HDR Photography in Photoshop CS3

Though modern day photography allows you to go a long way, adding computerized post processing has opened up avenues that were thought impossible once upon a time. HDR is one of those innovations.

HDR or High Dynamic Range imaging is a technique used to create a balanced exposure throughout the image. So in tricky shots like landscape, where the lighting often makes it impossible to illuminate the complete scene without over or underexposing the picture, HDR allows you to combine a series of variably exposed pictures to illuminate the entire picture evenly, making every shadowy nook and cranny as visible as the brightly lit areas.

A great example of the work done using this technique is the image below showing the New York skyline at night.

New York City at Night by Paulo Barcellos Jr.

Notice how the brightly lit areas don’t appear overexposed, while the shadowy areas too are quite well illuminated. A picture like this would be impossible to take without the help of HDR.

HDR imaging is fast gaining popularity among professional as well as amateur photographers, to the extent that you can find a tremendous community support for it all over the internet. So with this feature, we’ll show you how you can achieve this effect yourself.

Since it’s an advanced technique, slight prior knowledge of Photoshop is required.

What you need
The biggest problem you may face with HDR is that because the whole concept is based primarily on image exposure, a normal digicam will not be good enough for this, as the noise levels in consumer digital cameras tend to appear more on higher exposure settings. Still if you think your camera can pull it off go for it. What I would recommend is a D-SLR.

We used the Nikon D40X for this feature

Practically any D-SLR should do the trick here. I have personally used Nikon D-40X in my example here, and the results were pretty good. So I can safely assume that you don’t necessarily need to go in for a higher-end D-SLR to try out HDR.

The second most important thing for the process is a tripod. Flat surfaces are a good replacement for everyday shots, but when you need to take multiple shots of the exact same scene, you need something a little more reliable. That’s why the tripod is a must for HDR.

Photoshop CS3 is what I have used for this example, as personally I find it easiest to use among the applications I have tried. In case you’re looking for a free application for HDR you can try using Qtpfsgui .

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Getting the right shots
For best results, set your camera to manual mode and take the same shot using different shutter speeds. You can start with a fast shutter speed to get an underexposed shot, then decrease the shutter speed for a perfectly exposed shot and lastly, a slow shutter speed to get an overexposed picture. The following are the 3 pictures I shot for this article.

Under-Exposed

Normal Exposure

Over-Exposed

There are a few things you need to keep in mind while taking these shots:

• Don’t have any people as your subject as getting the exact same shot would be next to impossible with them.
• Don’t take too long in between consecutive shots to minimize chances of your subject changing.
• If you’re not comfortable using manual mode, try using a scene mode and play with the exposure compensation (EV) settings instead.

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The Process
Start Photoshop CS3 and go to File > Automate > Merge to HDR.

Select the images with variable exposures that you clicked in the last step. Make sure that the Automatically Align Images option is selected.

After a short process, you will see a Merge to HDR window showing you the output. I suggest not doing anything here, so just click the Ok button.

The output will be a 32-bit image, so it will come with a 32-bit exposure slider at the bottom of it’s frame in Photoshop. Adjust this slider to get the right level of overall exposure in your image.

The problem is that even after exposure adjustment, the image tends to appear a bit bland or washed out. But don’t worry, we’ll fix that in the next step.

Now the thing is that if you want to make this image usable, you will need to convert it to 8-bit format. In Photoshop go to Image > Mode > 8 Bits/Channel.

You will get an HDR Conversion window with the exposure and Gamma adjustment sliders. Select Local Adjustment in the Method drop down box on the top and click the arrow pointing downwards next to Toning Curve and Histogram to reveal the graph.

Now carefully move the point at the bottom left of the graph to touch the part where the histogram lines start. Then adjust the point on the top right to coincide with the starting point of the histogram on the right side. The graph should look something like the image below.

You will get a preview of what your image looks like at the background as you adjust the points, so you can have a good idea of what the final image will look like. Once done, press Ok.

That’s it, now save the image in any format you want and enjoy your new accomplishment. Go ahead and share it with your friends.