HDR

On yesterdays post, Maureen asked what I used to edit my photos, so here is my (probably longer than required) answer.

A lot of my landscape photographs use a technique called High Dynamic Range (HDR) imaging. A HDR image, as it’s name implies attempts to represent a wider dynamic range, or greater range between the lightest and darkest areas of the photograph. This allows the scene to appear more like it appears to the human eye than a standard photograph.

In photography, dynamic range is measured in “stops”, the photographers unit of exposure value (EV). An increase of one EV (or “stop”) equates to the amount of light coming through the lens doubling. The human eye is thought to be capable of processing a dynamic range of up to 14 “stops”, but a standard camera can only handle 9 or 10. So when you have more dynamic range in your scene than your camera can handle you will generally get some areas of the photo that are too dark, or some that look washed out.

The HDR technique involves taking multiple versions or “exposures” of your shot, one that is correctly exposed and others that are darker (under exposed) or lighter (over exposed). I usually take three shots, one at normal exposure and one at two stops darker (EV -2) and one at two stops lighter (EV +2). This is referred to as “exposure bracketing”. Most DSLRs have an “automatic exposure bracketing” (AEB) feature that allows you to have them take the multiple exposures automatically.

Obviously you want your multiple exposures to be the same “scene” so holding the camera steady is essential, using a tripod is highly recommended especially as the lighter exposures will often want to hold the shutter open for a longer time than you can normally hand-hold the camera for successfully. Also, ideally you don’t want a lot of movement in your scene between the multiple images.

Then, a HDR software package is used to merge the multiple exposures together. I use a product called Photomatix Pro, which is fairly inexpensive (under $100). It offers lots of different processing options and “presets”, but I normally try for a fairly natural effect, although I do like to fiddle a little bit and like some of the “painterly” effects that can make your image look somewhat like a painting.
I also use Photoshop Elements but am only a novice user, pretty much sticking to basic cropping and things like that.

Some photographers do think that HDR is “cheating”, but I enjoy it, and honestly think you can produce an image that looks a lot more like the image you saw with your eyes than is usually possibly straight out of the camera when you have a “high dynamic range” scene to capture. That said though, I do prefer it when photographers own up to using techniques like this, or in fact any post-processing. If you look at my photographs in Flickr you will always see a comment like “three exposure merge” for my HDR images. Also, because I always put the camera image numbers in the photo title it will show multiple images (e.g. _MG_3834_5_6) for those that use multiple exposures.

Anyway, hope that answered your questions Maureen, and here are a few of my favourite HDR images.

Melbourne GPO Columns 2012-03-03 (_MG_3871_2_3_4_5_6)
Melbourne GPO Columns

Hosier Lane Panorama 2012-03-03 (_MG_3904_5_6_7_8_9)
Hosier Lane Street Art

The Nook 2012-03-11 (_MG_4364_5_6)
The Nook, Goonawarra

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2 Responses to “HDR”

  1. Ewen Says:

    It’s an interesting technique Andrew. Agree the photographer should own up to how it was done. The HDR images have a similar look to them. Can’t say I like them more or less than ‘normal’ images.

    Saw another technique today which makes a scene look like a model using ’tilt-shift’ lens or processing:
    http://www.jamesallenonf1.com/2012/05/jenson-button-sets-the-pace-on-frustrating-first-day-in-monaco/

    • Andrew(AJH) Says:

      Yeah, I’ve seen that before too, haven’t worked out how to do it though. I enjoy mucking around with the HDR, but there is nothing better than a great “straight from the camera” image. I don’t think there are too many of them these days though, there are a lot of photos out there where there is no “owning up” to the post-processing too.

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