This is the second part of the HDR tutorial and will cover the worflow to produce HDR photography. Please make sure your read the first part where we covered some basic definitions and terminology!
The most important thing in HDR photography is the quality of the bracketing. If you have good images at the begin of the process, you will have a good HDR result at the end.
What do you need?
- A Camera with AEB (Automatic Exposure Bracketing)
- Tripod (It's recommended to use a tripod to avoid movements and blurred image due to long exposures.).
- Shutter remote control to avoid vibrations (optional)
- HDR software to process your images (like Photomatix)
How many Brackets do I need?
The number of images required to cover dynamic range of a scene varies from place to place. However, those images should cover as much luminosity as possible from the brightest to the darkest parts of the frame.
Sometimes 3 shots will do, sometimes 5, 7 or even more. Of course, the number of images depend on the EV spacing between the shots of the sequence but most popular steps are 1.0 and 2.0 EV. Usually 1.0 EV will give smoothest tonal gradations. That is what we recommend!
Below there is a table with some of the most common types of scenes and number of exposures needed to properly capture them.
|Scene Type||Number of Stops with 1.0 EV||Number of Stops with 2.0 EV|
|Landscape on foggy day or clear sky||3 to 5||3|
|Landscape on sunny day||5||3|
|Landscape on sunny day with high contrast||5 to 7||3|
|Sunset/Sunrise||7 to 9||Not recommended|
|Forests with deep shadows and light shafts||5 to 7||Not recommended|
|Interior photos without windows||5 to 7||Not recommended|
|Interior photos with windows or doors||7 to 9||Not recommended|
This are the recommended setting for your camera.
- File format: RAW (recommended) or JPEG
- ISO: as low as possible (ie 100) to avoid noise and to have a maximum of dynamic range. Never automatic ISO!
- White Balance: fixed value (e.g. Sun or 5500K). It has no impact on a RAW file, but all the brackets will have the same value.
- Shooting mode: manual or Aperture
- Exposure bracketing: 1.0 EV or 2.0 EV. Number of shots depend on the scene (see above)
- Aperture: depending on the scene (>8 for landscapes).
- Focus: Switch to manual once in focus to avoid the focal point changing between shots.
- Initial exposure: check the right exposure - this will be your 0EV.
Checking the results
You can preview the brackets on your camera display. We recommend to check the histogram for the most underexposed shot and for the most overexposed.
For the most underexposed shot, the histogram should look like this:
For the most overexposed shot, the histogram must look like this:
The HDR-World is not perfect, there are some issues that you might encounter.
The vertical and horizontal movement between the shots of the bracketed sequence. This can cause issues with photo alignment.
To minimize this movement it is necessary to use a sturdy tripod and to use remote shutter release as mentioned before.
Ghosting is caused by the subjects moving between shots: people walking in the scene, grass blades waving, flowing water etc. You can't do much about ghosting, but some HDR software like Photomatix can help fixing this problem.
In simple terms chromatic aberration manifests itself as color fringing. Unfortunately, HDR Softwares increase this effect during tone mapping. We suggest to correct the chromatic aberration before processing them with the HDR software.
HDR is a strong tool to manage extremely high contrast like sunsets or interiors.
However, it is not necessary to use HDR in every situation. The sensors of modern cameras have a high dynamic range, so that you can cover the luminosity range of most of the scenes.
So the question is: When you should NOT use HDR?
We can provide 3 situations:
1. When you are shooting a scene that is low in contrast, you do not need to do HDR.
2. Silhouettes. A scene where you actually want part of your image to be clipped.
3. Just to make your image POP. You cannot transform a bad image into a good one using a processing technique, HDR included.
So remember: Use HDR as a tool in your photography arsenal, not on every image and every scene.
Photos and tutorial credits: philta22