STC Star Mist Clip Filter

In this, the third of the current series of STC filter reviews we are looking at the STC Star Mist Clip Filter.

As always, my thanks go to STC Taiwan for the generous provision of the Star Mist Clip Filter

What is a Star Mist filter? It is a filter designed to enhance highlights and increase halo effect without excessively impacting sharpness and contrast of the overall image, one of the reasons behind making the filter was that digital cameras can record an image of a night sky with stars appearing as pinsharp dot of light, the STC Star Mist filter creates a subtle glow around each star creating a more pleasing photograph, a second use of the filter is to create portraits with a soft glow in the highlights, whilst slightly reducing the contrast between highlight and shadow detail.

A little about the filter itself – like all STC filters, the STC Star Mist Clip Filter is supplied in a hard plastic case along with a STC branded anti-static cleaning cloth and a signed certificate proving the filter has been tested and passed all quality checks, this particular filter also come with a magnetic removal tool for those who feel uncomfortable putting their fingers inside their camera. The frame is made from aerospace grade aluminum alloy with an adonised black finish and the glass filter is double-sided hydrophobic, anti-smudge and antistatic coated, additionally the frame utilises a patented glass assembly to ensure the filter remains flat at all times irrespective of temperature fluctuations. In regards to the filter itself, to quote STC, they have ‘developed a filter that incorporates “sub-micron transparent microcrystals” used in liquid crystal processes to create a specialized mist effect.’ This particular filter is produced in two strengths, 1 being the weaker and 2 with a stronger level of glow and diffusion.

STC clip filters are unique in that they are inserted into the camera rather than fitted to the from of the camera lens, worth mentioning is that there are 2 variants of clip filter made for Sony full frame camera bodies – they are not interchangeable, make sure you purchase the correct one. As with all their clip filters STC state on their website that force should not be used when inserting the filter and if there is a problem to contact STC direct.

Test Procedure

The camera used for all the tests was equipped with a 35mm f2 lens and mounted on a Manfrotto 190 tripod with a ball and socket head, exposures were made in aperture priority, daylight balance, with ISO set at 200 and recorded as a RAW file. Images were viewed on a colour callibrated monitor. Photographs were taken late evening to take advantage of the low light levels. A series of exposures were made from ‘as’ metered to 3 stops underexposed to test the effect of exposure on the glow effect, both with filter and without.

Results

With filter                                                                                                                             Without filter

 

       Underexposed with filter                                                                                            Underexposed without filter

 

                                                 Exposure adjusted with filter                                                                                            Exposure adjusted without filter

 

       Glow effect at varying exposures with filter                                                               Glow effect at varying exposures without filter

 

Sample Photographs

Conclusions

Having tested the STC Star Mist filter at varying apertures with shutter speed adjusted accordingly, I noted that aperture size does not affect the amount of glow produced – whereas over and under exposure does make a difference. Although this becomes less obvious if the image is subsequently adjusted for density in post processing. It has been noticed however that sometimes by overexposing by a third to half a stop with the filter in place a pleasing glow can be created in the highlights, yet without the filter the image just looks overexposed with blown out highlights.

In my opinion, when a photograph taken with the STC Star Mist filter is processed as a black and white image the result looks as though it could have been taken on a film camera rather than a digital one.

A point worth mentioning is that as with all clip filters infinity focus changes, so if using a manual focus lens, do not set focus by the lens scale but focus through the eyepiece or on screen.

All STC filters are made using state of the art high grade materials and finished to a very high standard and this clip filter is no exception.

Do I recommend buying a STC Star Mist clip filter? If you want to give your night photographs and or portraits (did I forget to mention those?) an extra lift, then this is the filter for you. Mine now has a permanant place in my camera bag.

The STC Star Mist clip filter for a Sony A7 R IV costs in the region of $90/£90 and can be obtained either from STC Taiwan direct or from your local stockist.