October 7 2014
There is often a greater range of light captured in raw photo data than is revealed in standard digital photos. Including High Dynamic Range processing in the digital workflow helps photographers extract more details from their raw photo files.
I find using the well known HDR app, Photomatix Pro, in conjunction with Adobe Lightroom simplifies the processing and the management, of photo files created for the HDR process.
Normal HDR processing in Photomatix Pro needs at least three versions of a scene, each with different exposure settings. However, Photomatix Pro will work with a single file, for HDR processing.
Single shot HDR processing is not a rescue mission. The technique does not work on all photos, it is suited to images with slightly underexposed areas. These result from setting the correct exposure for a brightly lit area, leaving a significant part of the composition slightly underexposed. Particularly those photos with a good range of light intensity, such as dark areas or clouds. HDR processing cannot put in what is not there, it only bring out the inherent content of the image.
If the photo is overexposed with resulting blown highlights then it is impossible to get the detail back. Working with the raw image data does give some leeway to recover details from slightly overexposed images. Usually it is better to ensure the highlights are properly exposed, hence the popular expression “expose to the right” referring using the camera’s histogram as an exposure guide.
Simple evenly lit scenes are better adjusted in Lightroom. Where dynamic range is a problem, then HDR processing is a useful tool. There is a limit to the amount of image information you can successfully extract from a single photo, so there still is a place for taking a set of images with different exposure settings for HDR processing.
Simple HDR processing starts with saving the photo in raw format in the camera. This retains all the image information for later computer processing using two specialist software apps, Adobe Lightroom and Photomatix Pro.
One of the advantages of Photomatix Pro is the ease of accomplishing complex exposure adjustments that require complex processing in Photoshop Creative Suite. HDR processing performs selective editing based on tonal values rather than limiting adjustments to specific areas of the image.
The first step is using Lightroom to view and select photos that are suitable for single shot HDR processing. In Lightroom the only processing I do at this stage is applying noise reduction in Lightroom’s detail panel in the Develop module. The digital noise might not be obvious but HDR processing of darker areas can accentuate any noise.
Sending the photo file from Lightroom to Photomatix Pro is accomplished using the file menu to open the export dialog box. This allows direct access to the Photomatix Pro plugin for Lightroom. This opens Photomatix Pro and sends it a temporary tiff image file for HDR processing.
Photomatix does the initial HDR processing before photographers make the final adjustments to the photo. Photographers can save the final version and re-import it back to Lightroom. The result is two photo files in the computer. The original source file is retained, with the HDR processed version saved in TIFF format and also included in the Lightroom catalog alongside as the source image. The intermediate TIFF file created by Lightroom and exported to Photomatix Pro is discarded when the processed version is saved.
There are many potential adjustments in Photomatix Pro. Where the purpose is for quick simple adjustments of a single shot photo I only use some of them.
For single shot HDRs Photomatix Pro only uses the Tone Mapping process. There is a choice of methods within Tone Mapping and I prefer to use the default Details Enhancer. Occasionally it does not work very well. In this example photo the Contrast Enhancer method produces a better result.
There are a number of adjustment sliders in Photomatix Pro that appear to have similar effects on the photo. However, there are subtle differences in the areas of the image they modify, so the best results are achieved when they are used in combination.
Photomatix Pro’s default preset gives a bland rendition of the scene, with all areas evenly exposed. This is gives the scene a slight surreal look, bordering on overdone HDR. This treatment is often used for real estate sales pictures, but the lack of dark areas in a brightly lit scene looks wrong and unreal.
Fortunately, Photomatix Pro remembers your last adjustment settings and applies these as a starting point for the next photo. This makes it easy to apply your own style and look to your photos. If you start experimenting with the settings there are so many possible combinations it is possible to get lost. The easy way to start afresh is to click on the default preset icon to reset the adjustment sliders to their default position. Double clicking on the marker will restore an individual adjustment to its default state.
For a natural looking photos increase the amount of Strength and Detail Contrast adjustments applied to the image, as these increase the contrast and control the degree of shadow in the image.
The Detail Contrast is similar to the Strength adjustment but gives greater control of the amount contrast given to detail in the image. This is similar to the Sharpening tool in conventional photo processing.
On the other hand, I decrease the amount of Tone Compression to help control the contrast and shadow effect. This is Luminosity in older versions of Photomatix Pro. Use it to adjust the brightness in the scene. Tone Compression adjusts the dynamic range of the scene and brightens shadows and darkens highlights.
This is the most obvious example of selective editing based on tonal values. In use it seems unpredictable and hard to control. Moving the slider to the left lightens the darker areas, and also darkens the lighter areas. Lighting Adjustments is powerful and should be used with care as it reinterprets the relationship between dark and light areas.
HDR soft, the people who bring you Photomatix Pro, recommend moving the slider to the right for a more natural look to the image. However, it really depends on the image as I find that sometimes moving the slider to the left gives a better result, and still looks natural. The effect is so unpredictable it is a matter of experimenting with different settings for each image.
Another option is to tick the lighting effect box and choose from one of the boxes. I find the natural + suits my photographic style.
There are more options in the adjustments dialog box.
The Smooth Highlights slider applies a degree of fine adjustment for reducing contrast in the highlights and lightening the skies. It seems to have a greater effect on areas of sky.
Micro smoothing is another adjustment that dampens the highlights, although it affects more of the image than the Smooth Highlights tool.
After HDR processing the image is saved imported into Lightroom and appears in the library view alongside the original. Then I explore the effects of a touch on the Clarity and Vibrancy sliders in Lightroom.
I like this single shot HDR processing technique because it is quick and simple. The original raw photo file is not altered, so it is an opportunity for experimentation without any danger of losing your photo.