Bracketing, HDR and Kids Oh My!

Bracketing is:

1. punctuation you use in your blog to enclose words and separate them from the context [my kids are trying to drive me insane]
2. a categorization method to group good kids from naughty ones
3. a photography term used to indicate the capturing of multiple photographs of the same scene, taken with different exposures

While all of the above may apply to you, it's the latter that we'll talk about today. Each camera has a dynamic range more limited than the human eye. So the camera is unable to capture all the details of a high contrast scene. Sometimes that means that the shadows will be too dark (e.g. the facial features of an individual are indistinguishable against the backlight of a window) or that the highlights will be clipped (e.g. the sky looks white instead of blue). One way around this is to take multiple photos and combine them into a single high dynamic range, or HDR, photo. It's like your toddler cramming pee and poop in a diaper giving it more umph!!!

So how do you make an HDR photo? You can either set the exposure manually for each of the three shots or most dSLRs have an automatic bracketing feature (check your manual). Take a photograph metered by the camera (f 5.6, 1/500 sec, ISO 100). Notice how the sky is clipped, or totally white in the top right corner.

Take another photograph two stops darker (f 5.6, 1/2000 sec, ISO 100) and the sky is well exposed, but much of what's on the ground is on the dark side, particularly in the shade.

...and technically, the final image could have been done with two exposures, but an extra one never hurts. And that's the beauty of bracketing - it's a way to be sure that you got the photograph you intended. I didn't know till I reviewed my handiwork on the trusty Mac Pro, that the first two would have been sufficient, but the third was literally just another click of the button and captures an exposure 2 stops over the first picture (f 5.6, 1/125 sec, ISO 100).

It's best to take the series of photos using a tripod so that everything is aligned but both Photoshop and Photomatrix can also reasonably do this if the images are a bit off. This particular series was taken hand held and then processed in Photomatix which helps merge the photo, creates an HDR image and allows you to tweak the strength, amount of smoothing, gamma, micro contrast and a bunch of other fun stuff to create the final dramatic photograph. Next week, we'll talk about how bracketing can be helpful even when you don't intend to create an HDR image.

...and in case you think this has no practical application in children's photography, think again. The very first picture on my website was made with this technique. Your kid doesn't even need to stay still for the image which is the other thought going through your head, but we'll talk about that some other time.

Final Note: The astute observer will notice some minor changes to the blog site such as the twitter feed off to the right. Personally, there's little need to fill life with any more interruptions but I thought I'd give it a spin because, well, I need your support. The wife is going to take her board exams and is gone the next three days. Anyone who wants to see the play by play on how I simultaneously take care of the kids, do my day job, make dinner, put the kids to sleep, lose my sanity and work with a wedding client this weekend can visit this blog, click on "follow my tweets' on the right or view them at twitter. BTW: Anyone have any thoughts on whether it's a good idea to bring the kids along for the wedding rehearsal? Wish me luck.