What is a GND?

GND is short for Graduated Neutral Density, which is a rectangular filter that 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.

How It Works

Outdoor photographers frequently struggle with dynamic range, as the human eye can see over 20-stops, while a mid-day outdoor scene may only range between 15-18 stops.

Professional camera systems span between 12-15 stops and during the last decade very little progress has been made to close the gap between the sensor and what the human eye sees.

GNDs expand in-camera dynamic range.

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 can cover that exposure gap (12 + 2 + 3 = 17). Without the GNDs, the full range of the scene would be 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 central to the best sunset scenes.

A new generation of GND.

Legendary landscape photographer Galen Rowell developed the GND filter with Bob Singh, founder of the American filter manufacturing company Singh-Ray. Together they pioneered a method for covering the dynamic range gap of 35mm film.

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 unmatched resolving power.

The X4 GND goes beyond as the world's first GND to use tempered glass. The result is the most durable GND on the market. And by using SCHOTT B270® optical glass, the X4 GND resolves critically sharp.

Incredible durability.

Another benefit of our manufacturing process is that the optical surface does not degrade over time with exposure to corrosive elements common to outdoor photographers such as salt water and sand.

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

State-of-the-art coating technology.

Traditional CR-39 resin have exceptional sharpness if the surface is in mint condition. However CR-39 proves to be a poor material for accepting coatings which leaves industry leading CR-39 GNDs by Singh-Ray and Lee without MRC or nano coatings.

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

After the coating process, the edges of the X4 GND are milled down smooth and an outer-layer of protective coating is applied along the edges of the glass.

Diamond Cases

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