Polarizers?

jerry12953 said:
A polariser can make an awful lot of difference to a landscape image.

Haze is another thing altogether. A polariser will have difficulty cutting through haze. As someone says above haze is particles of crap suspended in the atmosphere.

An easy way of identify when your polariser will work most effectively is to look at your shadow. If you're pointing the camera at 90 degrees to your shadow it will be most effective; but even then atmospheric conditions will dictate how much it will work. A polariser just doesn't work with the sun behind you.

On dull days it will remove reflections from foliage etc. It will also remove reflections from wet rocks , etc, around streams and rivers.

Excellent piece of kit!
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Well for landscapes the polariser has limited use if you believe at midday in summer (sun 90 degrees to the camera) everything is flat with few shadows to give shapes????
 
<Science>
So, the reason the whole alignment of the cpl to a water reflection and then to something else method doesn't work is down the geometry of the situation being changed when you move the camera - as stated above .

Polarisation by reflection is what everyone sees when improving foliage saturation on wet days and removing reflections from water surfaces - Essentially anything that is a dielectric (not a metal or a semiconductor). Dielectric surfaces (lets assume a flat surface for the sake of ease), at any angle other than zero degrees to the surface and 90 degrees to the surface, preferentially reflect light whose electric field oscillates parallel to the surface of the reflector more than light whose electric field oscillation has a component which is perpendicular to the plane of the surface (respectively, these are known as S- and P-polarisation states). For anyone who is interested, look up Brewsters angle, 'Fresnel reflection' at a surface, and salient terms therein such as 'dipole scattering. As stated above also, a "circular polariser" in photographic vernacular is a linear polariser followed by a quarter wave plate. The latter component is what circularly polarises what ever is passed by the linear polariser. So, arriving at the point, the reason why reflections from water are reduced, is because the flat dielectric surface of water preferentially reflects light which is S polarised (Linearly polarised parallel to the plane of the surface) and the linear polariser at the front of your circular polarising filter can simply be angled to cut this out. For those that are really interested, the physical reasoning behind all this is down to the asymmetry in the environment for the very top most surface molecules.

The atmospheric effects that can be seen when using a cpl, especially in blue sky, is caused by polarisation by scattering. The reason the sky is blue is because of a process called Rayleigh scattering. This scattering effect is typical for particles much smaller than the wavelength and it just so happens that the composition of the upper atmosphere is the right constitution of matter to predominantly scatter blue light. I won't go into mega detail, but polarisation of this light is caused by dipole scattering - it dictates that if you are stood in an arbitrary position and a light source exists so as to cast light directly across you, any scattering particles in front of you will preferentially scatter light towards you that is vertically polarised, not horizontally. This is the same reason why mast antennas are stood up, not horizontal. This is also the same reason you get the dark blue area of the sky only at 90 degrees to the sun when shooting the sky with a cpl. However. And yes there is a however. The magnitude of this effect is dependent on the concentration of scatters - the number of times light is scattered before reaching the observer. This is partly the reason why clouds are largely unaffected - the other reason is to do with the particle size in clouds. Haze is typically made of water vapour on humid days, pollution and other stuff - particles much larger than in clean, dry air, and so this same polarisation by scattering does not have the same effect. As such it's not likely a CPL will do much to cut through haze. (I'm not saying it wont have any effect at all, simply that it'll be significantly reduced.
</Science>
 
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stevelmx5 said:
There should normally be a mark/dot on the front ring polariser. Basically, regardless of which way you're pointing the lens, that dot should be pointed towards the sun (with it 90 degrees to the lens). Anything other than that and you will see little/no effect.

Also, if you use it on a wide angle lens you will probably get some random effects in the sky where the polarisation doesn't apply equally across the frame.
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I wasn't aware that the white stripe does this.

I agree that using a polariser with a wide-angle lens can cause uneven polarisation, the more so the wider the lens. it's sometimes possible to hide this behind clouds, and there are also ways to remove it in PP, though. It's not that great a problem these days.
 
Woodsy said:
<Science>
So, the reason the whole alignment of the cpl to a water reflection and then to something else method doesn't work is down the geometry of the situation being changed when you move the camera - as stated above .

