In this episode, I am at the House of Bruar’s waterfalls in Scotland and will use the Polarising Filter and a 10 Stop ND filter to capture the movement in the water.
All photographs below were taken at ISO400, f18-f16, 30sec:



What is a Polarising filter?

Sky
Since it removes the light reflection on water surfaces, it provides us with darker and more saturated skies as the light reflection on the water droplet contained in the atmosphere is removed.
Water
When used for capturing water scenery, i.e. lochs, it gives a more transparent look to it so we can see the bottom (providing there is not much movement on the water). Depending on the angle of the light and the filter itself the effect will vary.
Tree leaves
I love using it when shooting landscapes with colourful trees, especially after rain. The water on the leaves usually shines much, and the colours are not so explicit. With a Polarising filter, you give a whole new saturated life back to the colours.
Up to 2 stops
Good Polarising filters will decrease the amount of light that is received by the sensor/film by up to 2 stops. While in this episode this certainly played to our advantage, when shooting is low light environment (dusk or dawn) it will require us to reduce the shutter speed adequately.
Circular or Linear
When talking about circular or linear, one does not refer to the shape of the filter, i.e. being round or square, as a matter of a fact it is down to the way the polarisation works. I do not know the technical differences but from a photography perspective, most if not all modern DSLR’s requires the Circular type and old SLR’s would use the Linear one. It has something to do with whether a camera has a spot metering and an auto-focus system.
Square or Circle?
Polarising filters like any other filter come in either square/rectangle or circular shapes. They are both identical regarding performance and quality. The difference lies with whether you own multiple lenses with different diameters which would mean you would need to buy several circle filters (ends up being expensive, i.e., £70/filter) to accommodate your lenses or choose a square/rectangle type that fits on a filter holder which then only requires different attachment rings (very cheap i.e. £5).
When to use a Polarising Filter?
Polarising filters can be used any time in the day. The only real rule is the shot needs to be taken at 90 degrees from the sun. Such filter is a must when shooting in humid condition to reveal the great colours. Avoid using such filter when shooting through a window or transparent plastic/perspex as those might interfere with the polarisation and weird colour shades can appear. Wide angle lenses (<28mm Full frame equivalent) can produce uneven results.
What is the Black Glass?

Such filter absorbs light almost like a black hole, and to use it, one needs to either focus before fitting the filter on the camera or rely on the Live View mode (LCD) of the camera to be able to focus through the filter.
This filter opens the door to amazing creations, and I will be using it in a future episode to show you some examples.