HDR Part I

boats-and-godbeamswebAfter seeing Trey Ratcliff’s work on http://stuckincustoms.com, I’ve become a firm believer of the HDR process.

For those that aren’t familiar with the term HDR stands for “High Dynamic Range.” Dynamic range is critical in a photograph because its essentially the range of light you are capable of capturing and presenting in an image. Your eye can see 20 plus “stops” of light, whereas your DSLR (even a D3!) captures about 5 stops of light. That’s an incredible difference in light value.

Practically speaking what does this mean? Well, take a picture on a bright sunny day, maybe of your kids baseball game. What happens? Highlights get blown out and shadow areas lose all detail – like faces under a batting helmet become ‘black holes’ in the image.

As a photographer you have to make a “choice”~ expose for the highlights, or expose for the shadows… decisions, decisions, decisions. Typically people expose for the highlights because they don’t want their image be “blown out” (meaning all white in an area, no subtle detail apparent). HDR technology allows you to capture a range of light greater than the normal 5 stops. Allowing you to re-introduce detail in your shadow and highlight areas, and better catch the “feeling of being there.”

The image at left is an HDR image of a sunrise over Wanchese harbor in the Outerbanks. Beautiful Godbeams cracking through the clouds, and dark shadows in the buildings and in the reeds make this a scene of great contrast and emotion. A single shot would absolutely have blown out the Godbeams, the Sun and would have left no detail by the shoreline and buildings- the camera would have struggled the best it could to “even” out this scene, but it would have failed…

So took 5 images at 1 EV apart. EV is exposure compensation and is usually a little button on your camera with a “+/-“ on it. This allows you to dial in more or less light based on your aperature setting. So “bracketing” shots at 1 EV apart I end up with 0 exposure, +1 exposure, +2 exposure, -1 exposure and -2 exposure. Bracketing is done in camera and is literally 2 clicks to set up on a D3 or on a Canon 40D.

Make sure your camera is stable – a TRIPOD is a must for these types of shots as you will be using software to blend them together later on. Any shake, any vibration, anything that moves the images during the bracketing sequence will result in ‘softness’ in the image, which sucks. You go through all this work and in the end find out that it’s a tinsy-weensie bit off- image won’t work. It’s happened to me… which is why I encourage you to use a sturdy tripod (Gitzo), a sturdy ballhead (Really right Stuff) and an “L” bracket for switching your camera quickly between vertical and horitontal shooting.

Now, that’s not to say you can’t handhold or use a lesser piece of equipment, just REALIZE, you increase the probability significantly that something will shake, rattle or roll, and that will influence your final capture.

Part II… later. 🙂 

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