Monday, June 30, 2008

High Dynamic Range

Drenched from the evenings down pour of rain

My morning started off with me waking up around 4:30am. It's kind of shocking as my alarm clock wasn't on. I just woke up. It was raining a few hours, maybe minutes earlier. The street was still damp. Since I was up I decided to hike over to the park at the end of the street in my slippers with my tripod slung over my shoulder and my camera in my hand.

Catching the sun rise on the petals

I took a few photos of plant life and the sun started coming up. Shot a few more photos and decided to continue my photography back in the back yard of where I live. The condensation of morning dew on the car looked interesting so I set up the tripod to try to shoot a HDR photo. About half way in Pumpkin jumped up onto the hood. I took a few photos of the cat, waited for him to get bored and leave (I didn't have a pork chop dangling around my neck so I figure the cat would get bored quickly). He did and wandered off to sniff some plant life.

Spikey flora

Pumpkin getting in the way of my HDR shoot

I started from the beginning with my reframed shot of the car in the drive way. The results follow...

High Dynamic Range Photos

HDR, or High Dynamic Range is a method of shooting photos that captures just that, a large range of light going from really dark to really light, more so than your eye can detect without adjustment and what your computer display can show

Take a look at the following photos. The first one is exposed for sunlight bouncing the wall. It's really bright compared to the other things in the photo so if it's properly exposed everything else falls to darkness.

The wall properly exposed.

The sky properly exposed

Now let's say we expose from something less bright like the sky. We see more of the car but the wall starts to go to white, it's becoming over exposed.

The car properly exposed

Next we'll try to shoot the car with the proper exposure. Notice now that the sky and the wall are completely washed out.

The resulting HDR file with the light range squished into visible space.

In the converted HDR image you can now see detail in both the wall and the car. I have taken the light values from the HDR file and squished them into a range that the display (in this case computer monitor) can show.

Shooting HDR photos with a normal camera requires that you shoot a number of photos at different exposures from the same angle and that your subject is not moving. Well the subject can be moving but you might have odd results. The photos are then combined (perhaps in photoshop) and viola, a single HDR file is made.

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