How to Use Graduated ND Filters

To use a graduated ND filter, put the camera on a tripod and compose, meter the sky and the foreground separately, and pick a grad whose strength in stops roughly matches the difference. Slide the dark half down in its holder until the transition sits on the horizon, set the exposure for the foreground, and check the histogram. The filter holds back the bright sky so one frame keeps detail in both the sky and the land.

A graduated neutral density filter, often called an ND grad, a GND or a graduated neutral filter, is a sheet of glass or resin that is dark gray across one part and clear across the rest, with a transition zone between them. It exists because the sky is usually much brighter than the ground, often by more than the camera’s dynamic range can hold in one exposure. Expose for the land and the sky turns white; expose for the sky and the land goes black. A grad closes that gap at the moment of capture, which is why it is a staple of landscape photography. Unlike a plain ND filter, which darkens the whole frame evenly, it darkens only the part you place it over. This page is about using one well.

How to Use an ND Grad, Step by Step

1. Set up on a tripod and compose. The filter has to line up with the horizon, and that only stays put if the camera does.
2. Switch to manual exposure. In aperture priority the camera will brighten the whole frame when it sees the darker sky through the filter, undoing some of what the grad does.
3. Meter the foreground. Spot meter, or fill the center of the frame with, a midtone in the land such as grass or rock. Note the shutter speed at your chosen aperture and ISO.
4. Meter the sky. Meter a bright part of the sky, but not the sun or the area right around it. Note this shutter speed too.
5. Count the stops between the two readings. Each halving of the shutter speed is one stop. That difference tells you how strong the grad should be.
6. Choose the grad. Use the strength that closes most of the gap. If the difference is three stops, a two or three stop grad is right. A little under is better than over.
7. Slide it into place. With the dark part at the top, lower the filter until the transition rests on the horizon. Check it in live view, or press the depth of field preview button, at your working aperture.
8. Set the exposure for the foreground and take the shot. The clear part of the filter does not change the land, so the foreground reading stays correct.
9. Check the histogram and the highlight warning. The sky should no longer be clipped and the shadows should still hold detail. Adjust the filter position or strength and shoot again if needed.

How Grads Are Rated: Stops, Density and ND Numbers

The strength of a grad describes its darkest part. It is labeled in one of three ways, and they all mean the same thing. Each 0.3 of optical density is one stop, which halves the light.

Stops	Optical density	ND number	Light let through	Typical use
1	0.3	ND2	1/2	Subtle balancing, overcast days
2	0.6	ND4	1/4	Bright overcast sky, sky behind you
3	0.9	ND8	1/8	Sunrise and sunset, sky toward the light
4	1.2	ND16	1/16	Shooting into a bright sunrise or sunset

A two stop and a three stop grad cover most landscape situations. Two grads can be stacked in the holder when the difference is bigger still: a two stop over a three stop gives five stops in the area where both overlap.

Hard, Soft and Reverse Grads

Grads also differ in how quickly they change from dark to clear. Choose by the shape of the horizon.

• Hard edge. The change from dark to clear is abrupt. It suits a flat, clean horizon such as the sea or a prairie, where you want the full effect right down to the skyline.
• Soft edge. The change is gradual over a wide band. It is far more forgiving when hills, trees or buildings break the horizon, because there is no sharp line to give the filter away. A soft grad is the most useful single grad to own.
• Reverse. Darkest in a band at the transition and lighter toward the top. It is made for sunrise and sunset, when the brightest part of the sky is the strip just above the horizon.

How hard the transition looks also depends on the lens and aperture. On a wide-angle lens at a small aperture the edge looks sharper, so a soft grad behaves more like a hard one. On a telephoto lens the lens sees only a small part of the filter, so the transition is stretched across much more of the frame and even a hard grad looks soft, and a soft grad can spread its effect so widely that it does little. This is why you check the position at the working aperture rather than wide open.

The Holder System

Most grads are rectangular and slide into a holder that clips onto an adapter ring screwed into the lens’s filter thread. The rectangle is taller than it is wide so you can move the transition up or down to wherever the horizon falls in your composition. The holder also rotates, so you can tilt the transition to follow a sloping horizon or a diagonal line of hills.

Round screw-in grads exist, but their transition is fixed across the middle of the frame. Unless your horizon sits exactly there, they darken the wrong part of the picture, which is why a slot-in system is the usual choice. Buy adapter rings for each lens thread you use so one holder fits all your lenses, and choose a holder wide enough that it does not show in the corners of your widest lens.

Not sure which filters belong in the bag beside a grad? Camera lens filters explained covers what each type does and whether editing can replace it.

A Worked Example

Suppose you meter the bright sky and get 1/15 second at your chosen aperture, then meter the foreground and get 1/2 second. From 1/15 to 1/8 to 1/4 to 1/2 is three stops. Exposing for the foreground at 1/2 second would place the sky three stops above a midtone, which is at or past the point where its brightest parts clip. A three stop (0.9) grad placed over the sky closes that gap, and you shoot at 1/2 second, the foreground reading. If you only carry a two stop grad, use it and recover the last stop in editing, or bracket and blend. Recheck the histogram after positioning the filter to confirm the sky is no longer clipped.