Polarisation by reflection is what everyone sees when improving foliage saturation on wet days and removing reflections from water surfaces - Essentially anything that is a dielectric (not a metal or a semiconductor). Dielectric surfaces (lets assume a flat surface for the sake of ease), at any angle other than zero degrees to the surface and 90 degrees to the surface, preferentially reflect light whose electric field oscillates parallel to the surface of the reflector more than light whose electric field oscillation has a component which is perpendicular to the plane of the surface (respectively, these are known as S- and P-polarisation states). For anyone who is interested, look up Brewsters angle, 'Fresnel reflection' at a surface, and salient terms therein such as 'dipole scattering. As stated above also, a "circular polariser" in photographic vernacular is a linear polariser followed by a quarter wave plate. The latter component is what circularly polarises what ever is passed by the linear polariser. So, arriving at the point, the reason why reflections from water are reduced, is because the flat dielectric surface of water preferentially reflects light which is S polarised (Linearly polarised parallel to the plane of the surface) and the linear polariser at the front of your circular polarising filter can simply be angled to cut this out. For those that are really interested, the physical reasoning behind all this is down to the asymmetry in the environment for the very top most surface molecules.

The atmospheric effects that can be seen when using a cpl, especially in blue sky, is caused by polarisation by scattering. The reason the sky is blue is because of a process called Rayleigh scattering. This scattering effect is typical for particles much smaller than the wavelength and it just so happens that the composition of the upper atmosphere is the right constitution of matter to predominantly scatter blue light. I won't go into mega detail, but polarisation of this light is caused by dipole scattering - it dictates that if you are stood in an arbitrary position and a light source exists so as to cast light directly across you, any scattering particles in front of you will preferentially scatter light towards you that is vertically polarised, not horizontally. This is the same reason why mast antennas are stood up, not horizontal. This is also the same reason you get the dark blue area of the sky only at 90 degrees to the sun when shooting the sky with a cpl. However. And yes there is a however. The magnitude of this effect is dependent on the concentration of scatters - the number of times light is scattered before reaching the observer. This is partly the reason why clouds are largely unaffected - the other reason is to do with the particle size in clouds. Haze is typically made of water vapour on humid days, pollution and other stuff - particles much larger than in clean, dry air, and so this same polarisation by scattering does not have the same effect. As such it's not likely a CPL will do much to cut through haze. (I'm not saying it wont have any effect at all, simply that it'll be significantly reduced.
</Science>
Click to expand...

Thanks mate, I'd just typed all that out on my phone but you've beaten me to it...
 
excalibur2 said:
Well for landscapes the polariser has limited use if you believe at midday in summer (sun 90 degrees to the camera) everything is flat with few shadows to give shapes????
Click to expand...

Am not quite sure what your point is? There are plenty of reasons for not doing landscapes at mid-day in mid-summer. The limited effectiveness of a polariser is just one of them!

For what it's worth, after many years of experience I've come to the conclusion that a polariser seems to give most pleasing results for landscapes 2 or 3 hours after sunrise and and the same before sunset.
 
Woodsy said:
<Science>
So, the reason the whole alignment of the cpl to a water reflection and then to something else method doesn't work is down the geometry of the situation being changed when you move the camera - as stated above .

Polarisation by reflection is what everyone sees when improving foliage saturation on wet days and removing reflections from water surfaces - Essentially anything that is a dielectric (not a metal or a semiconductor). Dielectric surfaces (lets assume a flat surface for the sake of ease), at any angle other than zero degrees to the surface and 90 degrees to the surface, preferentially reflect light whose electric field oscillates parallel to the surface of the reflector more than light whose electric field oscillation has a component which is perpendicular to the plane of the surface (respectively, these are known as S- and P-polarisation states). For anyone who is interested, look up Brewsters angle, 'Fresnel reflection' at a surface, and salient terms therein such as 'dipole scattering. As stated above also, a "circular polariser" in photographic vernacular is a linear polariser followed by a quarter wave plate. The latter component is what circularly polarises what ever is passed by the linear polariser. So, arriving at the point, the reason why reflections from water are reduced, is because the flat dielectric surface of water preferentially reflects light which is S polarised (Linearly polarised parallel to the plane of the surface) and the linear polariser at the front of your circular polarising filter can simply be angled to cut this out. For those that are really interested, the physical reasoning behind all this is down to the asymmetry in the environment for the very top most surface molecules.

