HDR Tutorial
The software I use for all my HDR work is Photomatix Pro by HDRsoft. If you’ve come here looking for my 15% off discount code for photomatix, it’s DanNorcott, and you type it into the ‘Coupon code’ box of the order page, which can be found here (click ‘purchase’ at the top, then choose the version of the HDR software you want). Make sure you click “recalculate”, and you should see the discount appear. A free trial is also available.
HDR (High Dynamic Range) photography is gobsmacking when you first see it done well – but the lack of simple tutorials meant it took me a long time to really understand how it was done. This is my attempt to help other people in that situation by creating my own HDR tutorial.
The main purpose of HDR photography is to show a higher range of detail than could be possible from a single image. When the human eye scans a scene, the pupil dilates and contracts, enabling us to quickly flit around the image and perceive detail in all but the brightest and dimmest conditions. When taking a photograph, the camera (or the operator, if it’s in manual mode) has to decide what length of exposure to use in order that the important parts of the picture retain detail.
When using raw mode on a DSLR, the image can be pushed about a stop of light* either way (brighter or darker) without significantly affecting the image quality – which, whilst better than you would get from a JPEG, is not enough under most conditions to allow detail throughout the scene.
* This terminology can be confusing. “A stop” is basically twice or half the amount of light hitting the sensor. So, if you had a properly exposed image, then an extra stop of light is twice as bright, and one stop less is half as bright. Stops aren’t to be confused with “clicks” on the little wheel you rotate – that can normally be adjusted in the camera’s functions to go 1/2 or 1/3 of a stop each time. You can adjust the amount of light hitting the sensor by either changing the aperture size or the exposure length – for HDR, you must only change the exposure length between shots, as changing the aperture size will affect the depth of field of the image and stop the images stacking up correctly.
A SAMPLE IMAGE
If that had been taken from a single exposure, I couldn’t have packed that much detail in (without a lot of filters and post processed jiggery pokery, at the very least).
Obtaining the image
You can take as many as you want – I normally use Auto Exposure Bracketing – a setting your DSLR probably has, which enables you to take three pictures in quick succession (I have it on multi-shot mode, so I can just hold down the button and it takes all three) at a set range of exposure times. The 450d (and 350d/400d) allows you to go up to two stops either way. This is a bit of a shortcut – the longer way to do things is to adjust the exposure time manually, and take as many pictures as is necessary to ensure you have one with no blown highlights, and one with no blown shadows – how far you go is up to you, and the effect you want to achieve – the only stipulation is that the pictures must be even steps apart (eg. 1 stop, 2 stops etc).
*NOTE – I’VE RECENTLY LEARNED THAT THIS ISN’T TRUE. THE IMAGES DON’T HAVE TO BE EVEN STEPS APART. SO YOU CAN WING IT A LITTLE 
Also, whilst you can make HDRs with JPEGS, I would suggest there’s little point. I got into the habit of always using raw a while ago – it makes for better HDRs, and gives you more control over your final images.
For the image above, I used auto exposure bracketing, and I didn’t have my tripod with me, so I set the aperture to f/11, and the iso to 200. Normally for a landscape shot – especially a HDR – I would go for iso 100, f/22 and a tripod – but sometimes you find yourself in front of a nice picture in the right light and just have to make do.
Also, I’ve found when I’m going out with other humans it’s much better to not take along a tripod and pile of kit unless they are camera geeks too. It’s a tragic sight to see an excited photographer setting up all his gear next to a babbling stream, as a wife and family look on, bored to tears by the whole thing. Save that for when you’re out on your own, and try chancing a hand-held or two!
Then I leant on a sign to give myself some extra stability, and fired off three images:
1) Normal image:
2) Two stops below :
3) Two stops above:
Here are the three original raw files from my Canon 450d that I used to create the above (you might want to right click + save as, or ctrl+click/save target as for macs). You could use them along with the free demo of photomatix to have a play around.
056.CR2 (normal image) – 21MB
057.CR2 (-2 stops) 17MB
058.CR2 (+2 stops) 22MB
autumn.zip – a zip file of all three – 57MB
Now on to page two – creating your HDR