One of the most common questions I get asked regarding photography is how to get both the foreground/landscape and the sky properly exposed. Either the sky is completely white or the landscape is too dark. You might have experienced this yourself, and perhaps you’re also struggling to get the entire image correctly exposed. There are two solutions to your problem: Blending multiple images and Graduated ND Filters.
Graduated Neutral Density Filters have become a valuable tool for most photographers. In this article you will learn what they are and how to use them.
What are Graduated ND Filters?
If you’ve read my introduction to Neutral Density filters: Why Neutral Density Filters Will Improve Your Photography, you may have an idea of what Graduated ND’s (GND) are.
A Graduated ND Filter is a dark glass or resin placed in front of your lens. Just like a normal ND Filter it allows less light to enter the camera. What differentiates these two filters is that the GND is only partly darkened. That means that the filter only darkens parts of the image while the remaining half is left alone.
Graduated ND’s are available in three degrees of darkness, one – two – and three stops. To clarify; this means that some of the filters allows more light to go through than others. At this moment you may ask yourself why in the world you would only darken parts of a image, but I’ll come back to that in a bit!
Soft Edge vs Hard Edge
You already know that graduated filters are delivered in three different strengths. What you may not yet know is that they are also made in two variations; soft edge and hard edge.
This defines the transition between the darkened- and clear parts of the filter. If you look at the picture above you can see the difference between the right and left filter. To the left you have a hard edge Graduated Filter where the transition between neutral density and clear glass is hard and there is no “in between”. The filter to the right has a much smoother/softer transition between dark and clear, making this a Soft Edge filter.
I wouldn’t say that one is better than the other. It depends on the situation which one you want to use. If the horizon is even, a hard edge may be preferred. When the horizon is less even, you may prefer a soft edge to ease the transition and reduce the risk of getting a very obvious hard line. However, if you are to only choose one, my recommendation would be to get a soft edge as it works fine in most situations.
Reverse Graduated ND Filters
If you have heard about Graduated filters before, you may have also heard the term Reverse ND Grad. Just like a normal GND a reverse graduated filter is only partly darkened. The difference is that instead of the darkest part being at the top and the brightest in the middle, a reverse GND is the other way around.
Say that you have 3 stop Reverse Graduated Filter. The darkest point (3 stops) would be at the transition to clear glass, while the top of the filter would only be 1 stop. In other words it allows more light to enter the top of the darkened part than the bottom – while the lower half is still clear.
This filter is normally used when the sun is about to set, and the light just above the horizon is bright. A normal graduated filter would have done a ok job but most likely the top of your image would be very dark, since this is where the darkest point of the filter is, while the horizon may still be bright.
As I mention it’s darkest in the end of the darkened area. By aligning the darkened edge with the horizon you get a correctly balanced image; avoiding a overexposed while maintaining details in the upper sky.
When to use Graduated Filters
Even though graduated filters can make an overexposed sky correct, it’s not always the best option. Remember that the transition between darkened and clear part of the filter is defined by a horizontal line. Anything above the line will be darkened.
This is not something you want in every picture. If there is a mountain, tree or head of a person above the horizon this will also be affected. It may quickly ruin what could have been a great image, so let’s take a look at some examples for you to get a better understanding of what I’m explaining.
When it works
The image above is a perfect example for when a hard edge grad should be used. Since the horizon is flat I can align my filter with it. This picture was taken just after sunset, while the sky was very bright. The foreground however was rather dark, which led to a big contrast between the sky and beautiful cliffs. To balance the image, I used a 3 stop graduated filter to get back the details and colors in the sky, while keeping the foreground exactly as bright as I wished.
This might be a little more tricky. Yes, the horizon is relatively straight, but you need to be careful not to get a obvious edge along the trees. Typically this would be a great time to use a Soft Edged filter so you avoid the hard edge.
When taking this shot the sky was much brighter than the water, but the reflections were perfection! Getting both a perfect sky and the reflection in one shot would have been impossible without a filter.
I told you that this scene would be great with a Soft Edged filter to get a smooth transition around the trees. Well I went for a Hard Edged filter. Badass me right!? Instead of aligning the filter above the trees I did so on the transition between land and water. The reason I placed the edge here rather than over the trees was because the trees were brighter on land than in the reflections. Doing this I evened out the light and got a similar exposure on both of them.
Take this into consideration when you go out shooting; there is no blueprint on how to use filters. Try to imaging how the end result will be and evaluate the light. Also if you own both a hard and a soft edge filter there is no harm in trying both!
Let’s look at one last image that a graduated filter works on. Again not an obvious one. At first thought you may think that graduated filters are not suitable because of the mountain. Well, as I said a moment ago; there is no blueprint and sometimes you just got to try!
Since the mountain is above the horizon and the horizon is straight, you can use a graduated filter. The entire mountain is above the horizon so you wont get any hard transitional lines on it when aligning it and the filter.
In this case I used a Reverse ND Grad as the sun was very bright on the right side of the frame. The Reverse ND Grad allowed me to get rid of the washed out highlights while maintaining desired brightness in the upper parts of the sky.
Be aware that this is a scenario while using a software such as Lightroom might be needed afterwards to increase shadows since the mountain might be darkened a bit more than ideal.
When it doesn’t work
As you may begin to understand; graduated filters are not recommended for every photo. It’s clever to avoid using filters when you have a lot of mountains, trees or just an uneven horizon. Let’s look at some examples on when to avoid using them so you get a better understanding.
After a really intense sunrise on Iceland I was hiking back to the car and past this abandoned house. Something about the scene really appealed to me and I had to stop for a moment. While taking a couple of shots I figured this would be a perfect example for an article just like this.
The skies are totally washed out and the picture is rather boring, as you can see on the first picture. With a sky this bright it was impossible to capture the full dynamic range.
In the next picture it’s the opposite problem. The sky is much better but the house is almost completely black! You can also see that my filter is covering some of the ground right next to the house, as my filter wasn’t kept straight.
This is a good example on when a filter might not be the right choice. I’m not going to talk about post processing now, but there are techniques to work around this problem; such as blending multiple exposures. Also it is fairly easy to recover highlights or brighten shadows in softwares such as Lightroom. But this is a huge topic for another time!
Hopefully you have learned more about graduated filters in this article. Like I mentioned earlier, there is no right and wrong. Trying and failing is always the best way to learn.
If you take into consideration the points I’ve mentioned above, such as when filters are recommended and not, I am sure you soon will see improvement in your photography. Graduated filters are great to use and can help you achieve amazing results. Yet, as you now know, they are not always the best option and there are other ways to achieve the same results, such as blending images.