X4 Dark Circular Polariser Filter

£169.00£255.00 Inc. VAT

3-stop or 6 stop, saturates skies and reduces reflections, reduces haze in landscapes, designed for colour-neutral performance, multi-resistant and nano coatings, made from Schott B270 glass, brass frame, knurled sides for grip



Breakthrough Photography X4 Dark Circular Polariser Filter 3 Stop and 6 Stop

These filters are a combination of outstanding circular polariser and neutral density filter giving a 3 stop or 6 stop  darkening.

The world’s most advanced circular polariser.

The moment you use theBreakthrough Photography X4 circular polariser filter, you know you’ve never used anything like it. Featuring Breakthrough Photography’s all-new American made CPL film and an all-new brass traction frame features best-in-class design and durability. And that’s just the beginning.


World’s most colour neutral CPL. Guaranteed.

Their all-new and internally developed CPL film is at the core of the X4 CPL, and they manufacture it in California. To achieve the worlds most colour neutral performance, Breakthrough Photography had to develop a unique approach to manufacturing rather than selecting off-the-shelf CPL film common among filter manufacturers, which is designed and intended for LCD panels, not photographic optics.

All commercially available CPL filters exhibit a yellow cast due to a gradual transmission increase starting around 600nm and then spiking at 650nm onward into IR. With Breakthrough Photography’s X4 CPL film they achieved a gradual transmission decrease from 600nm onward, and instead of spiking uncontrollably near 650nm and far into infrared, the X4 CPL sees very controlled transmission into IR, without the curve spike. The real world result? Warm and lively images without the apparent colour cast.

Transmission Curve

Spectrometers are optical instruments that can detect spectral lines and measure their wavelength or intensity. Spectrometers can also be used to test the efficiency of an optical filter in order to evaluate colour neutral performance.

A perfectly flat transmission curve would yield a perfectly colour neutral result, and while there is no such thing as a perfectly neutral CPL filter (contrary to what other filter makers may claim) the X4 CPL is the most colour neutral any CPL filter, guaranteed.

When filter makers use off-the-shelf polarising films originally designed for LCD panels, it produces a predictable transmission increase at 650nm onward and a spike in transmission around around 680nm and into IR. During their research into alternative manufacturing methods, they were able to solve this problem. As a result the X4 CPL sees a decline in IR transmission across the visible spectrum and is very well controlled throughout the IR range.

Expand your dynamic range in-camera.

Outdoor photographers frequently struggle with dynamic range, as the human eye has a dynamic range over 20-stops, while a mid-day outdoor scene (like the one below) may range between 15-18 stops. Professional camera systems range between 12-14 stops, and during the last decade very little expansion progress has been made. You can sometimes recover detail in shadows if there’s enough data there in post-processing, but you can’t remove glare in post-processing, and the removal of glare adds vibrancy, contrast and reveals details that are otherwise unseen.

When you rotate a circular polariser you will see it turn ON and OFF through the viewfinder, allowing you to control the amount of polarisation necessary for your shooting situation. The higher in elevation you shoot, the more pronounced the polarisation, and the more dynamic range is increased as a result

No Filter vs. X4 CPL

A winning design proven by outdoor photographers.

Breakthrough Photography took all they learned from the success of the X4 ND and designed an entirely new circular polarizing frame, unlike you’ve ever seen before. And like the X4 ND, they specifically designed the X4 CPL as a workhorse CPL for field work, built to withstand extreme wind, salt water, dust and other abrasive conditions and elements where other filters may fail. And they guarantee each and every X4 CPL to perform with optimal optical clarity and colour neutrality for 25 years even in the harshest of conditions,

World’s sharpest CPL filter. Guaranteed.

The X4 CPL features SCHOTT Superwhite B270® optical glass, which is an ultra clear crown glass. It is produced by melting high purity raw materials and then made using the continuous draw process. The result is excellent transmission in the ultraviolet, visible, and infrared spectrums, and a high surface quality that accepts our state-of-the-art MRC and nanotec® coatings exceptionally well.

Their state-of-the-art multi-resistant coating (MRC) is an optical coating applied to both surfaces of the glass disk to reduce reflection and to increase surface durability. Their proprietary MRC coating is structurally harder than the glass itself and the reduced reflections improve the efficiency since less light is lost. The reduction of reflections also improves the contrast of the image by elimination of stray light. The real world result? Better contrast and colour.

Low light transmission and green flaring are common problems with uncoated glass. As MRC coatings are added to each side of the optical disk light transmission steadily increases with flaring steadily decreasing. In our lab tests light transmission apexes at about 16-layers of MRC, and slowly decreasing in transmission at 18 and above. 8-layers of MRC are applied evenly to both sides of each optical disk resulting in MRC16.


Breakthrough Photography X4 Circular Polariser Filter Reviews

Review – David Clapp – Renowned landscape photographer

Review – The Digital Photography School

Review – The Phobographer

Review – Points In Focus

Additional information

Thread Size

46mm, 49mm, 52mm, 58mm, 62mm, 67mm, 72mm, 77mm, 82mm, 95mm, 105mm, Magnetic


3 Stop, 6 Stop

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Tel: 01798 306599