Mention B+W and if the person listening didn't hear properly he may mistake you for talking about cars. In the context of photography though, everyone knows this brand is synonymous for their quality glass filters. What kind of filters you ask - UV (Ultra-Violet), Circular Polariser and Neutral Density filters.
Most are familiar with UV filters as these are purchased not so much to reduce UV, more to protect the lens investment. The others are used as light modifiers to control or change the way and amount of light captured by the camera sensor. The favourite filter amongst landscape photographers is the Neutral Density (ND) filter. It is actually necessity for modifying the light especially in situation where the composition has a wide degree of brightness between areas of the scene. The standard ND filter has a constant darkness across the filter. A related filter is the GND (Graduated Neutral Density) and it is available in a 'Soft' or 'Hard' edge. The GND has a decreasing darkness across the filter. This makes the GND good for photographing scenes different brightness like that of the sun rising against the horizon and the dark foreground. In instances of irregular foreground objects most users like to use the 'Soft' graduated ND filter. That's a whole other debate so let's move on.
By decreasing the amount of light entering the lens, the length of time that the shutter has to be open is increased (longer time in tenths or even whole seconds). A side effect of longer exposure times leads to special effects. The effect creates a motion like blur for the scene on objects that are in motion. A good example of this is the movement of water like that of a waterfall or even that of the sea. When captured in a long exposure the water looks creamy white or whatever the base primary colour of the water is unless there's a lot of white foam/bubbles.
In bright sunlight it is impossible to capture with a slow enough shutterspeed to create this effect. Because if you did reduce your shutter speed in the bright condition your image would be over-exposed. The solution is to introduce a light modifying filter, the ND filter, to reduce the amount of light. The ND filter comes in a variety of levels rated in 'Stops'. The 10-Stop is the favourite for increasing exposure time but you can also get 3-Stop, 6-Stop, xx-Stops and you could combine them together to create a stop level to suit your needs.
Super bright Sun dictated I should shoot with 1/2000 or faster
but with ND filter I can use slower speed
Let's take a look at the leading screw type 10-Stop ND filter, the B+W 110E, and compare it against the lesser known brand NiSi.
NiSi 10-Stop ND Filter
Knobby edge for better grip
The NiSi is made in Japan and I was surprised by just how thin and light it is. It is like a 'Slim' filter and still retains a front thread so you can stack filters. A nice feature is the knobby edges around the edge of the filter which aids in tightening and loosening the filter.
B+W 10-Stop ND Filter
The B+W feels solid and that is because it is made from brass and brass as Schneider Optische Weke GmbH likes to remind people is best because it is not as susceptible to contraction in extreme cold or expansion in extreme heat. It also holds up better to repeated mounting. Both the NiSi and B+W use a screw-in lens retaining ring and not a spring clip.
The NiSi is shorter than the B+W
The camera setup is a Sony NEX-7 with the kit lens (18-55mm) and shot at the widest focal length of 18mm (27mm is the 35mm equivalent). The filters tested are of the 77mm diameter but were fitted to to the 49mm filter ring lens using step-up rings. This reduces the chances of vignetting.
The camera was Custom White Balanced using the X-Rite Color Checker Passport White Balance target as a custom white balance in the Sony NEX-7. I shot the 24 patch classic color reference target there after.
Shot taken after Custom White Balance
The B+W was fitted and as the filter is 10-stops i decreased the shutter speed by 10-stops to achieve a similar exposure to the first exposure. Note, no additional UV filter is placed on the lens. I also took a shot with the colour checker 24 patch reference in the photo. When the exposure was done I switched the filter to the NiSi 10-Stop and proceeded to take a picture of the scene. I repeated taking a shot with the 24 patch reference with filter attached.
Left B+W, Right NiSi - Uncorrected White Balance
To colour correct the filtered exposure I used LightRoom 3 and the eyedropper was placed on the lower right white patch on the X-Rite. The original WB colour temperature with the B+W filter was 5850 and +5 Tint. After using the eyedropper the White Balance Colour Temperature changed to 4200 and Tint to +6.
B+W Colour Cast, Left and Corrected WB, Right.
For the NiSi the starting colour temperature is the same from the Custom WB so that didn't change, whilst the filtered temperature did. The NiSi WB corrected Colour Temperature is 11000 and Tint +46.
NiSi Colour Cast, Left and Correct WB, Right
You can see it is easy to fix the colour cast in both instances provided you have a good reference point to indicate what is the neutral white colour. Of course in varying degrees of cool-ness or warm-ness you can adjust to your personal preference. The X-Rite Color Checker Passport makes this easy with additional colour patches with varying degrees of temperatures for cooler or warmer WB.
White Balance Colour Temperature Corrected
- It pays to have a good reference point when it comes to correcting colour casts inherent with high stop ND filters.
- Each filter type/manufacturer will vary in their colour cast as seen in the comparison review.
- You can purchase other brands and achieve similar results but only after Post Processing the RAW file.
- If you have a need to push out JPEGS in their best already corrected form you'll need to ensure you've done proper Custom White Balancing before shooting.
- The cast colour for a specific brand filter you purchase may influence your brand decision depending on your preference of warm or cool tones.
*Note: Where/when possible I tried to ensure the exposure for both the B+W and NiSi were in the same light by taking a light meter reading with a Sekonic L-358.
The B+W and NiSi filters are available from RedDotPhoto.
Pricing for the NiSi 10-Stop ND Filter To Be Advised
B+W 10-Stop S$138.00
By Chester Chen