- A camera
- A sturdy tripod
- Photoshop CS3 or CS4
- Knowledge of manual exposure or exposure compensation
What is HDR
HDR has nothing to do with "high definition". Rather, it simply stands for "High Dynamic Range". Cameras are capable of capturing a certain range of tones , light to dark, and the simple fact is that this range is limited compared to the human eye. HDR's are images created from several pictures taken at different exposures, then combined together in imaging software like photoshop, creating one image that can display a broader range of tones.
When to use HDR
I don't like spending hours in front of the computer. The amount of images I have to composite in Photoshop is directly proportional to the number of times I bang my head on my desk. I'd just rather be out shooting. So here's the deal. HDR is quite a production to create a single image. Don't do it unless the situation really requires it. The image above is a reasonable example of a situation where HDR can come in handy. If I expose properly for the pier, the sky will be too bright and I will lose the color. If I expose for the sky, my pier becomes a sihlouette and I will lose the detail in the blue buildings. I could solve this by lighting the pier, but I don't have enough speedlights in my bag to light a pier! Another alternative would be to use a graduated ND filter to darken the sky in camera, but the graduation in tone is going to fall on parts of the pier and look just a bit hokey. Hence, many of the HDR images you will see are of large structures against a dramatic sky. If your subject is small enough to illuminate, think about using an off camera speedlight first or adding a graduated filter. If that doesn't solve your exposure issues, time to suck it up and put together an HDR.
How to Shoot HDR
We are going to need several images of different exposures that will layer seamlessly on the computer. So here's the deal, use a tripod. Lining up images that are shot at different angles equals more head banging on your desk. Keeping your camera steady prevents this. You can save yourself additional head banging by shooting in manual white balance. Auto white balance can cause the camera to make micro adjustments that you are not expecting as you shoot. Shoot everything as consistently as possible in camera to make the images combine smoothly. To keep your depth of field and focus consistent, set your aperture manually and use manual focus. I also recommend the use of a cable shutter release to prevent camera shake as you press the button. This can also be achieved by putting the camera in timer mode. When you're settings are locked in and you're ready to shoot, resist the urge to take 5000 photos and combine them all to get every possible exposure. Bracket by about 2-3 stops by tweaking your shutter speed for each shot and you should have plenty of RAW material (pun inteneded) to work with. Check your LCD to make sure you have all the bases covered in terms of a properly exposed foreground and background. Below, you can see my darkest image has a nice looking sky and my brightest image is starting to bring out some detail on the pier.
Once you have your shots, open Photoshop and go to File>Automate>Merge to HDR. For the shot above , I took 4 photos ranging from +1.85 stops down to -1.12. If I wanted a full blown "fantasy" HDR look, I could have captured a broader range, say 3 stops. In this case, I just wanted to produce a realistic looking photo with the dynamic range slightly extended. RAW is generally a better choice than JPG for this but JPG's can work just fine as well. Once you have your images selected, click "OK".
Photoshop will diplay a hazy looking 32-bit file that doesn't look so hot on your screen. This is normal. We need to convert this down to 8 bits to produce a nice looking JPG that will display properly on monitors. Go to Image>Mode>8 bit. Set the pull down menu to "local adpatation". There are other ways, but without getting ultra scientific, this method is most useful for photographers. Click the pull down menu for "toning curve and histogram". Now you can tweak the curve, radius and threshold to your liking. I put a slight s-curve in mine to bring back the global contrast. Increasing the radius can help the local contrast and sharpness but be careful not to set this too high or you will create artifacts. The amounts will vary based on your image resolution and other factors. You may then wish to do some final levels adjustments and sharpening as I have here. I find that HDR images almost always need some "unsharp mask" to give that little extra pop before saving.
Go to Filter>Sharpen>Unsharp Mask and adjust the setting to taste. Zoom in to 100% view to get and idea if your sharpening is causing artifacts or a "halo" effect. Again, the sharpen setting will vary a bit based on your image size and intended output. Now let's get out and shoot!
Images and Article © 2009 - Author Rob Szajkowski