GND is short for Graduated Neutral Density filter, which is a rectangular filter which increases the dynamic range of your camera.

Shooting a sunset with a GND filter transforms a photograph from having blown out highlights to one with incredible dynamic range, and it does this in-camera, without the need for Photoshop, stacking multiple frames or HDR.

Outdoor photographers frequently struggle with dynamic range, as the human eye has a dynamic range over 20-stops, while a mid-day outdoor scene (like the one below) may range between 15-18 stops.

Professional camera systems range between 12-14 stops, and during the last decade very little expansion progress has been made to increase dynamic range closer to what the human eye sees.

Dynamic Range

Expand your dynamic range in-camera.

If a sunset scene has a total of 17-stops between the sky and the foreground and the camera has 13-stops of in-camera dynamic range, a 2-stop soft GND and 3-stop hard reverse GND would cover that exposure gap (12 + 2 + 3 = 17) range is usually 15+ stops, which is currently too far beyond the capability of modern sensors.

Another way to think about it is that a GND filter expands in-camera dynamic range by decreasing highlight zones, similar to how the Zone System by Ansel Adams works in the darkroom.

A post-processing technique such as HDR could be used to give the impression of expanded dynamic range, but you can lose the long exposure component that is often times so central in the best sunset scenes.

Legendary landscape photographer Galen Rowell developed the GND filter with Bob Singh of Singh-Ray filters, and together they pioneered a method for covering the dynamic range gap of 35mm film.

(Singh-Ray® is an American filter manufacturing company)

A New Generation of GND.

Singh-Ray's line of American-made GND filters have been the industry leader for decades, delivering unparalleled color neutrality. Singh-Ray's use of high quality CR-39 optical resin also provided unparalleled resolving power.

The X4 GND is the world's first GND to use tempered glass, the result is the most durable GND on the market. By using SCHOTT B270 optical glass, the X4 GND resolves critically sharp. 

Incredible Durability.

Another benefit is that the optical surface does not degrade over time or with exposure with corrosive elements such as salt water and sand, common conditions for outdoor photographers.

The X4 GNDs impressive structural hardness also prevents warping, a common issue that develops over time with traditional resin filters, especially when not stored flat. Slightly warped GNDs can add slight distortion noticeable on wide-angle full-frame setup.

State-of-the-art Coatings.

Traditional CR-39 resin had exceptional sharpness performance if the surface was in mint condition, however CR-39 proved to be a poor material for accepting coatings, and therefore the industry leading CR-39 GNDs by Singh-Ray and Lee are without MRC or nano coatings.

Each X4 GND has our state-of-the-art MRC16 and nanotec coatings technology applied to both sides of the optical surface. This reduces surface reflection and nano coatings make handling and cleaning the surface of the glass easy. The nanotec coatings also let the X4 GND glide smoothly in the holder.

The edges of each X4 GND are then milled down smooth, and an outer-layer of protective coating is applied along the edge of the glass.

DIAMOND CASES

Each X4 GND comes with a protective diamond case. They're durable, easy to use, prevent damage when in your bag and they have unique colors so you know which you're using.