Digital Thoughts: Bracketing

Of course you could call it a way of dealing with possible mistakes, and find HDR is a bonus …


Bracketing can be a safety net.
The bracketing feature has been in digital cameras from the earliest models I looked at, but later models have more options. When you buy a camera check to see if you have the option of bracketing not just ISO but other things like the white balance or perhaps the focus point.

When you fire a burst of frames there may be a variety of purposes.
An obvious one is HDR; vary the ISO to get the foreground and the skyline and then use the post-processing to combine them.

But you can also fire the bracketing using an intervalometer; get varying HDR exposures thorough the day.

Of course the bracketing might be a case of ‘you are not sure what is the best setting’ and have the camera take a variety around the point you choose.

There are tricks you can play by ‘just bracketing’.
One is removing traffic and people from a scene.
Over a number of exposures the people, the traffic won’t be in the same place and the HDR techniques of post-processing of multiple overlays will combine the static parts, the background image, and fade out the ‘traffic’. The more exposure you have to work with, the better.

A variation on the HDR technique by bracketing the exposure can be used to magnify the dynamic range of a scene. Well isn’t that, sort-of, what HDR is about? Yes and no. Most people use HDR to magnify the colours, often producing something weird-looking rather than simply the Dynamic Range, bring out the shadow and clarify the highlighted areas.

Then there’s using multiple, near identical images, blended for noise reduction.

One thing I haven’t tried is bracketing with varying light angles. It occurs to me that this is not just for good images of object for sale on eBay but also for some interesting portraits. Gunda has a couple of excellent portraits of me under full sunlight, but I wonder what they might have looked like with bracketed shots using a reflector?

Then you can play with bracketing while altering focus, giving a much greater depth of field.
One of the problems with macro photography is that many of the lenses give a DoF that is wafer thin. OUCH! So, once again, merge a bracketed sequence where the focus point is varied. You can get ‘infinite DoF’ Well it is not as simple as it sounds; changing the focus on a macro lens also affect scaling… you need good merging software for this. And probably a LOT of microscopic alternation step-and-repeat images.. However the result needs no specific retouching.

Finally I want to mention using bracketing for making movies. Think of movies like Wallace & Grommit


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