This review is a follow up to a previous article where we compared several brands of polarising filter.
When we last performed the test we used a STC hybrid polarising filter and a STC ND 16 (CPL-M ND16) polarising filter, one reducing half a stop of light whilst the other reducing light transmission by 4 stops of light.
We have now obtained the third filter in the set, the SHV CPL, this reduces transmission by 2 stops of light.
Transmission chart ©STC
STC screw in filters are supplied in a tough plastic case with foam inside, also supplied is a small microfibre cleaning cloth.
All three filters are made with German supplied Schott glass, ultra thin, ultra slim, cut UV light and are antistatic, oil and water resistant.
Filter line up from L to R – Hybrid CPL. SHV CPL. CPL-M ND16
For our test we used a Nikon D800, tripod mounted and equipped with a 35mm f2 lens set to f11 and used in aperture priority, white balance set to daylight and ISO 100. The shutter was triggered by wireless remote.
Once again our main test target was Eastbourne Pier, this is an ideal subject due to the struts giving a good indication of sharpness and fringing.
Testing
In the pier and sky test each filter was rotated to produce maximum increase in blue sky.
Without filter
Hybrid CPL
SHV CPL
CPL-M ND16
With the breakwater and water test, each filter was rotated to maximum reflection reduction.
Without filter
Hybrid CPL
SHV CPL
CPL-M ND16
Results
As we have come to expect from STC rotation of the filter ring is very smooth and all the filters produced sharp even edge to edge images, with a neutral colour balance.
The hybrid polarising filter gave a good level of sky saturation, both the SHV and the CPL-M ND16 increased the blue level even more, the ND16 version did however also give a slightly darker and fractionally yellow overall image, but this can easily be compensated for either in camera or at the post production stage.
The reflection test again had the hybrid filter giving a slightly less reduction in reflection compared with the SHV and the CPL-M ND16 filters as was expected.
Conclusion
All three polarising filter gave excellent results. Which one to buy? Hard to give a definitive answer. The hybrid filter is great if you want to fit a polarising filter for use under all lighting conditions due to light transmission only being reduced by half a stop. Both the SHV and the CPL-M ND16 work very well in bright light, with the ND16 version coming into its own if you like to shoot images with a wide aperture under very bright light, or wish to use slower shutter speeds, to create blur for instance.
So which one?
You could always do what we have done. Just get all three!
You can purchase STC filters direct from their eShop:https://shop.stcoptics.com/