Wednesday, September 26, 2007

HDR-Art or Artifice?

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St Severin, Paris

High Dynamic Range photography, where several images of the same scene are taken and then merged using software to capture the extremes of the tonal range, seems to be gathering momentum. It's been around for a while now but there are groups springing up all over the place with examples of this technique. Everyone knows the difficulties photographers face when they try to record the lightest highlights and densest shadows on film or digital. Ansel Adams pioneered the use of the zone system to overcome this problem. In comparison with digital photographers, old Ansel had it easy. The exposure latitude of digital is much smaller than that of film and, therefore, it can be even more difficult to capture all the tones unless special measures are taken.


Hampton Green, Arbroath

Many of us have tried blending two exposures in Photoshop, one biased towards the highlights and the other the shadows, with varying degrees of success in my own case. HDR takes this a step further. It's best to have the camera on a tripod as the images have to be in perfect register to ensure sharpest results. The greater the range of tones in the scene, the more exposures should be taken. Three are OK but sometimes five-even more-are better. The bracketing should span at least two stops above and below the "normal" exposure and it's best to leave the aperture alone and adjust the shutter speed. The darkest file should look almost black and the lightest almost white. It's possible, I believe, to blend these together in Photoshop CS3 but I only have CS and I've consequently never tried it. Instead, I used Photomatix which does the job very quickly and easily.



Cafe Marmaris, Arbroath


Two things have to be done with the bracketed exposures. First, these have to be loaded into the software so that an HDR file can be generated. Then the resultant file has to be "tone mapped" which is a way of simulating the appearance of a high dynamic range on computer monitors that are just not capable of displaying true HDR. Tone mapping sort of squeezes the HDR file to match the contrast range of the average monitor. The effect, depending on the various settings used for tone mapping, can range from the quite natural to the Disneyesque.



The Boatyard Cafe, Arbroath Harbour

If we can forget for one moment that these images started off as "photographs" and just consider them as art, then I like them a lot. They have a charm about them and a cartoony quality that appeals to me. Printed on nice paper and framed, they'd look good hanging on the wall. In some cases, I definitely prefer them to photographs of the same scene. Interior shots with bright light streaming in through the windows look great.

The biggest drawback in my admittedly limited experience is the unpredictability of the process. Sometimes I'm certain that the scene in front of me will look stunning in HDR only to be disappointed at how dull it emerges from Photomatix. At other times, I've taken photographs of quite ordinary subjects just to see how they will look and been very pleasantly surprised. However, the seemingly arbitrary nature of HDR is also one of its plus-points as you never know what you're going to end up with. I'm finding HDR quite interesting and will be doing some experimentation in the weeks ahead. I want to change the white balance of the files and also might work on their contrast before they're merged into an HDR file for tone mapping.

The shots in this post were all taken with the K10D and the 16-45mm zoom. Since the camera was on a tripod, I used 100 ISO as there wasn't a lot to be gained from anything faster. I think I've written before that the 16-45 lens is a cracker and it gets even better when the camera is tripod-mounted. There's a little bit of distortion that's correctable with software but sharpness, contrast and flare resistance are of a high order. I really can't see any difference between the results I get from the zoom and those from the 21mm DA prime. Maybe if I peered really hard at the two files I'd notice something superior about the 21mm but let's just say that it isn't apparent in everyday shooting.


Now, with my photographer's hat back on, I have to say that I partly agree with critics who say that an HDR image isn't a "real" photograph: it's more like a photography-based graphic image. It might also turn out to be little more than a gimmick. In a year's time, we might all be looking back at HDR the same way we now view all those Cokin filtered and black and white infrared shots that once looked quite innovative. Or even worse, the way we now look at the flares, kipper ties and butterfly collars of the 1970s...

8 comments:

  1. Bruce, I've experimented with Photomatix myself and enjoy using it on selective basis.

    I prefer to be selective with it because I don't want to be a photographer who succumbs to the gimmick factor by turning every kind of shot into an HDR, especially when the shots in question are patently inappropriate for HDR conversion in the first place.

    Instead, I like to use Photomatix to generate lower-key, realistic renderings, which I find can be produced quite easily, with care.

    I reckon if I create HDRs that are not overtly HDR-like, I've done my job properly.

    Regards,

    DW

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  2. Along the same lines as the previous comment...

    HDR is a useful technique for overcoming the limited dynamic range of digital sensors, but it seems that few photographers are able to produce HDR images with any sensitivity. The shots that scream "HDR!" at the user are so common that they've become a bad cliché.

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  3. I see where you're both coming from but I think it's unfair to say that "few photographers are able to produce HDR images with any sensitivity". It's very easy to limit the HDR effect so that the scene looks natural but it's a fact that some photographers just happen to like the HDR look and deliberately go for it. That's not showing a lack of sensitivity: it's just their preference.

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  4. Bruce,

    I absolutely love the effect. An image is an image is an image. Manipulation a new toolof our time that allows us, photographers, to modify images just like a painter does. We paint with light instead of oil paint. For those that are against any manipulation, go back to film media. Better yet, go back to large format camera. Note that Ansel Adams always manipulated his negatives in his studio, with the tools available in his time, i.e. burning, dodging, the whole zone system!

    If it looks good, it must be good. It's all in the eyes of the beholder.
    Regards,

    Yvon Bourque

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  5. Bruce,

    Some great images here. I agree- Ansel Adams would have been fascinated with it! Although I think I prefer when the effect is subtle.

    cheers,

    Dave.

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  6. For those that are against any manipulation, go back to film media. Better yet, go back to large format camera...

    All art is a manipulation, and always has been. No problems there.

    But that wasn't the point I was making. I was simply saying that HDR has become a cliché because it is frequently overdone -- the technique itself often clumsily overshadows the subject matter.

    The same thing happens every time a new technique or tool appears -- it gets done to death for a while.

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  7. Funny, I thought HDR was so last year, and photographers were already moving away. I agree that all art is subjective, so speaking personally, I must say that this technique has often been used to compress images into a repulsively plastic caricature of what the eyes see. Personally I prefer a good bit of contrast.

    But I'm not against it per se. I have seen it used quite effectively and so I agree with DW and anonymous above in applauding a light touch when employing it.

    Damon

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  8. Come on, Damon! Saying something is "so last year" is so last century! ;-)

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