The atmospheric effects that can be seen when using a cpl, especially in blue sky, is caused by polarisation by scattering. The reason the sky is blue is because of a process called Rayleigh scattering. This scattering effect is typical for particles much smaller than the wavelength and it just so happens that the composition of the upper atmosphere is the right constitution of matter to predominantly scatter blue light. I won't go into mega detail, but polarisation of this light is caused by dipole scattering - it dictates that if you are stood in an arbitrary position and a light source exists so as to cast light directly across you, any scattering particles in front of you will preferentially scatter light towards you that is vertically polarised, not horizontally. This is the same reason why mast antennas are stood up, not horizontal. This is also the same reason you get the dark blue area of the sky only at 90 degrees to the sun when shooting the sky with a cpl. However. And yes there is a however. The magnitude of this effect is dependent on the concentration of scatters - the number of times light is scattered before reaching the observer. This is partly the reason why clouds are largely unaffected - the other reason is to do with the particle size in clouds. Haze is typically made of water vapour on humid days, pollution and other stuff - particles much larger than in clean, dry air, and so this same polarisation by scattering does not have the same effect. As such it's not likely a CPL will do much to cut through haze. (I'm not saying it wont have any effect at all, simply that it'll be significantly reduced.
</Science>
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Gasp! ;)
 
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jerry12953 said:
Am not quite sure what your point is? There are plenty of reasons for not doing landscapes at mid-day in mid-summer. The limited effectiveness of a polariser is just one of them!

For what it's worth, after many years of experience I've come to the conclusion that a polariser seems to give most pleasing results for landscapes 2 or 3 hours after sunrise and and the same before sunset.
Click to expand...

Well the confusion is the polariser works best 90 degrees to the camera and doesn't work well with the sun behind you........but I'm sure everyone has seen a scene where the sun is facing you (not low) e.g. a village and the scene looks crap, yet turn around and look back and the scene looks great. So if you have time (well we are filmies) why try and cut through the haze (with the crappy scene in front of you) when you can wait till the sun moves round for a better picture.
Like you, and for my area, I know when church, villages, scenery etc look best at certain times of the day and if haze is around would hope a polariser would cut through it...as for enhancing colours surely Photoshop would do that?
 
A UV filter would be best for cutting through haze, or a mild warm up filter (81B?) to counteract the blue.
 
"Thanks for the link Richard....I have about 40.. filtek, Hunter and Cokin flat filters from a heart shape hole to grad tabac and all I have used in the past (ages ago), for colour, is a polariser and diffuser...so for a new hobby will use these other filters more."

Brian, I am truly sorry,I thought the thread was about polarizing filters. My mistake.
 
medwaygreen said:
"Thanks for the link Richard....I have about 40.. filtek, Hunter and Cokin flat filters from a heart shape hole to grad tabac and all I have used in the past (ages ago), for colour, is a polariser and diffuser...so for a new hobby will use these other filters more."

Brian, I am truly sorry,I thought the thread was about polarizing filters. My mistake.
Click to expand...

;) but sorting through my drawer of filters thought I'd try the polariser again and it sort of went on from there with the others.
 
Woodsy said:
<Science>
So, the reason the whole alignment of the cpl to a water reflection and then to something else method doesn't work is down the geometry of the situation being changed when you move the camera - as stated above .

Polarisation by reflection is what everyone sees when improving foliage saturation on wet days and removing reflections from water surfaces - Essentially anything that is a dielectric (not a metal or a semiconductor). Dielectric surfaces (lets assume a flat surface for the sake of ease), at any angle other than zero degrees to the surface and 90 degrees to the surface, preferentially reflect light whose electric field oscillates parallel to the surface of the reflector more than light whose electric field oscillation has a component which is perpendicular to the plane of the surface (respectively, these are known as S- and P-polarisation states). For anyone who is interested, look up Brewsters angle, 'Fresnel reflection' at a surface, and salient terms therein such as 'dipole scattering. As stated above also, a "circular polariser" in photographic vernacular is a linear polariser followed by a quarter wave plate. The latter component is what circularly polarises what ever is passed by the linear polariser. So, arriving at the point, the reason why reflections from water are reduced, is because the flat dielectric surface of water preferentially reflects light which is S polarised (Linearly polarised parallel to the plane of the surface) and the linear polariser at the front of your circular polarising filter can simply be angled to cut this out. For those that are really interested, the physical reasoning behind all this is down to the asymmetry in the environment for the very top most surface molecules.

