Photography News issue 23

Technique 61

Photography News Issue 23 absolutephoto.com

Photo school Camera class Everyone has to start somewhere, even pros, and in Photo School we look at the core skills every beginner needs. This month, how to shoot and process High Dynamic Range pictures in camera and in Adobe Lightroom

Step by step How to shoot HDR

Words & pictures by Kingsley Singleton

Because a camera’s sensor responds to light differently to your eye, it’s not always capable of recording the world how you see it, most noticeably when shooting a scene with very bright parts and very dark ones. These highlights and shadows look normal to you, but in the picture, detail is lost in one or the other area, so you just get pure black or pure white pixels. The answer? Well, one method is to make a High Dynamic Range (HDR) picture – one that reproduces a greater level of highlight or shadow detail than possible in a regular exposure.

The best way to create HDR pics is to shoot different exposures and combine them in software, but on some models you can also do it all in camera, which is good for quickness. Whichever route you use, multiple exposures of the same scene need to be produced, then merged (either by you or the camera), some of which record detail in the highlights and some in the shadows. HDR from Raw? Alternatively, due to the extra information contained in Raw files, just one shot in that format can

contain all you need to make an HDR image; you just need to convert the Raw file once for the highlight detail and once for shadow detail, saving those versions of the picture as separate files. Next, combine them using an HDR package like HDRSoft’s Photomatix Pro 5, as described right, or blend them manually using Photoshop layers. Going HDR from a single Raw file is great for scenes with moving subjects, like flowing water or crowds of people. On the downside, if you lighten or darken the Raw too much you can lose quality.

1. Lock position, aperture and focus The camera should be on a tripod so there’s no movement between the frames. The depth-of-field and point of focus should also be consistent, so shoot in aperture-priority mode (A or Av), focus on one part of the scene, then switch to manual. Set ISO manually, too, so that when the bracketed exposures are created it’s only shutter speed that changes.

2. Bracket the shots Activate the camera’s bracketing mode and choose the number of shots. This depends on the scene’s dynamic range, the exposure difference between each shot and what your camera offers. So, while three shots at +/-1.0EV would cover one scene, a contrastier scene will need more – like five or seven shots. Switch to self-timer, and shoot until all the exposures are recorded.

Before

After

3. Merge the exposures Load the light and dark exposures into your HDR software (here we’re using Photomatix Pro 5), and within the main interface you can choose how the exposures will be combined – a process called tone-mapping. Very different results can be produced, from photorealistic to gaudy via presets, which can be adapted using sliders to control brightness in the highlights, midtones and shadows.

Making HDR files is a new feature for Lightroom, and is found with the Photo Merge options. It works very well, giving a more photorealistic look than a lot of stand-alone packages, without the emphasis on lots of micro-contrast. And what you get after merging multiple JPEGs or Raw files is a much larger file with a lot more exposure latitude within in. This behaves just like a regular Raw file, just one in which you can make a greater level of adjustments to settings like the Exposure (on a regular Raw file, the Exposure slider runs from +/-5 stops, but on an HDR Raw it’s +/-10 stops. Very few Develop settings, like Exposure or Highlights, that are applied to a file will be carried over to the new HDR DNG file when the process is complete, so any creative editing, also including using the Graduated filter tool, should be saved for after the HDR process. Here’s how it’s done... Software skills Photo Merge HDR in Lightroom

1. Select the pictures In the Library module, or via the filmstrip at the bottom of the interface, highlight the files that you want to use, then either Ctrl- click or right-click on them and go to Photo Merge>HDR (you can also find this option under the Photo menu). The more files you add the higher the quality, but the slower the process, so try sticking to around five shots.

2. Control the blending In the dialogue box that appears are options to Auto Align handheld pictures (deselect if you shot on a tripod) and Auto Tone, which applies exposure changes (this is undoable later). The Deghost Amount sets the level of correction for moving parts of the scene, like trees or water, depending on the amount. You can also tap O to show areas being corrected.

3. Final editing Hit Merge and after a few moments a DNG file will be created with the suffix ‘-HDR’ (making it easy to search for). This file can be processed like any other, but is much larger in terms of file size, as it contains more data. To heighten the HDR ‘look’, try moving the Highlights and Whites left while pushing Shadows and Blacks right. Finally, add some Clarity.