HDR imaging allows capturing images at greater contrast sensitivity than with 'standard' techniques. So called LDR (low dynamic range) techniques.
It is omitting part of story when I describe it this way, but let's say that a standard display is your monitor. It would 'standardly' have three channels Red, Green, Blue, of which each can have intensity 0 - 255 (8 bits per channel). HDR image may have range far greater than that; e.g. 0 - 16383 (14 bits per channel).
HDR image as such can not be displayed on a standard screen whilst preserving all that contrast information. Thus, its contrast range is reduced first to 0 - 255, losing some details and preserving some details. This process is called
tone mapping. There are many many ways to map HDR image to a LDR image and achieve from very natural looking photos to very supernatural looking photos.
Like Samantha mentioned, some cameras are capable taking HDR images in a single shot. They are usually [much] more expensive. Another technique, doable with every LDR camera that can change exposure, is:
- take multiple shots of same subject in different exposures
- bind those different exposures together to obtain a HDR image. Normally, one will need a tool to do that.*
Whether you are going for one or the other way to obtain HDR images, I recall a free tool named
LuminanceHDR, that offers a few tone mapping operators. It can also bind differently exposed LDR photos into a HDR photo. Iirc, it was allowing manual shifting of pictures, thus allowing one to work with multiple exposure photos taken without a tripod. One weird thing about the tool, it seemed to give completely different results when ran on Windows vs Linux.
Hope this helps a bit. :)
* - Keep on mind, the more exposures, the more noise will be introduced to HDR. Thus normally
three at -1, 0 +1 EV** are good. Or -2, 0, +2. Sometimes you may decide to go with
two: -1, 1 EV. Or -2, +2 EV. Aim for lower (lowest) ISO value when taking photos. Or be ready for more noise, that is.
** - Exposure Value; you should find them with ease in settings! The EV 0 represents the
normal setting. A positive value means
overexposure (brighter result, but captures darker details of the subject), a negative value means
underexposure (darker result, but captures brighter details of the subject).
this is really interesting topic, and new knowledge for me. I use to use HDR preset in Lightroom to make the digital photo HDR. But shooting HDR with camera technique is very interesting. Thank you for sharing
I've been playing around with different HDR methods since creating the thread, and I feel the one which works best for me is through photoshop, method below a couple example images:
[Dead Images removed]
Method:
Shoot an image using RAW
Open the image in Adobe Photoshop
Add one image as -2 , +2 , 0 exposure
Combine the images using the HDR toning feature
Edit contrast, vibrance, clarity ect. to your taste / to suit the image.