High Dynamic Range
High Dynamic Range or HDR photography is a new technique for most people.
HDR photography involves taking multiple exposures of the same scene and then letting software blend them together to produce an image that is correctly exposed across each pixel of the final image.
A series of standard images are merged into a single 32-bit image which has a dynamic range up to 15 stops. This is then converted back into a 16bit image for display or print.
The most common uses of HDR is when the right exposure for a scene results in washed out areas and a flat looking image. By creating a tone mapped HDR image you get the sky details and the correctly exposed image together in the same picture.
How do you create an HDR photo?
The simple answer is that you need software to do it for you. Currently your options are to buy photomatix or a similar tool, or download the free , open source tool called "qtpfsgui" which is a dreadful name for an excellent bit of kit.
Here is the first HDR photo I ever created
It is made up of 7 separate shots taken on a grey wet january morning (shown right) merged using qtpfsgui. Itook a series of exposures (+3,+2,+1,0,-1,-2,-3) none of which individually produced a balanced image in the poor light.
The camera was on a tripod and all exposures were taken with the same aperture 5.1 and low iso (100). The only thing that changed for each eposure was time. The shortest was 1/320 while the longest was 1/5 of a second.
Not a good composition (look, I even chopped the top of the weathervane off!) but the dynamic range is stunning in comparison with most shots taken in january.
Of course, as with all things you can overdo it, but sometimes the 'hyperreal' effect itself becomes pleasing.