1. capture images for exposure blending properly, and
2. how to go about it in Photoshop.
Exposure blending is one of the best ways to create a powerful landscape image. As you’ve probably noticed, it’s very difficult to capture many landscapes accurately (especially those with a sky) because your camera sensor is limited to one aperture and one shutter speed at a time – there’s no way to have two different settings within the same image. You’ll often note that your photos rarely live up to what you actually saw – exposure blending is our way to overcome the limitations of your camera and photograph a landscape how it was meant to be seen.
Simply put, in order to have a well-exposed landscape you’ll need one image exposed for the brightest tones in your photo (typically the sky) and another for the darkest tones (the ground, usually) when the lighting isn’t suitable to capture it all in one go – think of sunsets and how differently the light is when you compare the sky to the ground. Once you have your two extremes, you’ll blend them together to make one perfectly exposed landscape. It uses the same principles of HDR photography in the sense that we’re expanding the tonal range, but exposure blending creates a more natural-looking image – and you have much more control over the end result.
On top of these two photos on the extreme end, a middle exposure (one that’s been light metered for the entire image) is good to have as well for any middle ground elements you need to blend in. Depending on the tonal range of your landscape, you may need to take several other images in between your two extreme exposures in order to ensure you have no blown highlights or underexposed shadows – it’s not uncommon to have 5 or more photos of the same scene at your disposal.
The range of your exposures will depend entirely on how bright your highlights are and how dark the shadows appear. For example, a cloudy day will have very little difference in exposure, but a sunset image may have 5 or more stops in your complete tonal range.
I love visuals so let’s look at my image below. As you can see, the setting sun is beautiful but caused some problems in exposure…the image where the foreground is exposed well (slower shutter speed) has an extremely overexposed sky, while the photo exposed for the sky (faster shutter speed) has the foreground in complete shadow. To get a proper exposure, I would need to combine these two images to get my result shown – and that, my friends, is exposure blending.
How do I do this? It’s actually quite simple once you learn the technique – and DSLRs have made it a lot easier with auto-bracketing.
When you auto-bracket a landscape, your camera will capture one photo exposed normally, then capture two more images – one directly after another – of different exposures…one exposed less than your first (base) image, and one exposed more. The difference exposure will depend on your camera and chosen settings, but usually 2 full stops is the maximum increase/decrease from your base photo.
This is where the term “auto-bracketing” comes from since you’re bracketing your images off automatically by capturing the same scene at different exposures within “X” amount of stops.
This allows you to capture three sequential images of different exposures without having to adjust your settings manually – very handy. However, for more intense differences in lighting, you’ll still have to adjust your settings manually to capture more of a range in exposure than two stops (or whatever your camera’s auto-bracketing limit is). I’ll explain how to do this in the next article, but first I want to show you WHY you should auto-bracket instead of adjusting just one RAW file.
If you’re not familiar with the benefits of shooting in RAW format, please read this article I wrote on the subject – very important!
With RAW being such a versatile format for editing, why is there a need to auto-bracket when you can simply adjust the exposure in RAW and import all the photos into one PS file? It would save you the time of setting up a tripod, taking three (or more) images, as well as save on disk space – I thought RAW was supposed to be a magical exposure recovery tool?
Just like with most post processing techniques, it’s always best to do it in-camera if possible simply because you’ll have more data in an actual photo than an image adjusted artificially – even if it’s in RAW. Auto-bracketing is better than RAW for the following reasons:
Let’s get back to the visuals – I’m going to compare a scene where I underexposed my photo by two full stops using auto-bracketing with my camera vs. dropping the exposure in RAW.
In my base image below, you can see that the foreground is exposed well, but the sky is seriously blown out (overexposed).
If I had only this one RAW file to work with and did not auto-bracket this scene, I would simply drop the exposure down by two full stops (my RAW limit) to get some of the detail back in the sky – results below.
When we zoom in, you can see a huge improvement (thanks RAW!), but there are a few blown highlights that didn’t make the cut (circled).
Instead of adjusting my exposure in RAW, I could use a photo that I actually took two stops lower with my auto-bracketing (below). When we zoom in on the detail, we can see a few important differences. First, the blown highlights have been fully recovered, indicating that my base image was overexposed a bit too much to recover all the highlights.
Secondly, when you REALLY zoom in, you can see a huge difference in pixelation and noise – the auto-bracket image wins by a long shot here (first image) when compared to the sample adjusted in RAW (second image).
While the differences here are only noticeable when viewing at 100%, it’s still an improvement in quality – it’s a better idea to spend a little more time to auto-bracket your landscape than to shoot one RAW file and adjust it as necessary.
Not only will you have less noise and pixelation, but as an added bonus you’ll really increase your tonal range for editing if you auto-bracket in RAW format – instead of being two stops in either direction of one RAW file, you can give yourself a two-stop safety net for the auto-bracket images – giving you a total range of eight stops instead of just four with one file (assuming you shoot three auto-bracket images in two-stop increments).
Blending exposures using one RAW file is best for those candid shots where you didn’t have enough time to set up a tripod but need to correct some blown highlights or simply want to brighten/darken parts of your image – like wedding or action photography. It’s still a fantastic way to save an otherwise unusable photo…but if you have the time and ability to auto-bracket your landscape for exposure blending, always do it!
One final note: exposure blending is not just for combining bright skies with dark grounds – you can use it in many different ways. You can recover blown highlights in water reflections, use it as a no-damage way to dodge and burn your landscapes, or perform many other editing techniques where you may need different exposures of the same subject.
But first, you need to know how to get those exposures to begin with. In Part 2, I explain step-by-step how to capture different exposures the right way using a tripod.
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Superb website packed with great photo’s and really useful imformation. thanks for taking the time to put it together