HDR : a series of photographs of the same scene (commonly referred to as a ‘bracketed set’), only each photograph differs in exposure.
A bracketed set is made up of either 3, 5, 7 or 9 photographs. Each set should contain very dark photos through to very bright photos (see image 1, opposite). We then take our bracketed set of photographs and merge them together in specialist software.
The very dark photos reveal details in the bright areas, such as clouds, and the very bright photos reveal details in the dark areas, such as the shadows.
What follows now is a very basic and almost an automatic technique. This will get you started and you can advance your technique and as and when you're more comfortable with it all.
Let's start by switching your camera to Manual Mode (M). Our bracketed set of photographs need to be taken with different 'EVs' - Exposure Values. Looking into a camera's viewfinder (or a rear screen), you should see an exposure scale along with a needle or marker. Depending which way you set your exposure, should the needle travel along the scale to the left, then the photograph will be dark, or to the right, the photograph will be bright.
Along the length of the scale you should also see numbers: '0' (zero) being in the middle, and 1, 2, 3 (and sometimes 4) spreading out equally left and right. Left
being the (-) minus value right the (+) plus value. We'll call these numbered separations 'stops'.
The rule of thumb with 'real' HDR means it requires a '0' photo, and to complement it, it also needs - (minus) and + (plus) photos. Looking at the EV scale, the numbers you should concentrate on are 1 and 2 (see the settings below). Now we need to look at your camera's AEB function and decide which you should select. Here are the standard settings (illustrated in graphic form opposite):
2) 3 photos at 2EV, 3) 5 photos at 2EV, 4) 7 photos at 1EV and 5) 9 photos at 1EV.
You see? For a 2 EV setting, there are markers every 2 full stops on the EV scale, and for every 1 EV setting, there is a marker at every full stop. If you're a beginner, I suggest that you start by setting your camera (in Manual Mode) to take 3 photos at 2EV. The more confident you become with the software, and the more photos you merge, then the better your results.
3) 5 photographs taken at a spacing of 2 EV.
2) 3 photographs taken at a spacing of 2 EV.
4) 7 photographs taken at a spacing of 1 EV.
Once you're comfortable with the process, then you can advance to taking your initial readings in AV mode (Aperture Priority) and start using the
5) 9 photographs taken at a spacing of 1 EV.
1) This is an illustration of a set of 7 bracketed photos taken at a spacing of +/- 1 EV (see 4 below), followed by the '0' (zero) photo and then the final blended HDR.
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