Polarised glass - flat, underwater cameras for the use of

[sarabande]

It's all go on the Hydro today.


The angle of the sun at its hibernal solstice is causing problems for a couple of the underwater cameras.

A quick experiment with an old pair of sunglasses and a waterproof smartphone shows that some polarised glass will greatly improve the ability of the system to count fish bu making them more visible to the cameras. I can't think why we have not thought of this before

Does any one know of a source of flat polarised glass, preferably clear, and what angle of the polarisation is likely to be most effective, please ?

 

[Giblets]

Doesn't polarised glass rely on the angle of the light source (the sun) to reduce reflection? If so then surely you would need to have some arrangement to move the glass in relation to the light source to ensure a clear picture at all times.

 

[wombat88]

Polarizing/Polarized/Polarizer Filter/Film/Sheet Acetate Photography (1lee.d) UK | eBay

 

[pvb]

You can buy flat polarising filters for cameras for just a few quid. Maybe try one of those?

eg Amazon.co.uk: polarising filter

 

[johnalison]

A polarising filter is traditional for use when light will be reflected off a water surface but I have not thought about their use for an underwater camera. I presume the OP means that the camera will be underwater itself rather than just looking into the water. If water is polarised by reflection from water, my little bear's brain tells me that the light entering the water must also be polarised, being the incident light minus a polarised fraction. I can imagine that a fish viewed through a polarising filter would indeed look different since it is being lit by polarised light. In addition, the fish's scales might themselves have a polarising effect, adding or subtracting to any filter's effect. In any case, the angle of polarising will be variable and a rotating filter would be necessary for optimum use.

Can sharks detect polarised light?

 

[eilerts]

A polarising filter is traditional for use when light will be reflected off a water surface but I have not thought about their use for an underwater camera. I presume the OP means that the camera will be underwater itself rather than just looking into the water. If water is polarised by reflection from water, my little bear's brain tells me that the light entering the water must also be polarised, being the incident light minus a polarised fraction. I can imagine that a fish viewed through a polarising filter would indeed look different since it is being lit by polarised light. In addition, the fish's scales might themselves have a polarising effect, adding or subtracting to any filter's effect. In any case, the angle of polarising will be variable and a rotating filter would be necessary for optimum use.

Can sharks detect polarised light?

Stop! This is too much! I 'm supposed to contemplate over christmas gifts to people without boat, but everything else, ... but now you got me thinking about what fish see, and how do they actually navigate under water. Do they use light polarization? Damn..

 

[Fr J Hackett]

If your camera is in a housing is there room to fit a conventional photographic polarising filter on the lens? Anyway a PM to Pd is the obvious answer that is if he has relented and is now accepting communication if not a post in the lounge suitably titled should get his attention.