What is HDR? and how is it made?

Question

Can someone explain me HDR images a little, and how do I manage to create one? I saw some HDR images, and they look really great but I don't understand what they are and how they are made?

Tnx

Answer 1

HDR's (high dynamic range) images are composites that use multiple over and under exposed files to increase the amount of detail in the shadow and highlight areas.

The number of exposures depends on the scene and can range from three to eleven, or even more. This all depends on the particular scene. An outdoor scene in daylight may only require three exposures, whereas an indoor industrial setting may require 7, 9 or even 11.

An example of 11-exposure HDR's can be seen here:

http://www.lenswork.com/enhanced/preview...

Page through to the Energy Plant photos by Jim Laurence.

As for how to combine these exposures, it's not as easy as simply using Photoshop. HDR's look very odd when first created as the tones are not placed correctly within the image. To correct this, a third-party program such as Photomatrix  http://www.hdrsoft.com should be used to remap the tones into their correct relationships.

Answer 2

They're done by bracketing.  You take 3 pictures at different exposures, usually -2, level, and +2.  The under-exposed one brings out the details in the bright areas, the over-exposed one brings out details in the dark areas.  Then they're merged together with software -- there are tons of different packages, so I won't go into details, but do a search for HDR software.

Your camera may support bracketing.  Check the manual.  If not, you'll have to do it manually by taking three pictures.

Oh...and use a tripod to make sure you get three identical images.  Helps put 'em together later.

Answer 3

As said HDR is High Dynamic Range I would add to the above that if you are shooting RAW you can bracket post production from a single RAW file and sometimes it may take more than 3 bracketed shots to get the effect you want

Here are a couple of good places to start out researching this

http://en.wikipedia.org/wiki/High_dynami...

http://www.cambridgeincolour.com/tutoria...

Answer 4

http://www.flickr.com/photos/little_pook...

Five identical photos - camera mounted on a tripod, same aperture setting (so the depth of field stayed exactly the same)--just different shutter speed, in M (manual) mode.  I used a shutter release cable to minimize movement. Or else I would have used self-timer.

All merged together in Photoshop CS3E.