What is HDR Photography?
High Dynamic Range Photography is the process of taking several pictures of the scene and changing the exposure setting in your camera for each picture. Once the images are taken (hopefully RAW files) the images are downloaded to your computer. With HDR software, the images are analyzed pixel by pixel. The software takes the best pixels of each image and outputs a single file with all the best pixels. Of course there is lots going on behind the scenes but that’s the general idea in lay terms.
Taking an Image Set
The first image should be what your camera thinks is the best overall exposure for the scene. That’s called the 0 exposure value or 0EV for short and is shown here. Notice there is a wedge of color missing in the sky (blown pixels) AND the rocks in the foreground have no detail.
The dynamic range of the scene exceeds the dynamic range of my camera sensor.
The next image I take is over exposed – you know the one’s that look all washed out. It’s taken in the same position as the 0EV image, but it’s 2-stops over exposed or +2EV.
The over exposed picture captures shadow details in the area of the rocks.
My last picture is taken at -2EV or 2 stops under exposed. This exposure captures details in the sky that the other two pictures lack. Notice the wedge of brightness in the sky is now saturated with color.
The under exposed picture captures highlight details in the sky.
We just took 3 images @ 2EV spacing. Add that to your everday conversation with photographers. It is the undisputed workhorse of HDR photography. It will provide sufficient dynamic range for most scenes and can be easily done with most cameras.
**The high end Nikons and the new Fuji S5 Pros are set up to shoot 1EV spacing. That means each image set will be 5 images @ 1EV spacing. You can omit the +1EV and the -1EV if you like.
Here is the final image after merging to HDR in Photomatix Pro software.
I never knew my camera could change exposure settings?
Most cameras, even point and shoot’s, have a feature called exposure compensation that allows you to dial or toggle in a new exposure.
Can I take my shots in JPEG mode?
HDR photography can be done in RAW mode or JPEG mode. Shoot in RAW mode if your camera has it, you can sqeeze out a little more dynamic range. The father of HDR, Greg Ward, conceived, designed, wrote, and tested HDR using JPEG images.
Can I do this handheld or do I need a tripod?
HDR photography can be done handheld, however just as in all photography, using a tripod will improve quality. Photomatix Pro is able to align the images but don’t get to relaxed about it. It can’t correct for a sloppy shooting style. Here are a few points:
The camera must have Auto Exposure Bracketing. First you dial in Auto Exposure Bracketing (AEB), compose, then press the shutter release button to take the images. No fumbling with the camera between exposures.
Always scope out a steady object to lean the camera on. If it’s a pole just press the edge of the camera against it.
If you must shoot free-standing then concentrate on being steady during the entire image sequence. Lock your eyes on the brackets in the viewfinder and “register” it with a spot in the scene.
Ok, now you have a bunch of pictures that you’ve downloaded and it’s time to create some HDR images.
You can stop by and see my Photomatix Tutorial in this blog.
You can also download a free trial version of Photomatix from www.hdrsoft.com
Get 15% off the Photomatix program (reg. $99) just by entering “beforethecoffee” in the coupon code box of the Photomatix purchase page.