Grads With Other Filters

With a polarizer. A polarizing filter cuts glare on water and foliage and deepens a blue sky, and it works well alongside a grad. Rotate the polarizer first, then place the grad. On a wide lens the two together can darken the corners, so check the edges of the frame.

With a solid ND filter. For a long exposure of moving water or clouds, a solid ND filter lengthens the shutter speed while the grad balances the sky. Put the solid ND in the slot closest to the lens, where its gasket seals out stray light, and the grad in front where you can slide it. During long exposures, cover the viewfinder eyepiece if your camera has an optical viewfinder, or light entering it can fog the frame.

Flare and color casts. Every filter adds surfaces that can catch light, and a gap between filters lets light reflect between them. Shade the front of the holder with your hand or a hood when the sun is to the side. Some resin grads are not perfectly neutral and add a slight color cast, usually warm or magenta, which a white balance correction removes.

ND Grad or Digital Blending?

A grad is not the only way to handle a bright sky. On a raw file, a linear gradient mask in an editor does a similar job after the fact, as long as the sky was not clipped to pure white. Bracketing several exposures and combining them with exposure blending or HDR handles even bigger differences, and a hand-drawn mask can follow a jagged skyline that no straight filter edge can.

The grad still has real advantages. It gives you a balanced single frame, so moving water, waves and clouds do not have to be merged across several exposures. You can judge the finished balance on the camera’s screen in the field. And the shadows need less brightening later, which keeps noise down. Many landscape photographers use both: a grad to get close in the field, and a gradient or mask to finish. Masking and selective adjustments covers the digital side.

Would several exposures serve the scene better than a filter? Exposure blending walks through shooting the brackets and combining them by hand.

Common Mistakes With Graduated ND Filters

• A hard grad over a broken horizon. Mountains, trees and buildings that rise into the sky turn dark at the top. Use a soft grad, or blend exposures.
• The transition in the wrong place. Too high leaves a bright band above the horizon; too low darkens the land. Line it up in live view at the working aperture.
• Too strong a grad. A sky darker than the land looks wrong, because in nature the sky is almost always the brighter of the two. Choose a grad slightly weaker than the measured difference.
• Leaving the camera in an automatic exposure mode. The meter sees the darkened sky and brightens everything, so the foreground comes out too light and the grad’s effect shrinks. Set the exposure manually from the foreground reading.
• Forgetting that the light is changing. At sunrise and sunset the difference between sky and land can change within minutes. Meter again every few frames.
• Not checking the corners. A holder, or stacked filters, can show as dark corners on a wide lens. Zoom in on the corners of a test shot.

Try This: Measure the Gap

This takes about 10 minutes and works even without a grad. On a bright day, find a scene with open sky above a darker landscape. In manual mode, spot meter the land and then the sky, and count the stops between them. Take one frame exposed for the land and one for the sky, and look at the histogram for each. If you have a grad, take a third frame with it in place and compare all three. If you do not, apply a linear gradient to the sky of the first frame in your editor and see how much detail comes back. Either way you learn how big the gap usually is in the scenes you shoot, which tells you which strength of grad you would actually use.

Frequently Asked Questions

How do I use ND grad filters?

Meter the sky and the foreground, choose a grad that matches the difference in stops, and slide it down until the transition sits on the horizon. Then set the exposure manually for the foreground and check the histogram. A tripod makes the positioning much easier.

Hard, soft or reverse grad: which do I need?

Hard edge for flat horizons such as seascapes, soft edge for horizons broken by hills or trees, and reverse for sunrises and sunsets where the brightest light sits on the horizon. A soft two or three stop grad is the most versatile single filter.

What strength of graduated ND filter should I buy first?

A three stop (0.9) soft grad handles the widest range of landscape light, including most sunrises and sunsets. A two stop (0.6) is a good second filter for gentler light, and the two can be stacked when the sky is very bright.

Can I just fix it in editing instead?

Often yes, with a gradient on a raw file, exposure blending or HDR, especially when the horizon is irregular. A grad still helps by capturing a more balanced single frame, which means less work and cleaner shadows in editing, and it keeps moving water and clouds in one exposure.

Screw-in or square filter system?

A square or rectangular system in a holder is far more flexible, because you can slide and tilt the transition to match the horizon. Screw-in grads lock the transition to the center of the frame, which rarely lines up with your composition.

Do I need a graduated ND filter for sunsets?

Not always, but it helps. When you shoot toward a setting sun, the sky can be four or more stops brighter than the land. A three stop grad, a reverse grad, or bracketed exposures keep color in the sky without turning the foreground into a silhouette. How to photograph sunsets covers the rest of the technique.