lenses).

There are a number of standards around for
manufacture of sunglasses based on opacity to UV
(no agreed international standard yet), including an
EN standard in Europe and an ANSI standard in the
US. These specify the maximum transmittance in the
UV part of the spectrum as a percentage of the
transmittance in the visible part.

Naturally your eyes will open wider if the amount of
visible light getting to them drops- the point is that a
very much less of the light getting through is UV.

I don't know about your part of the world, but in
Europe most good sunglasses are sold with a CE
mark indicating that 95% of radiation at 380Nm is
blocked.

None of this has anything to do with polarisation.

In short, check the specified UV transmittance.
Polarisation is just a personal preference.

At 11:02 13 June 2013, Doug Mueller wrote:
DO NOT FLY WITH NON POLORIZED LENS!
by doing so you trick your eye into opening wider because of the
shade. Remember polorization is used to protect from UV light. If
you open your eye wider by non polarized glass you expose your
eye to that UV light. You will damage your eye much quicker. It is
not a function of can you see your instruments or not. Do not be
mislead into this kind of thinking......
Most glider canopies are not made with polorized protection.


Absolute Nonsense. The UV that is damaging to eyes is that with a
wavelength less than 320nm. Looking at the chart on the Zeiss website here


http://tinyurl.com/qxfa6kj

you will see that nearly all the light below 500nm is blocked by the skylet
fun tint.

Furthermore, depending upon the type of perspex, your canopy will cut UV
below 400nm by a further 99%.