photos from Wikimedia Commons

HDR images contain more dynamic range than a standard image. HDR images are files that have a lot more colors (color depth) available. You usually are working with an 8 bit file.

8 bit file = 16.8 million colors (bit depth you are usually working with)

16 bit file = 1.1 billion colors (if you shoot RAW you can convert your files to 16 bit)

32 bit file = Octillions of colors

You will be converting the 32 bit file to an 8 or 16 bit file that will contain both shadow and highlight detail.

In the above example, with a normal dynamic range image you could display detail in the window, or in the interior of the building but not both. An HDR image can display detail in both using tone mapping.

Step 1 -  CREATING YOUR IMAGES

You will be combining a variety of images for your finished 32 bit HDR file. Place your camera on a tripod if you can. If not, take all of your exposures with a particular landmark in the center of the frame. Start with an image that has correct exposure, then create one or two more on each side increasing and decreasing each exposure a stop or 2.

Example -2, -1, 0, +1, +2 or -2, 0, +2 or ?. You can do this by using your exposure compensation setting or auto bracketing if your camera has it (see me for details for your particular camera).Change your exposure by adjusting shutterspeed so your depth of field stays constant throughout the images. You can do this by using your camera in aperture priority or manual mode. See me if you need help. If your camera has a RAW option, us it and convert to 16bit files.

Step 2 - CONVRTING TO 32 BIT HDR FILE

Once you have created your files place them in a folder and open them all in Photoshop. If you want to view all of them at once go to WINOW>ARRANGE>TILE HORIZONTALLY. Select a window, zoom until you can see the entire image, and then go to WINDOW>ARRANGE>MATCH ZOOM AND LOCATION. Your mission is to get some of the detail from your under and over exposed files into the correctly exposed file.

Go to FILE>AUTOMATE>MERGE TO HDR.

Select USE FILES, click on ADD OPEN FILES. Leave the ATTEMPT TO AUTOMATICALLY ALIGN SOURCE IMAGES selected. Hit OK. Wait.

Your file will then open up in a window like this:

The displayed image is the merged result. It is just a preview. Drag the slider under the histogram to see the available dynamic range. If you don't want to use all of the files (maybe one doesn't line up correctly), uncheck it and wait for the new preview. Hit OK.

An image will open in Photoshop that has (RGB/32) in the title.This is the high dynamic range file. It will look flat and not very interesting, but it has a lot of room for adjustment. SAVE THIS FILE NOW so you can reload it without having to rebuild it if you want to work on it again.

Step 3 - TONE MAPPING

Go to IMAGE/MODE/16 BITS. A window with pop up with some tone mapping options.

Note - If you have the PREVIEW box selected  you will see the effects of each option as you apply them.

Next to METHOD you have four options to choose from:

EXPOSURE AND GAMMA - Drag the GAMMA slider left or right to increase or decrease contrast, drag the EXPOSURE slider left or right to lighten or darken the image.

HIGHLIGHT COMPRESSION - This option does not allow you to make any user adjustments (except loading or saving custom curves).This will reduce highlight contrast in order to brighten the rest of the image.

EQUALIZE HISTOGRAM - This option does not allow you to make any user adjustments (except loading or saving custom curves).This will spread of the peaks and valleys of the histogram so the image looks a little more even (looks a little punchier than highlight compression).

LOCAL ADAPTION - This has user adjustments. Probably the most useful option. You can adjust the Radius and Threshold sliders, and manually adjust the histogram curve. The Radius and threshold are similar to their counterparts in the unsharp filter. Like the unsharp filter, watch out for halos. Be sure to adjust the curve. Spend some time experimenting here.

After you are done, hit OK.

Step 4 - THE KITCHEN SINK

You now have a 16 bit file that can still withstand a lot of adjustment.

Try IMAGE>ADJUSTMENT>SHADOW/HIGHLIGHT. Click the SHOW MORE OPITONS BOX. Use this as you would for any image. In the color correct section in SHADOW?HIGHLIGHTS you can increase or decrease saturation. Try bumping up the MIDTONE CONTRAST slider to get some black back in the picture.

Use any other exposure adjusting techniques you know (try an S-curve to increase the contrast a little more).

When you are done you can convert to an 8 bit file - IMAGE>MODE>8 BITS

Photomatix

Photoshop does a good job of creating realistic HDR images. If you are interested in making some of the extreme HDR images with unrealistic tone mapping check out Photomatix. You can buy it as a stand alone program or as a filter for Photoshop. Here are some examples from their user gallery.

Converted with Photomatix

Your assignment will be graded using these criteria:

From Mr. P's Photo Rubric

Vision:
Is you image original, innovative and daring, or just another example of the same old thing? Does it fulfill the requirements for the assignment (see assignment requirements above) ?

Aesthetics:
Have you used the appropriate elements and principles of design that would enhance your photograph or did you just shoot what was in front of the camera? Have you used good composition or did you just place the center of interest in the center because it was easy?

Mechanics:
Camera Techniques: Is the image sharp/in focus? Is the exposure correct? Was the appropriate aperture/shutter speed used (if applicable for your camera), did you find the best angle?

Computer Techniques: Is the image sharp/in focus? Is it resized correctly? Is it color corrected and sharpened?

Presentation: Is the artwork presented in a professional manner as outlined in the assignment?

Good luck