HDR (High Dynamic Range) photography is a way of capturing and processing images that allows for a wider and deeper tonal range of colors. The “Dynamic Range” is the difference between the lightest and darkest areas that you can capture in a single image. Quite often we are faced with a high-contrast scene where our eyes can see the colours and tones of both the landscape and the sky but in a single exposure the subject exceeds the camera’s dynamic range and will either blow out the highlights to pure white or silhouette or black out the dark areas of the landscape. Therefore creating multiple exposures will allow both light and dark elements to appear natural and rich in color.
One method of making an HDR photograph is to combine together multiple images with different exposures.
You may have seen many HDR images across the web and depending on how they’re processed, they can be anything from quite subtle HDRs which are accurate reproductions of what your eyes see, to quite surreal images that transform reality into a high-definition landscape.
So put simply a HDR image can be just two, three, or even more images taken at different exposure levels and then processed together using software to create a single photograph. to achieve this you need to take a range of bracketed photos with varying shutter speeds in order to produce a set of images with varying exposures. Then, with the help of post-processing software, you are able to blend the photos together and create a single image with a much higher dynamic range that the camera can take with a single shot.
To create your HDR image you will need the following equipment:
A camera, preferably with an Auto Exposure Bracketing (AEB) function. AEB isn’t totally necessary, but without it you’ll have to adjust your camera settings manually between each shot, which increases the chances you’ll move the camera, and also takes more time, which increases the likelihood that your subject will move or change positions. If your pictures don’t line up, the final HDR image wont come out quite right.
A tripod is essential in creating a HDR image, as every pixel must match between the different exposures so it simply can’t be done properly handheld.
HDR photo-blending software. There are a number of different programs that you can use to create your HDR image, and one program which is specific to the process is Photomatix. The other alternative is to to use exposure blending in Photoshop, which you can read about in our blog post here – Exposure Blending in Photoshop
Once you’ve got everything you need here are a few tips for getting a good shot:
Due to the nature of HDR and exposure bracketing, its much harder capture a moving subject or subjects, so for example a crowded street, sports ect… so look to photograph a scene that isn’t going to change very drastically in a 5-10 second period.
Try to keep an eye out for scenes and subjects that have a large, noticeable contrast between light and dark areas. This is often found at sunset and sunrise, or if the weather is quite mixed and the light is uneven. Also images of rusty cars or boats can make for quite abstract, high-definition style images.
So its then down to taking the images:
What I tend to do is get the camera set up on the tripod, and compose the subject. You want to avoid any kind of movement of the camera in-between exposures, so a cable release is also very useful. I also want a few of the settings to not change between exposures, so set the camera to the lowest ISO setting to achieve the best quality image, find the focal point and then set the lens to manual focus, so that theres no chance of the focal point changing between exposures. Then set the camera to Aperture priority and set to the depth of field you would like. Often for landscape I use a large depth of field so that from the foreground to the distance are all in focus, somewhere from f16 upwards.
Set the Auto Exposure Bracketing (AEB) depending on how contrasting the scene is and to get the histogram in at both ends. Once done you can then take the image three times and the camera will adjust the shutter speed to achieve all the bracketed exposures. If there is slight movement in the scene for example water, its best to capture the three images in quick succession.
Lastly once you have the bracketed images, its time to process them together. As mentioned previously a program dedicated to this is Photomatix which is fairly simple to use. In the program you can open the three exposures and click process, this creates a HDR image which you can then make finer adjustments and export as the finished jpeg. The other alternative is using exposure blending in Photoshop, which you can read about in our blog post here – Exposure Blending in Photoshop
If you would like to learn more about capturing HDR images then join us on any one of our workshops and we can take you through the process of taking the images to the final artwork, read about our workshops here…