The atmospheric effects that can be seen when using a cpl, especially in blue sky, is caused by polarisation by scattering. The reason the sky is blue is because of a process called Rayleigh scattering. This scattering effect is typical for particles much smaller than the wavelength and it just so happens that the composition of the upper atmosphere is the right constitution of matter to predominantly scatter blue light. I won't go into mega detail, but polarisation of this light is caused by dipole scattering - it dictates that if you are stood in an arbitrary position and a light source exists so as to cast light directly across you, any scattering particles in front of you will preferentially scatter light towards you that is vertically polarised, not horizontally. This is the same reason why mast antennas are stood up, not horizontal. This is also the same reason you get the dark blue area of the sky only at 90 degrees to the sun when shooting the sky with a cpl. However. And yes there is a however. The magnitude of this effect is dependent on the concentration of scatters - the number of times light is scattered before reaching the observer. This is partly the reason why clouds are largely unaffected - the other reason is to do with the particle size in clouds. Haze is typically made of water vapour on humid days, pollution and other stuff - particles much larger than in clean, dry air, and so this same polarisation by scattering does not have the same effect. As such it's not likely a CPL will do much to cut through haze. (I'm not saying it wont have any effect at all, simply that it'll be significantly reduced.
</Science>
Click to expand...

Wowsers, it's almost like you're a physicist or something!
 
excalibur2 said:
Well the confusion is the polariser works best 90 degrees to the camera and doesn't work well with the sun behind you........but I'm sure everyone has seen a scene where the sun is facing you (not low) e.g. a village and the scene looks crap, yet turn around and look back and the scene looks great. So if you have time (well we are filmies) why try and cut through the haze (with the crappy scene in front of you) when you can wait till the sun moves round for a better picture.
Like you, and for my area, I know when church, villages, scenery etc look best at certain times of the day and if haze is around would hope a polariser would cut through it...as for enhancing colours surely Photoshop would do that?
Click to expand...

I'd definitely agree that waiting for the sun is the best option. A polariser really doesn't cut through haze very well. Haze is a specific atmospheric condition so it may be you are using the terminology in a different way. A polariser will enhance colours in a way that I don't think software can do.

I honestly think your best bet would be to get to know how to best use a polariser. It will take a bit of trial and error but it will be worth it.
 
jerry12953 said:
I'd definitely agree that waiting for the sun is the best option. A polariser really doesn't cut through haze very well. Haze is a specific atmospheric condition so it may be you are using the terminology in a different way. A polariser will enhance colours in a way that I don't think software can do.

I honestly think your best bet would be to get to know how to best use a polariser. It will take a bit of trial and error but it will be worth it.
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Indeed.
 
*Must... resist... urge.. to... science...*

The thing is, for their intended purpose (in front of digital camera sensors and pieces of film), they are all going to perform fine. The chances are, among all the makes, there's probably only a few companies that actually make the constituent filters (this is just a guess and not based on any evidence, only past experiences in similar situations)

I know I have distorted sense of good and bad when it comes to things like this, but if the extinction ratio for the linear polariser is anything better than 100:1, I'll eat my hat*. It's what makes them cheap to make.

* I don't own a hat.
 
Woodsy said:
*Must... resist... urge.. to... science...*

The thing is, for their intended purpose (in front of digital camera sensors and pieces of film), they are all going to perform fine. The chances are, among all the makes, there's probably only a few companies that actually make the constituent filters (this is just a guess and not based on any evidence, only past experiences in similar situations)

I know I have distorted sense of good and bad when it comes to things like this, but if the extinction ratio for the linear polariser is anything better than 100:1, I'll eat my hat*. It's what makes them cheap to make.

* I don't own a hat.
Click to expand...

All your hats already eaten, then? ;)
 
This white marker on the Hoya polariser is confusing:-
With the sun directly behind me (9:30 in the morning) and removing white sky from the pond, the marker is upright (TDC), yet a patch of blue sky with the camera at about 90 degrees to the sun (9:30 in the morning) the blue sky darkens when marker is pointed roughly to the sun (not TDC) h'mm
 
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It's because the two polarisation effects are orthogonal. The white marker, I would imagine, simply defines the transmission axis of the linear polariser. If you're seeing different effects at different rotations, it's because the light coming towards you is not polarised in the same axis.
 
