STC Pure Hybrid CPL Filter

STC recently announced the release of a revision of their well known Hybrid CPL (Circular Polarising) Filter.

What is the difference between the ‘New’ Pure CPL Hybrid filter and its predecessor? According to STC the new filter has a more neutral colour balance.

I have used the original STC Hybrid CPL filter for some years now, so was interested to see the difference between the two filters for myself. As a result I obtained a STC Pure Hybrid CPL filter and put it to the test.

What makes the STC Pure Hybrid CPL filter special?

Made with Schott B270 super tough glass, has a double sided anti reflection, antistatic, oil and waterproof coating, the filter edge is black rimmed to reduce reflection from the edges of the filter, the filter rings are Teflon coated to ensure smooth rotation in addition to this a special polarising film is used . All in all this makes for an ultra light and ultra slim polarising filter which also cuts UV light.

Being a Hybrid filter it cuts light transmission by only 1/2 a stop whilst giving a 70% polarising effect.

The filter is supplied in a square hard plastic padded case, also included are a high quality lens cleaning cloth, a UV test card (to prove how much UV light the filter blocks) and a certificate of accreditation– STC filters are individually numbered, this identifies the filter when registering to activate the guarantee.

How the filter was tested.

For comparison purposes both the STC Hybrid CPL and STC Pure Hybrid CPL were fitted to a Nikkor 24-85mm f4.5 – f5.6 AFG lens on a Nikon D800 camera body. The combination was mounted on a tripod, using a remote shutter release. Exposures were made in Aperture Priority, using an aperture of f11, metering was set to Matrix, 100 ISO, Neutral saturation and Daylight balance, files were saved as NEF and converted to Jpeg for website use in Adobe Camera Raw without adjustment.

The NEF files were examined at 100% in Photoshop on a colour calibrated monitor.

Making the test images

Exposures were made without filter and at full polarisation. The filter ring was rotated several times on both filters to ensure that the full polarisation effect was used..The Teflon coated filter rings made rotation smooth with just the right amount of resistance.

When using full polarisation underexposing by 1/2 a stop sometimes helps compensate for the darker blue sky causing the camera to overexpose.

All photographs were taken in full sun from between 11.00 and 4.00

Test Images

Colour saturation

Without filter Original Hybrid CPL filter Pure Hybrid CPL filter

Notice the difference in the RGB channels in the example screen shots below

Without filter

Original Hybrid CPL filter

Pure Hybrid CPL filter

Without filter Original Hybrid CPL filter Pure Hybrid CPL filter

Polarisation

Without filter Original Hybrid CPL filter Pure Hybrid CPL filter

Without polarisation Polarised with Pure Hybrid CPL Filter

Without polarisation Polarised with Pure Hybrid CPL Filter

Colour difference between filters

Left – Original Hybrid CPL filter colour balance Right – Pure Hybrid CPL filter colour balance

Results

As can be seen by the above screen shots the colour rendition between ‘Without filter and Pure Hybrid CPL filter’ are quite evenly matched and more neutral, whereas the original Hybrid CPL filter shows a slight cyan cast. Sharpness with or without either of the two Hybrid CPL filters is unaffected, nor is there any evidence of fringing thanks to the ultra slim high quality Schott glass and multi coating used. The Pure filter also makes a very good job of blocking UV light – see the examples below for further proof.

STC Ultra layer UV filter STC Pure Hybrid CPL filter

Conclusions

When viewed on screen photographs taken using the Pure Hybrid CPL filter are clearly neutral, combined with only a 1/2 a stop light loss, excellent polarisation properties and being ultra slim profile and light in weight, add to this the fact that the filter is excellent at blocking UV light – this new version of Hybrid CPL filter ticks all the boxes.

I keep a STC Hybrid CPL filter on my camera lens most of the time, the minimal light loss is hardly worth bothering about, plus it has the advantage that I have instant access to a polarising filter should the need arise.

This filter is a premium product so expect to pay around £138 for a 77mm Pure Hybrid CPL filter.

Would I recommend the Pure Hybrid CPL Filter?

Short answer -Yes! The STC Pure Hybrid CPL filter will be my main filter from now on.

Extra Sample Images

STC Pure Hybrid CPL filter

Combination of STC Pure Hybrid CPL filter and STC ND 1000 clip filter

Thanks go to STC and their UK distributor InfinityX for supplying the new Pure Hybrid CPL filter for the purposes of this review.

As an extra incentive to purchase a Pure Hybrid CPL filter (or any other STC filter) there is a special 10% discount to be had when you add the discount code: 2023tpfp10off at the checkout through the link below.

https://www.stcoptics.com/discount/2023tpfp10off