Use Multiple Exposures to Capture the Full Dynamic Range
One of the biggest frustrations with landscape photography is capturing the entire dynamic range. Often, the sky turns out white while the landscape is correctly exposed and other times the landscape is black and the sky looks good. Unfortunately, capturing an over-all well-exposed image is at times not possible, therefore we have to look at other solutions, such as taking multiple exposures, to capture the full dynamic range.
If you’re a regular reader of CaptureLandscapes, you might already know that using Graduated ND Filters (GND)is one solution to this issue. You might also recall that I’ve mentioned that GND’s aren’t always the best option as they don’t take into consideration trees or other elements that go above the horizon. In cases like that (when you have mountains, trees, buildings or something else in the frame), using multiple exposures is a better alternative.
Why Multiple Exposures
While using a graduated filter is fairly easy and doesn’t require you to do any advanced techniques in post production, as I said above, it’s not always the best choice. Since the graduated part of the filter is a straight line, anything above the distinction will be affected. By using multiple exposures, you’ll eliminate this problem but it will require a bit more time and effort.
Taking multiple exposures to capture the dynamic range means that you take a series of images with different shutter speeds. Typically you take one base image, one underexposed image and one overexposed image. That leaves you with multiple images where different parts of the image are correctly exposed. Later on, these images need to be blended in either Photoshop, Lightroom or another image editing software.
How to do it in the camera
There are mainly 3 ways to capture multiple exposures in the camera; one automatic, one semi automatic and one manual. Two of these require further treatment in an image editing software but one blends automatically inside the camera. Let’s look at the pros and cons.
In Camera HDR Bracketing
Many modern cameras have a built in function called HDR Bracketing. This function, normally, lets you choose how many images you want to blend and how many stops in between each image. After capturing the series of images, the camera will automatically blend the images and give you a correctly exposed result where both the sky and foreground look correct. While this is the easiest way to bracket images, it’s also the method which results in the poorest quality.
Since the camera calculates the value for each pixel, a typical result will have a lot of noise and washed-out/fake colors. It might also look crispy and over-sharpened. Unfortunately, if you don’t have access to softwares such as Lightroom or Photoshop this may be your best option to bracket images.
The second, and most common, method of capturing multiple images is by using the semi-automatic bracketing function of your camera. This function does NOT work with M (Manual) Mode, so you need to set your camera to either Aperture Priority, Shutter Priority or Automatic Mode.
The camera has a button named BKT (varies on camera brand). This is the Automatic Bracketing (which I often refer to as Semi-Automatic. In simple words, this function changes the setting for each image. Let’s say you change the settings so you get a series of 3 images at 0.3 stops difference. The camera will then take 1 image that is 0.3 stops underexposed, another which is correctly exposed and a third image that is 0.3 stops overexposed.
You’re able to adjust both the amount of images taken in the series and how many stops difference there should be between each image.
The images still need to be blended in a image editing software afterwards.
Manually Capture Multiple Exposures
My preferred technique for capturing multiple exposures is doing it manually. Since I work with Manual mode, the automatic method mentioned above is not applicable so I need to do it manually. Honestly, I find this to be much easier but that might have something to do with the fact that I’ve solely used this method for the last years.
When you have found your base exposure (the most neutral), you need to decide how many stops you want between each image. I normally start with 1 stop but if that’s too much I’ll adjust. Let’s say that my base exposure is 1 second and I need 3 images to capture the sky and foreground correctly. I start by taking one picture at +1 stop (2 seconds), then the base exposure at 1 second and finally the last image at -1 stops (0.2 seconds). This leaves me with three images that I’ll later on blend together.
How to blend images in Lightroom
Now that we have captured multiple exposures, it’s time to blend them into one final shot which looks correctly exposed. While there are many editing softwares that let you blend images, I prefer working with Adobe Products. Softwares such as Photomatix work well but the results are often over-processed and unnatural, a look I try to avoid.
While blending images in Lightroom is much easier than in Photoshop, it does have certain limitations. That being said, Lightroom has really improved during the last years and the quality of blending there can be really good. In fact, I tend to use Lightroom for easier blends these days.
- Select the set of images you wish to blend after importing images to Lightroom.
- When selected, right click one image and choose Photo Merge -> HDR
- Adjust the settings as you prefer
- Click Merge
Lightroom will now automatically blend these layers and create a new, blended file which you can continue processing.
How to blend images in Photoshop
Photoshop has a similar function that blends images automatically but we’re not going to look at that now as it’s more or less the same as in Lightroom.
Blending images in Photoshop is a huge topic and there are many techniques, both easy and intermediate, such as Luminosity Masking and Blend-if. Since these are more advanced techniques, they will be featured in an upcoming article. Let’s look at an easier method to blend two images in Photoshop instead:
- Open the set of images you wish to blend as layers in photoshop. Make sure that the image with a correctly exposed sky is on top.
- Create a black layer mask on the top layer. This will conceal the sky layer and only the layer beneath is visible.
- Click on the black layer mask and start painting in the sky with a white brush. The white brush will reveal areas from the selected layer.
As you see, you have now blended the two layers and taken the best from each of them into one image. This is the easiest way to blend images but also the most sloppy as it’s easy to brush into areas you don’t want to affect and create a halo or visible lines. Alternatively, you can use the Quick Selection tool to make masks to paint within.
For more detailed selections I suggest taking a look at these videos from Jimmy McIntyre where you’ll learn about Luminosity Masking and how to blend images without haloing or other artifacts.
I know this is a scary subject for many but I challenge you to during the next day go out and try to take multiple exposures. Go ahead and share your result with us in the comments below, I’m excited to see what you come up with!