When it comes to digital camera abilities, I am often not completely satisfied with the out of camera image, especially when it comes to very contrasty, landscape scenes. The small sensors, still in their infancy of development, can’t always cope with the complexities of the scenes they are dealing with. The range of light and colour that it can capture, known as ‘dynamic range’, is much limited compared to film. This is especially so with the Jpeg image that you finally use for printing or putting on the internet. Yet many digital cameras also allow you to capture in the form of ‘Raw files’, with a lot more data in them. Many people refrain from this, as the file sizes are bigger and since you have to make a Jpeg anyway, they end up being more trouble. Yet this Raw file contains a lot more usable data if you are going to post-process the image, altering it on a computer.
If you ‘bracket’ the capture of these Raw files- by taking various shots quickly on the tripod, getting them at lower and higher levels of exposure as well as the ‘correct’ version, you capture even more usable data. Many DSLR cameras actually have automatic settings for this and I often take hundreds of shots in total this was, with not all that many subjects (my record is 9 shots to blend, which gives me the smoothest results. With enough data, you end up with as much, or even more than the human eye can see. So what to do with it all?
Hollywood had a need for ‘High Dynamic Range ‘ imagery, to alter when producing special effects. I suppose one reason was so that the same digital creation could be manipulated to fade in and out, or to show it at different times of day, without constructing it from scratch. This technique soon made its way into digital photography, using methods like mine to capture the initial images, then blending them on a computer. This creates a ‘HDR’ image, or tremendous dynamic range- at 32bit (possessing billions of colours and light levels). It can be kept as an EXR image, a format developed by Industrial Light and Magic (Lucusfilm). But it cannot be displayed as is on today’s monitors, which are only 8-bit, let alone seen on the Internet or printed. So we reduce the dynamic range, though keeping the ‘localised contrast’- the benefits of having all that information being represented in a form with less extreme contrasts. The range is compressed, if you will. It is a bit like the way music is digitised onto CDs or, more recently, into MP3’s. We can sense the richness of it, without in fact having the full range of sounds involved, which would take too much space and be impossible to play back anyway. So you feel like you are seeing a tremendous range of light and colour, whereas actually it is being seen on just the usual, limited monitor or paper ‘ordinary’ images are seen on.
I use what is probably the most popular software for this- Photomatix Pro. I’ve been using it for years and it is currently on version 4.0. It gives very pleasant results and is easily adjusted with a range of sliders. I am very careful how I use it, as it is easy to create results that appear overblown, lacking contrast and being very garish. In fact, a common problem with HDRs is just that, as people try to show a great range in the form of the image, leading to wild and extreme colours that look nothing like the real world.
I believe in going a little beyond what our eyes can see naturally, but not too far into the realm of fantasy, as at that point the image is unbelievable. A photo should stun and move people, but to do so it needs to be believed. It doesn’t, in my view, have to be anything like what you actually saw at the time, as the atmospheric conditions and weather could well hamper your appreciation of a scene. Yet if it is wonderful, yet believable, people will enjoy seeing it. Other HDR/tonemapping creators actually like the psychedelic effect of extreme colours and so on. Ultimately, there is no right or wrong answer, it comes down to taste and for me, the ‘true-tone’ HDR images look best.
To me, HDR imagery is to photography what digital effects are to cinematography. Used well and artfully, they can create an incredible, yet convincing world. Purists will say they have no place, yet the pleasure people can get from viewing them is, for me, justification in itself. It also solves a central problem of digital sensors, their low dynamic range compared to slide film and makes them capable of just about anything.