Archive for the ‘Dynamic range’ Category

What is HDR?

I was introduced to HDR a few months ago through another flickr member.
The first thing you’ll notice in a HDR image is that the light is evenly distributed and the tones are more pronunced than a picture exposed using normal digital techniques.

Basically it means when you employ this technique you can produce images with a very high dynamic range for exposures in other words when you expose your picture most of us usually follow the light meter inside our cameras and some of us use external light meters: based on these readings we expose this picture but we will never have an exposure which is technically perfect i.e. we cannot have all the shadows exposed in a way so that every detail in the dark area is visible and at the same time expose all the highlights to avoid burn outs. Basically, it is difficult to acheive this dynamic exposure range using film, slide or digital techniques. HDR helps you to acheive that thus allowing you to create some nice and surreal images.

I hope you guys understood what I wrote up there anyways here is the definition

In computer graphics and cinematography, high dynamic range imaging (HDRI) is a set of techniques that allow a far greater dynamic range of exposures than normal digital imaging techniques. The intention of HDRI is to accurately represent the wide range of intensity levels found in real scenes ranging from direct sunlight to the deepest shadows.”

You can wiki this for more information.

all right since we now know what HDR means so how do I generate one?

How do I generate a HDR Image

Things you need to generate a HDR image
1.Most importantly your image(s) itself.
You would require an image that has been bracketed for +/-1EV(Exposure Value) i.e. basically you shoot the same picture with different exposure settings, one slightly overexposed(1 stop), one slightly underexposed(1 stop) and one with exact exposure settings as suggested by your camera.
2.A software that can generate a HDR
PhotoMatix Pro is a popular one (HDR, Tone Mapping)
You can also acheive HDR using Adobe Photoshop CS2

Original Image

Stupas and Clouds - Original
HDR Image

Stupas and Clouds - HDR

Original Image

Cars Bangkok - Original

HDR Image

Cars, Bangkok - HDR

Some interesting links