A Cool Photography Trick That Anybody Can Do – HDR

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This post (and, undoubtedly, more to follow) is written for those with an interest in photography, but it might be worth a read for others.

On Sunday at Westfield (more on that tomorrow) I was, as usual, looking for interesting images. In the corner of an old building a classic still life caught my eye. The only lighting came from two windows in the adjacent walls. A flash shot would have captured the image, but it would have been lifeless and flat. This normal automatic exposure taken without flash is interesting, but it certainly doesn’t have much to say: (as usual, you can click on any image for a larger view – the effect will be more evident)

A normal exposure.

All of the subtle textures that you can see with the eye are lost in the darkness of the underexposed regions in the corner and other shadow areas. The human eye has a huge ability to extract details from an enormous range of lighting (a large dynamic range). Digital cameras have varying dynamic ranges, but none can match the eye; none that I can afford, anyway.

A trick that we can use, given a computer and software, is to take three or more images with different settings of the camera and glom them together. I use Photoshop, but several other programs can do the same thing.

First, we take three or more images with different camera settings – one or more underexposed (too little light gets in), one normal (just right according to the camera), and one or more overexposed (too much light got into the camera). Many cameras can do this for you automatically. Look for auto bracketing in your owner’s manual.

Next, we can use the computer to merge them into one image that combines all of the best exposed parts and shows details that would have been lost in any single exposure. It works not only for the dark areas, but also the bright areas that might be ‘blown out’ (turned white) in a normal exposure. Here is an image that combines three images into one using this method: 

An HDR version usnig three exposures.

As you can see, the details in the dark corner and shadows are now visible. The photo takes on an almost painted look. I think it looks like this because it’s an image that more closely matches what the eyes see – as a painter records what he sees with his eyes.

This is called High Dynamic Range photography. You can see some amazing examples in the Flickr HDR Pool and in The Hive Mind. You can also see that it can be carried to artistic extremes.

I should mention that HDR is better accomplished if you can keep the camera absolutely still. A tripod is perfect, but you can usually find a way to brace well enough. I was shooting from the middle of the room and the image is suffering a little from motion blur due to the slow shutter speed. Also note that nothing in the composition can be moving – you’ll just get several ghostly images (one for each exposure) if anything moves.

If you want to take it one step farther, you can use one of many ‘artistic’ filters available in Photoshop and other programs to enhance the artsy effect. Here’s the same image with the Watercolour filter applied: 

HDR image with the watercolour filter applied.

This is the kind of thing that anybody can do. I love photography today more than ever. I can do amazing things with virtually no equipment (an average pocket digital can take the exposures), free software (such as GIMP for PCs and MACs) and a few minutes of figuring it out. Most of these things were impossible only twenty years ago.

Life just keeps getting better and better.

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