Capturing images that are well exposed in both the foreground and sky isn’t as easy as one would think. In fact, it’s a common problem when working with high-contrast scenes.
Too often we find that the sky is blown out when we expose for the landscape. Exposing for the sky leads to a too dark foreground.
Maybe this sounds familiar. If so, know that you’re not alone. This is one of the most common difficulties landscape photographers face.
The benefit of it being a known problem is that the solutions already exist.
In this case, there are two main solutions: Exposure Blending (Advanced) and Graduated Neutral Density Filters (Easy)
It’s the latter that we’re going to look closer at today. These filters are a favorite amongst landscape photographers as they make it easy to capture well-exposed images.
Keep reading and you’ll learn exactly what Graduated Neutral Density Filters are, why they’re loved by photographers, how to use them and which models to choose.
What are Graduated Neutral Density Filters?
Let’s start with the obvious question: What are Graduated Neutral Density Filters?
If you’ve read our article Why Neutral Density Filters Will Improve Your Photography, you may already have an idea.
A Graduated Neutral Density Filter (simplified as GND) is a partially darkened filter that’s placed in front of the lens.
The purpose of the darkened part is to allow less light to reach the camera’s sensor. Just as a regular Neutral Density Filter does.
What differentiates these two filters is that only the top part of the GND is darkened. The rest is transparent. This means that the filter allows you to darken a part of the frame while the rest is unaffected.
In other words, it can balance the exposure by darkening an otherwise over-exposed sky.
Types of Graduated Neutral Density Filters
This is where things get a little confusing. So, buckle up and make some notes; There isn’t just one type of GND filter. They come in many shapes and variations.
It would be convenient if you only had to deal with one specific set of filters for every situation. Reality is quite different. First off, you have three different types of transitions: Soft, Medium, and Hard. Then you have degrees of darkness: one-, two-, or three-stop. You have ordinary versus reverse filters, screw-in versus square, different materials, and a wide range of manufacturers.
Ugh… Where do you even begin? Let’s find out.
Drop-In vs. Screw-On
The first decision you have to make is whether you want a screw-on or drop-in (often referred to as square filters) system. This decision will impact all your filters, so give it some thorough thought before deciding.
Head over to my article How to Choose Your First Filters (and Which Systems to Use) to learn more about the differences and what you should choose.
Both systems have their pros and cons but when it comes to Graduated Neutral Density filters, there’s one that’s preferred: drop-in filters.
A drop-in system allows you to slide the filter up or down without moving the camera. This means that you can position the dark-to-transparent transition along the horizon. A circular, or screw-in, filter is fixed on the lens. Meaning that you have to move the camera in order to align the transition and horizon.
Soft Edge vs. Medium 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 three variations; soft, medium and hard edge.
This defines the transition between the darkened- and transparent parts of the filter. If you look at the picture above you can see a difference between the right and left filters.
To the left, you have a Hard Edge GND Filter. In this, the transition between the neutral density and clear glass is hard and there is no “in-between”.
The filter to the right has a smoother transition between dark and clear, making this a Soft Edge GND Filter. The smoother transition means that the darkened area has a less distinctive beginning and end.
A Medium GND Filter is somewhere in between the soft and hard.
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.
If you are to only choose one, my recommendation would be to get a medium edge as it works fine in most situations.
Reverse Graduated Neutral Density Filters
The final option you have is a Reverse Graduated Neutral Density Filter.
Just like a normal GND, the reverse graduated filter is only partly darkened. The difference is that instead of the darkest part is 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 Neutral Density 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 an 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 at the end of the darkened area. By aligning the darkened edge with the horizon you get a correctly balanced image; avoiding overexposure while maintaining details in the upper sky.
When to Use Graduated Neutral Density Filters
The power of Graduated ND Filters is that they can correct an otherwise overexposed sky. The problem, however, is that it might also darken elements you don’t want.
Why is that?
It’s quite simple; the filter has a horizontal transition between the dark and transparent areas. This means that anything above the transition will be darkened. This is great if you have a flat horizon with no projecting elements but it’s problematic if there are trees, buildings, or mountains in the image.
Anything that projects above the horizon will be affected by the filter. Just because the sky needs darkening, doesn’t mean that the mountains do too.
Let’s take a look at some examples of when Graduated Neutral Density Filters do and do not work:
Situations the Filters Work
As mentioned already, a Graduated Neutral Density Filter works best when there aren’t any elements projecting above the horizon. Now, that’s not to say that the horizon needs to be completely flat.