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Woodsy said:
It's because the two polarisation effects are orthogonal.
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:eek: erm what's that in plain English. Also to nail down this thread:- If you use a polariser just for removing reflection from glass, water etc it doesn't matter where the sun is (within reason) or even if a cloudy day..it will work. The problem is scenery where the best solution (it seems to me) is to use your eyes in the viewfinder and if you see a change ( e.g. blue sky darkening) then it's working...suck it and see....and if say the blue sky darkens then it is at optimum for removing haze.
 
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He means at right angles in plain English :)
Just use the viewfinder and see what happens.

WYSIWYG
 
I suggest ignoring the white marker. I've hardly ever used it myself, and then in exceptional circumstances. Just go outside and use the filter in real-life situations, as you have already started to do.

Yes, the effect of the filter should be clearly visible in the v/f. It's really a WYSIWYG filter!

But don't get confused about "haze". A polariser is of limited use in really hazy conditions.
 
Orthogonal means at 90 degrees. Ok, so the fundamental origin of any effect you see in the viewfinder, whether it's water reflections being reduced, blue sky darkening, etc etc, is because there is some physical process going on which, by some degree, turns unpolarised light into light which is polarised in a certain direction. It's not as perfect as this in real situations, but let's say that it is for now. The polarisation of light is the principle of knowing in which direction the electric field of the photon is oscillating. For linearly polarised light, it oscillates in a single plane / direction. Imagine looking at a clock face dead on where the clock has degrees instead of time numbers, and only one hand. The photon is coming out of the face directly towards you. The hand can sit at any angle of rotation. It is this angle which defines the direction that the field is oscillating.

Linear polarisers are sensitive to this angle of oscillation as they have what is called a transmission axis. If this axis angle is aligned with the polarisation angle of the light hitting it, the light will pass. If it's at 90 degrees to this angle, the light will be stopped / attenuated. Look up Malus's Law if you're interested. Circular polarisers in fact have a linear polariser first which acts as the first filter component in a cpl.

The light you are seeing from the reflection of water is more likely to be polarised horizontally. Therefore, if you place your polariser with the transmission axis vertically, it'll block out a lot of the reflection. Hence, the white marker on your filter probably defines the transmission axis. The light coming from blue sky when facing 90 degrees to the sun is more likely to be polarised vertically, so to see this effect, you have to rotate your polariser 90 degrees from when you tested the water scenario.

To answer your point / question "If you use a polariser just for removing reflection from glass, water etc it doesn't matter where the sun is (within reason) or even if a cloudy day..it will work. The problem is scenery where the best solution (it seems to me) is to use your eyes in the viewfinder and if you see a change ( e.g. blue sky darkening) then it's working.".

In regards to the first bit, without exercising extreme pedantry, yes. It'll work. In regards to the second bit, yes, WYSIWYG as Ken aptly put it.

I'll shut up now.
 
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Thanks Jonathon and all..and who knows I might be an expert on polarisers in 6 months time. We all know what polarisers basically do and for scenery will sus out the problem about wide angle lenses (that someone mentioned)..I've got a polariser on a 35mm flek ATM and will see if any problems say for a 24mm and as for haze I think the overall view is:- It will cut it down but don't expect too much.
As for the air around polluted cities it seems the jury is out on that one, maybe the polariser doesn't work for petrol\diesel\factories etc pollution.
 
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Wow look at those prices you could get a nice film camera plus lens for that....I wonder where my bootie polarisers for 50p would come in the ranking for results ;)
 
excalibur2 said:
Well I don't understand what you are saying...are you saying "if I set the polariser on the lens for the pond to remove reflection from the sky, then it won't work if I point the lens in another direction?"
But for the two shots...... I set the polariser for the puddle, then pointed the lens at London (which was a different direction) and took one shot but didn't remove the polariser but turned it 180 degrees so the polariser should have been off but the results were similar in cutting through the haze. I'll have to do a test away from London as it looks like it's too polluted.......h'mm no one has said "a polariser is useless cutting through pollution" anyone got proof either way?
Click to expand...
Yep, one of two reasons why they're adjustable :)
 
