HDR (High Dynamic Range) photography is a process that has existed for a long time, but has come into prominence in the past few years thanks to advancements in software and camera technology. In a nutshell, HDR takes two or more exposures of an identical shot and averages the values out to create an evenly exposed image with no glaring shadows or highlights.
HDR can be also be employed to make hyper-realistic, even, surreal images. Try googling HDR photo and you’ll see some pretty trippy stuff, but the main directive of this post is offer an explanation and tips on how to make a better natural looking photograph.
The human eye detects and processes light selectively and more powerfully than a camera can capture. One might be looking at wide scene with a range of shadow values, but most times we can focus on a shady area and see a lot of detail that a camera would emit. Similarly, on a sunny day, the sky never looks white, but we’re all familiar with “blown out” skies in photographs.
Often when shooting a scene in broad daylight a Photographer must choose between the lesser of two evils:
- The foreground or principle subject is properly exposed, but the sky or other areas are blown out.
- The photo is evenly exposed. No area is over-exposed or blown out, but principle subject or other areas are very dark.
Counteracting this problem has become much easier if you have a camera capable of bracketing or shooting raw images and software to merge the resulting images. Some cameras such as the iPhone have built in HDR features, but this post is designed for people who want more control when enhancing their photos.
Assuming you have a camera that can shoot raw, there are two basic ways to make an HDR photograph:
- Bracket your photo.
- Slightly over-expose a raw photo.
1.Bracketing a photo means taking multiple exposures of an individual scene. A tripod is practically mandatory to make it work. Software like Adobe PhotoShop or Photmatix does a remarkable job with handheld shots, but even the cheapest tripod will make your life easier.
Bracketing has been around for years and was much more commonly employed in the pre-digital age. At most basic, bracketing is kind of a fail safe procedure where you take multiple exposures, usually ranging from 2 stops under to 2 stops over, in order to ensure you have a “good” shot. Digital Cameras have somewhat made bracketing redundant because the photographer has the ability to preview an image directly after the shot is taken.
Photos involving moving objects make bracketing useless. Enter the RAW!
2. Most DSLR cameras have the ability to shoot RAW. RAW photographs retain more image info than the initial photo shows. White balance and exposure settings are recorded and saved into the file allowing the Photographer to make key changes in post processing.
At the time on shooting, aim to achieve a properly or evenly exposed image, erring on the side of slightly over-exposed. Digital cameras retain more information on the high end or white area of the spectrum. It’s easier to tone down the highlights in post processing than it is to pull value from the dark.
Moving on to post processing, we enter a three step procedure:
- Make copies of your Raw photo with different exposure settings.
- Merge the multiple Raw files to a single HDR file.
- Tweak as needed in PhotoShop.
Save up to three versions of the file with different exposure settings. I add -2, –, +2 to the end of the file name to help distinguish which exposure is which. It’s as simple as that. Sometimes you’ll only need two exposures.
2. Next we make an HDR image. PhotoShop has an HDR tool (File menu, Automate, Merge to HDR pro), but I’ve become a big fan of an application called Photomatix. It is easy to use and ridiculously powerful.
The set up here is quite simple. You load your bracketed photos. The software will prompt you to tell it which exposure is which. Using the naming convention I suggested above makes this a no-brainer. There are options for de-ghosting and other options, but you can uncheck them because in this method all your exposures come from an identical source. You might want to grab a coffee at this point because depending on the resolution of your photos and the speed of your computer it could take a while. When you see the resulting image I think you’ll agree it was worth the wait.
The initial processing should display a photo that looks flat out fantastic and you could simply press the process button and call it a day. Feel free to play around with the settings and presets because there are all sorts of whacky and whimsical results to be found. Again, for the purposes of this primer, we are aiming to make a photo that looks real, but better than a single exposure could achieve.
3. Move on to PhotoShop. You may not need or desire this step, but I find a little fine tuning in Adobe’s Image Editor can really make your picture pop. Cropping, curves adjustments, selective dodging/burning and spot healing can make a big difference. I only recently discovered that Windows 7 comes with a pretty handy image editor so if you don’t have the budget for PhotoShop go that route.
Generally I find the more I play, the more I learn. I hope the preceding post has helped you learn a little more about making better memories with your photography. Happy snapping!