STC Infra Red Clip Filters

Firstly I must thank our friends William and Ashley at STC Optics for kindly supplying the filters used in this review and to Protech Repairs for converting the Fuji X-E1 to a full spectrum pass filter.

In this review we are testing 4 STC clip filters – 3 Infra Red pass filters consisting of: 590nm, 720nm and 850nm plus a 650nm UV/IR cut filter. The Infra Red pass filters are self explanatory, they pass infra red light at varying wave lengths – the higher the number the less visible light is allowed through. What is a UV/IR cut filter? It cuts out both UV light and Infra red wavelengths – in the case of the STC clip filter, it absorbs UV and IR light and when fitted to a full spectrum pass converted camera it effectively becomes a regular camera suitable for general photography once more.

 

Let us start with a brief description of how the filters are used with a Fuji mirrorless camera.

With infra red filters (of any kind) the camera must be converted for use with infra red filters – this usually take the form of having the hot filter (this blocks infra red light) removed and replaced with a full spectrum glass. The frame of the STC clip filter is black anodised 304 stainless steel which is virtually non magnetic, the glass itself is a mere 0.5mm thick and has a special nano coating to prevent dust from sticking to it.

Installing the filter

On the reverse side of the filter the two outer edges have a sticky layer, this is revealed by removing the clear cover layer. Next remove the camera lens and place the filter into the throat of the camera, ensuring the lettering on the filter is facing outwards and the correct way up. Very gently press the outer edges of the filter to ensure the sticky layer make contact, replace the lens. Now come the important part, a custom white balance must now be made. Typically for 590nm a balance is created using a white sheet of paper, for 720nm and upwards the white balance is done using green foliage as the neutral point.

 

 

 

 

 

 

 

Inserting filter

 

 

 

 

 

 

 

 

Filter in situ.

 

The setup

For this review we used the afore mentioned full spectrum converted Fuji X-E1 plus an unconverted Fuji X-T1 as a bench mark for daylight colour balance. Two lenses were used – the lake images were taken using a Andoer 25mm f1.8 manual focus lens and for the church images a Sigma 15 – 30mm lens set to 15mm, plus a Nikon to Fuji X adapter. Custom white balances made and used as required, lenses were stopped down to f16, shutter speed set to Auto and sensitivity was 200 ISO. In all instances the camera used was fitted to a tripod. All images were saved as Jpeg fine, large and 3:2 ratio. Focus confirmed prior to exposure. Lighting conditions were bright and sunny.

The Results

 

Lake images

We have included screenshots to give additional information on how each filter behaves.

 

 

 

 

 

 

 

 

 

590mn clip filter

 

 

 

 

 

 

 

 

 

720nm clip filter

 

 

 

 

 

 

 

 

 

850nm clip filter

 

 

 

 

 

 

 

 

 

 

Full spectrum converted camera using in camera daylight setting.

 

 

 

 

 

 

 

 

 

 

Full spectrum converted camera using in camera daylight setting plus UV/IR blocking clip filter.

 

 

 

 

 

 

 

 

 

Unconverted camera using in camera daylight setting

As you can see the the amount of both overall visible colour and colour at the highlight end are suppressed as the infra red filter increases in wavelength. Also worth noting is that the UV/IR cut filter gives a slightly warmer image when compared with a conventional camera setup.

Church images

 

 

 

 

 

 

 

 

590nm clip filter

 

 

 

 

 

 

 

 

720nm clip filter

 

 

 

 

 

 

 

 

850nm clip filter

 

 

 

 

 

 

 

 

Full spectrum converted camera using in camera daylight setting.

 

 

 

 

 

 

 

 

Full spectrum converted camera using in camera daylight setting plus UV/IR blocking clip filter.

 

 

 

 

 

 

 

Unconverted camera using in camera daylight setting.

These images were taken using a Nikon fit Sigma 15-30mm lens combined with a Nikon to Fuji adapter. A fresh white balance was made before each photograph was taken. Note the slight hotspot on the infra red images, this is purely down to the choice of lens, although it is worth noting that some genuine Fuji lenses also hotspot quite badly when stopped down. We are looking to test the STC infra red clip filters with other lenses in the near future.

Conclusions

All the photographs were opened and examined at 100% in Adobe CC on a colour profiled monitor, no alterations were made, the images are just as they came from the camera. The images were observed to be sharp from edge to edge and free from distortion and fringing.

The all important question is. Do the STC clip filters offer value for money? For a Fuji X series APS-C setup prices range from $95 for a single STC clip filter infra red filter to $380 for the complete set (including case).

Whilst this might appear expensive at first glance. Consider, if you had to purchase a filter for each lens you wished to use and in some instances with ultra wide angle lenses there is no facility to fit a filter to the front of the lens in any case, the price could soon equal if not be more than the STC clip filters.

Our resounding answer would be that the STC clip filter range offer excellent quality and great value for money. Mark and I both own a number of STC clip and screw-in filters, we would not be without them.

STC are unique in the range of clip filters that they offer, fitting cameras from Nikon full frame to Pentax APS-C and most cameras in between.

 

Filters can be purchased direct from STC Optics

For further information on Infra Red conversions contact Protech Repairs

by C

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