HDR Photography...Understanding High Dynamic Range Photography and How to Create Stunning HDR Images.
HDR photography or High Dynamic Range Photography is an increasingly popular form of photography that allows a photographer to overcome exposure limitations and produce pictures with greater tonal range and detail.
A HDR Photo displays a larger overall range of tones or luminance values than a normal picture. Therefore HDR photos will often have a more “realistic” look to them as they can come much closer to displaying the tonal range that the human eye sees.
Many people who see HDR images might not know what they are or how they are created, but they nevertheless recognize the value of High Dynamic Range Photography and its benefits for presenting stunning realistic and even surreal images.
If you have ever looked at a landscape photo you just took and wondered why it seems so different from what the scene looks like to your eye then you might want to explore the fun world of High Dynamic Range Photography.
What is HDR Photography
Understanding the value of HDR Photography begins with understanding what dynamic range is and the limitations of a conventional photo to display the full dynamic range of a scene.
In photography dynamic range is simply the range of luminance values in a scene from the darkest point to the brightest point and is often expressed in a ratio.
For example the average outdoor sunlit landscape has a very high dynamic range (100,000:1). Out of that range the typical human eye is able to perceive or “see” a smaller dynamic range (10,000:1), but a digital camera is only able to capture an even smaller dynamic range (400:1).
So the dynamic range of the average human eye is considerably greater than the dynamic range that either a film or digital camera can capture. To complicate things even more the dynamic range of the average computer monitor or photo printer is even less than that of a digital camera.
In other words our eyes see a greater range of tones or luminance values than the normal camera can capture in a single exposure.
Therefore if we want to produce a photo that shows close to the full tonal range we are able to see we must overcome the limitations of the camera and increase the dynamic range of our photos, thus the name High Dynamic Range Photography.
At its simplest High Dynamic Range Photography is the process of increasing the dynamic range of a photo so a fuller tonal range is displayed and printed. This is done through a two-step process.
- First is the creation of a High Dynamic Range Photograph that is stored in a specialized 32-bit file instead of the typical 8 or 16 bit image file. The larger 32 bit file allows more image data to be captured and thus the photo has more dynamic range.
- The second step is what is known as “tone mapping” where this specialized 32 bit HDR file is converted into a standard 8 or 16 image file that retains the look of a high dynamic range image.
How to Create a HDR Photo
There are several ways of increasing the dynamic range of a photo and producing an HDR image.
The most common and what might be considered by some as “true” HDR Photography involves taking several photos at different exposure values and then using photo editing software to merge them together into a single HDR image. This image is then “tone mapped” to produce a High Dynamic Range photo that can range from realistic to surreal depending on how the image is processed during the “tone mapping” part of the image processing.
Another common method is to “create” different exposures from a single RAW file. Because the RAW file format contains the full uncompressed image data it lends itself well for using a single RAW image to create “different exposures” that bring out details in the shadow and highlight parts of the photo. These “different exposure” files are then merged together using the same process as the multiple exposure or “bracketed” images directly from the camera.
Yet a third method is to take a slightly underexposed JPEG image and then use some of the advanced editing features available in some photo editing software and creating a HDR-“Like” photo from that single image.
Because High Dynamic Range Photography normally involves multiple images taken at different exposures it is best used for static scenes such as landscapes, buildings, etc. Subjects with movement will cause ghosting when combining several exposures together so they are not well suited for multiple-image HDR Photography.
However it is possible to use techniques and software that allows you to expand the dynamic range of a single exposure image which I will cover in some of my upcoming HDR Tutorial’s and Software Reviews.
Finally as the last part of the post processing workflow you make the normal exposure, saturation, contrast and brightness adjustments.
]h2 dotted]The Advantages of HDR Photography[/h2]
High Dynamic Range Photography has several advantages for photographers of all levels.
Not only does it allow the photographer to capture and display an image that is closer to what the human eye actually sees but it also allows almost endless creativity for making “artistic” photos.
Depending on the post processing and the adjustments that are made to the final image you can create photos that look almost like paintings or other surreal effects. High Dynamic Range Photography makes it relatively easy for photographers to produce photos with that special “wow factor” that really capture people’s attention.
Because most digital cameras are capable to being used to create HDR images getting into HDR photography usually does not require much money.
There are some excellent affordable software programs and even a few free ones that have the ability to create HDR Photos which makes this type of photography easy to get started.
HDR Photography is very fun and rewarding to do. If you have not tried it I would encourage you to do so. For additional information be sure to check out our section on HDR Software as well as additional information on creating HDR Images.
Learning More about HDR Photography
There are several good ways to learn more about the exciting world of HDR photography.
There are many good video tutorials available on You Tube and I have included some links to those on my HDR Photography Video Tutorial page. Also there are several books on HDR Photography available from Amazon.
Finally there are also some excellent tutorials and courses on HDR Photography available from people like Trey Ratcliff from Stuck on Customs. He has a real mini-course in HDR Photography that comes with 11 lessons complete with sample files for you to use as you learn in depth post processing techniques.