Keep in mind that there is a difference between the hard, medium, and soft versions. A hard version will leave a visible transition between darkened and transparent while a soft one is more forgiving.
The image above is a perfect example of when a hard edge filter can be used. Since the horizon is flat, you can easily align the filter along with it. You don’t need to worry about visible transition lines.
Now, what was the purpose of a filter in this case?
I shot the just after sunset. The sky was very bright compared to the foreground which was rather dark. Without a filter, this resulted in blowing out (overexposing) the sky when exposing for the sea stacks.
Using a graduated filter (in this case a 3-stop hard grad), I was able to bring back the details and colors in the sky, while keeping the foreground exactly as bright as I wished.
Note: Keep an eye on the histogram to make sure you’re not over or under-exposing the image.
This might be a little less obvious. At first glance, you might say that this is a no-go for GND filters. The church spire and the hills create an uneven horizon. Yet, it’s all within an acceptable distance.
A hard edge filter would not work in this case. You would see a very visible transition line along with the photo. You could place the transition just above the reflections but that would darken the trees and church too much too. It was mainly the sky that caused the problem.
Ideally, I would’ve used a soft edge filter when capturing this. The smooth transition would do the job without leaving any trace of use behind.
But, for a while now, I’m only carrying a medium edge. This has become my favorite Graduated Neutral Density Filter for many reasons. Luckily for me, it worked just fine for this shot as well.
Let’s look at one last image that a graduated filter works on. Yet again, we have a relatively even horizon. It’s just a few areas that project just above it. These areas might be enough to make a hard edge problematic, but both a medium and soft edge filter will do the job.
Situations the Filters Don’t Work
You might already have an idea of which situations a Graduated Neutral Density Filter won’t work for your photography. Let’s take a quick look at some examples, just to clarify:
After a really intense sunrise on Iceland, I stumbled across this abandoned building while walking back to the car. There was something fascinating about the scene and I soon thought that it would be a perfect example for an article just like this.
As you can see, the skies are totally washed out and the picture is rather boring. With a sky this bright it was impossible to capture the full dynamic range. A GND filter solves the sky issue but, as seen on the picture below, it’s made the house almost entirely black as well.
On top of that, you can see that parts of the foreground is darkened too. This is due to my filter not being completely straight. Just a small error can make a big difference.
Here is one more example of when using a Graduated filter didn’t work. Yes, the sky might be good but the trees are now pure black:
An Alternative to Graduated Neutral Density Filters
The good news is that all hope isn’t lost in cases where a filter can’t be used. In fact, there are several alternatives (alternatives that many photographers swear by regardless of the situation)
Option #1: Exposure Bracketing
Capturing multiple exposures and blending them together in post-processing is a popular technique that many photographers frequently use. In fact, there are many photographers who prefer this method over GND filters in any scenario.
The technique is slightly more advanced and requires a basic understanding of layers and masks in Photoshop or another photo-editor.
Simply put, this technique requires you to capture two or more images of different exposures (i.e. one under-exposed, one regular, and one over-exposed) In post-processing, you then take the correctly exposed parts from each image, and blend them together to one final file.
Option #2: Take Advantage of the Camera’s Dynamic Range
Today’s cameras are getting better and better. The Dynamic Range is among the factors that have drastically improved during the last years. It’s almost unrecognizable compared to cameras only 5 years old.
What this means for you, is that you’re able to bring out a lot of information in the shadows during post-processing, without introducing high amounts of noise.
In cases where there’s a significant contrast between the sky and landscape, expose your image for the sky. Keep an eye on your histogram to make sure that you’re not clipping the highlights (but keep the highlights as far to the right as possible without touching the edge)
This will most likely lead to a quite dark image overall but in your RAW editor, you can increase the shadows and bring back those beautiful details.
Note: this option won’t work when there is extreme contrast between highlights and shadows, and it heavily relies on the quality of your camera. I suggest trying this on various occasions to see how well the Dynamic Range of your system is.
Graduated Neutral Density Filters can make a huge difference to your landscape photography. They have the power to instantly correct an over-exposed sky while leaving the rest untouched.
However, there are situations where the filter can do more harm than good. Obvious transition lines are big red flags and something that will make your images look a lot less impressive.
It’s also important to understand that you don’t need these filters. You’ll be perfectly able to capture impressive images without. However, that will most likely require more time in post-processing.
What a Graduated Neutral Density Filter helps you with is getting the best possible results in-camera. In my opinion, that is part of making life just a little easier. Which I’m not going to say no to.
Do you use Graduated Neutral Density Filters? Or perhaps you swear to other alternatives? Let us know in a comment below.
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