Well I was out yesterday and can confirm a polariser will reduce haze slightly and you can see it in the viewfinder but the problem for some filmies (me) is:- in wearing spectacles with the sun high and trying to remove extraneous light coming in the side of the viewfinder to see what a polariser does and I do have a rubber viewfinder hood....h'mm back to the old days of a cloth over my head and camera :D
AAMOI using a digi can you see the difference on the screen?
Also thinking:- my shots of the tower blocks in London were about 18 miles away so it's probably impossible to cut through 18 miles of pollution and surely even using a 500mm lens it would only compact the pollution?. But then spy satellites\planes must have some means of cutting through pollution over cities as e.g. the government asking for say shots of a crisis in a city and would the military reply "you'll have to wait for a few weeks as the weather forecast is for a clear period then ". :rolleyes:
 
Woodsy said:
<Science>
So, the reason the whole alignment of the cpl to a water reflection and then to something else method doesn't work is down the geometry of the situation being changed when you move the camera - as stated above .

Polarisation by reflection is what everyone sees when improving foliage saturation on wet days and removing reflections from water surfaces - Essentially anything that is a dielectric (not a metal or a semiconductor). Dielectric surfaces (lets assume a flat surface for the sake of ease), at any angle other than zero degrees to the surface and 90 degrees to the surface, preferentially reflect light whose electric field oscillates parallel to the surface of the reflector more than light whose electric field oscillation has a component which is perpendicular to the plane of the surface (respectively, these are known as S- and P-polarisation states). For anyone who is interested, look up Brewsters angle, 'Fresnel reflection' at a surface, and salient terms therein such as 'dipole scattering. As stated above also, a "circular polariser" in photographic vernacular is a linear polariser followed by a quarter wave plate. The latter component is what circularly polarises what ever is passed by the linear polariser. So, arriving at the point, the reason why reflections from water are reduced, is because the flat dielectric surface of water preferentially reflects light which is S polarised (Linearly polarised parallel to the plane of the surface) and the linear polariser at the front of your circular polarising filter can simply be angled to cut this out. For those that are really interested, the physical reasoning behind all this is down to the asymmetry in the environment for the very top most surface molecules.

The atmospheric effects that can be seen when using a cpl, especially in blue sky, is caused by polarisation by scattering. The reason the sky is blue is because of a process called Rayleigh scattering. This scattering effect is typical for particles much smaller than the wavelength and it just so happens that the composition of the upper atmosphere is the right constitution of matter to predominantly scatter blue light. I won't go into mega detail, but polarisation of this light is caused by dipole scattering - it dictates that if you are stood in an arbitrary position and a light source exists so as to cast light directly across you, any scattering particles in front of you will preferentially scatter light towards you that is vertically polarised, not horizontally. This is the same reason why mast antennas are stood up, not horizontal. This is also the same reason you get the dark blue area of the sky only at 90 degrees to the sun when shooting the sky with a cpl. However. And yes there is a however. The magnitude of this effect is dependent on the concentration of scatters - the number of times light is scattered before reaching the observer. This is partly the reason why clouds are largely unaffected - the other reason is to do with the particle size in clouds. Haze is typically made of water vapour on humid days, pollution and other stuff - particles much larger than in clean, dry air, and so this same polarisation by scattering does not have the same effect. As such it's not likely a CPL will do much to cut through haze. (I'm not saying it wont have any effect at all, simply that it'll be significantly reduced.
</Science>
Click to expand...
Exactly what I was going to say but you beat me to it, well done Woodsy (y)
 
excalibur2 said:
Well I was out yesterday and can confirm a polariser will reduce haze slightly and you can see it in the viewfinder but the problem for some filmies (me) is:- in wearing spectacles with the sun high and trying to remove extraneous light coming in the side of the viewfinder to see what a polariser does and I do have a rubber viewfinder hood....h'mm back to the old days of a cloth over my head and camera :D
AAMOI using a digi can you see the difference on the screen?
Also thinking:- my shots of the tower blocks in London were about 18 miles away so it's probably impossible to cut through 18 miles of pollution and surely even using a 500mm lens it would only compact the pollution?. But then spy satellites\planes must have some means of cutting through pollution over cities as e.g. the government asking for say shots of a crisis in a city and would the military reply "you'll have to wait for a few weeks as the weather forecast is for a clear period then ". :rolleyes:
Click to expand...


Haze is normally only a relatively thin layer close to the earth's surface so looking down through it (as from a spy plane/satellite) wouldn't be too bad.

On the other hand looking horizontally through 18 miles of the stuff, as you do when trying to photograph the landscape , is bound to cause problems.
 
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