7-14 Polariser Details

Although the 7-14 Adapter is designed for the Nisi V5 Pro filter holder, which ships with a C-PL, the C-PL cannot be used. The 7-14 Adapter replaces the Nisi V5 Pro Adapter including the C-PL. Whilst it would have been possible to accomodate it, large amounts of vignetting would occur. Currently there are no circular C-PL's large enough to suit the Olympus 7-14's huge field-of view. A circular C-PL would need to be around 150mm diameter, therefore making the use of 100mm filters redundant.

There is a work-around for using a polariser with this lens. Care is needed when using polarisers on ultra wide lenses. Please see the details below for important information.
Llandwyn Image
Olympus 7-14mm f2.8 with Polariser

Limitations of use for polarisers on ultra wide lenses is not because of quality of filter or lens, it is just the nature or physics of light.

Light from the sun is not polarized and can be affected by many things, haze, angle of view from the sun, diffraction, and reflective surfaces. As light passes through the atmosphere blue wavelengths are affected, which is why the sky can appear a paler blue in different angles and different seasons.

For Photographers, what is important to know is that only a narrow band of a scene, around 85º, will have the best effect from a polarizer, around 12mm or 24mm Full Frame, and at around 90º to the sun. Ultra wide angle lenses will capture more of a scene and therefore can have strange effects.

The image above demonstrates this. Taken on Llandwyn Island Anglesey using the 7-14 f2.8, the sun was not at 90º to the scene, and the lens took in a huge 110º view. The effect is a pronounced dark blue circle in the sky. The image would have been more successful using a 12mm lens and polariser, or no polariser. The same effect will also occur on a large flat body of water such as a lake, where part of the image will have reflections removed and part will not.
Light Graphic
The optimum angle for effective polarization is 90º to the sun.
A field of view of around 85º will reduce the parts of a scene that cannot be polarized. Using ultra wide lenses such as the Olympus 7-14 has a much wider field of view and will include parts of a scene where a polarizer is ineffective.

When Is a Useful Situation to Use a Polariser?
A polariser on such a wide lens is not to be left on all the time as with other narrower lenses, however it can be used effectively with consideration and thought.

The images below were all taken with the 7-14 using a square Nisi HD polarizer. The main aim was to saturate colour and remove reflections from wet rocks and foliage.
Square polariser graphic
A work-around to using a C-PL is a square 100x100mm slot in C-PL. The Nisi HD Polariser can be used without the need to rotate which would be difficult if used with graduated filters. Inserted upright it will give full polarization, rotate 90º will give around half polarization. Turned upside down will produce no polarization, useful to use as a 1.5 stop ND. This will provide an effective solution for polarization, providing the limitations of using ultra wide lenses is considered and care is taken.
sample image 1
Olympus OMD EM1mk2 7-14mm @7mm, Nisi HD Polariser, Nisi Medium Graduated Filter

Llyn Idwal, Snowdonia
No ND filter used, ambient light low enough for around 1s exposure. Note the reduced sky and reduced issue of colour banding shooting portrait orientation. In the second image note the amount of textured cloud which would conceal any issues. The polariser served to reduce shutter speed and remove reflections from wet rocks and foliage, allowing for increased saturation.
sample image 2
Olympus EM1mk2, 7-14mm @ 7mm, Nisi HD Polariser, Nisi 2 Stop Medium Grad

Mary's Shell, Clevelys
HD Polariser rotated 90º to maintain water reflections whilst giving just enough to cut through reflections on the structure.
sample image 3
Olympus EM1mk2, 7-14mm @8mm, Nisi HD Polariser, Nisi 2 Stop Medium Grad

Keswick, Lake District
3 image panoramic stitch taken hand held with exposure lock. Note the pale blue sky right, although with the amount of cloud detail it is acceptable.
sample image 4
When A Polariser Should Not Be Used
Olympus EM1mk2 7-14mm @7mm, Nisi IRGND 10 stop, 2 stop Medium Grad

Lone Tree, Llanberris, Snowdonia
Although useful, polarisers are one of the most overused filters. This imaged relies on the reflections on the calm water which a polarisers would have reduced or removed. There are good uses for polarisers, but think before you use one.