HDR - A What, Why, and How Guide.

What?
Higher Dynamic Range (imaging) is a tecnique developed to improve the overall tonal and dynamic range of a photograph to produce a more visually accurate photograph. it is achieved by merging 3 or more photographs of different exposures together.

Why?
HDR is used mostly when a photographer cannot reach a equalibrium between underexposed areas and over exposed areas in the same composition.


Using HDR programs/software allows for both under exposed, and over exposed images to be merged into one primary image, giving a detailed and more realistic photograph that couldnt have been achieved with one exposure.


How?
Now you have the basic understanding of HDRi, im sure your keen on what the process is to achieve theses final images!

Tools for the Job:
A RAW editor such as Aperture, RawShooter, or Photoshop. Secondly, the HDR program. I use Photomatix.

A tripod is also a must to prevent "ghosts" aka movement through each shot.

Source Images:

Tecnique 1
There are a number of ways to capture your sources - i will show you the most popular, and later, i shall follow up with another tecnique.

1. First of all make sure your camera is saving your exposures as RAW - this holds more light/dark/colour detail than a JPEG

2. Set your camera to Auto Exposure Bracketing (AEB) of -2 / +2 stops. This will allow your camera to take 3 subsequent pictures at different exposures.

3. Compose your shot, and set the camera up as your normally would to take a picture. Press your shutter realease button 3 times. You will notice the images in your display each have a different exposure. ONe under, right, and the last, over exposed. You now have the 3 shots required to produce a HDR image.


Tecnique 2
The other way to produce the 3 shots needed is to take 1 photo and adjust the exposure -2 / +2 stops in a RAW editor, and save each seperatly exposed image.

Generating your image:

1. Load your three images into photomatix and from the HDRI menu select Generate HDR.

Once your image has been composed, you will se a rather shocking merge of all 3 exposures pop up on screen. Dont panic! It ow needs to be tone mapped.

2. Goto the HDRI menu and select Tone Mapping. You will now see your image in a new screen, as something more usable and representative of a HDR.

3. Here is where all the magic happens. The trick now is to adjust the settings to get a nice balanced image. The are no hard and fast rules for this - it is all down to each individual photo and your personal preference.

Luminosity:
Adjusts the brightness of the shadows.

Strength:
Controls the strength of local contrast enhancements.

Color Saturation:
Controls the saturation. AKA the intensity of the colours.

White Clip - Black Clip:
Contrls the contrast in highlighted and shadowed areas.

Final Image:



The final image can represent anything from a more natural feel to something more hyper or extreme!



Have fun with the software and always experiment. In time you wil develop your own tastes and tecniques!

Thanks another nice and easy to understand tutorial

Will take some pics and have a try at this during the week hopefully

Thanks Carole - things are so much easier to understand when kept simple - i hate going into the science and maths of these things LOL

Another great guide K! Added to the helpful threads sticky

A nice easy to read guide. Even novices like me can understand them

Hope to see one off you soon then Wolfie!

By the time I manage it, everyone would of forgotten

I have just read this and was wondering what HDR was you have explained it so well ....Thank you...
Sue

Thanks K, I was looking at HDR work and now know how it is done. I just wish I had photoshop to give it a go......

You can download the photomatix trial Fudgley

http://www.hdrsoft.com/download.html#pmp