HDRI stands
for ‘High Dynamic Range Image’ where Dynamic Range is basically
the difference between the lightest and the darkest spot one can
capture in a photograph. So we can say that HDRI is a photograph that
composes a greater dynamic range between the brightest and darkest
areas of the scene than the standard photographs.
But generally when we
take a photograph at the standard exposure levels it is arguably
impossible to capture the both ends of spectrum in a single image.
Once our scene exceeds the camera’s dynamic range, the highlights
tends to washout to white, or the darks simply becomes big black
spots. So in order to capture a great Dynamic Range between the
lightest and the darkest areas of a scene photographers nowadays have
developed many methods using the latest photographing techniques and
advanced post processing programs.
One of the most
common methods of capturing a HDR image is by capturing 3
different photos of the same scene at different exposure levels and
then blending or stitching them together with a post processing
program. In a more elaborated way, in this method a photographer
captures a scene with a range of bracketed photos, i.e. the photo of
the same scene captured with different combinations of shutter
speed/aperture/ISO. It is usually taken in order to produce different
sets of images with varying ‘Luminosity’ and ‘Depth of Field’.
Then these photos are stitched in a post processing program where the
highlights, mid-tones and shadows of these images are blended
together to produce a single image comprised of the most focused,
well lit and colorful parts of the scene.
Image 1.0 Exposure Level -2
Image 2.0 Exposure Level 0
Image 2.0 Exposure Level +2
In this method all
we need in order to create an HDR image is a ‘Camera’ with an
‘Auto Exposure Bracketing’ function, a ‘Tripod’ or a
‘Stabilizer’ and a HDR Photo Blending Software.
1. We will start by
putting up our camera on a tripod. This will help in avoiding any
sort of shake in our photographs as we require to capture 3 images of
the scene from the same position and angle. A little bit of shake can
sometimes get really difficult to align in post.
2. Next we will turn on
the AEB function of the camera with the exposure levels ranging from
-2 to +2. This feature will helps in capturing photographs at the
exposure levels of -2 (capturing all the dark color variations of the
scene), 0 (capturing all the variations in normal colors of the
scene) and +2 (capturing all the variations in the bright colors of
the scene.)
3. Also enable the
‘continuous shoot’ function from the camera functions. This
function will helps us in clicking multiple photographs on a single
click which will help in reducing the chances of camera jitter while
pressing the click button thrice.
4. Once we are done
with the image capturing part we are ready to blend them with a HDR
photo blending program capable of merging the images using different
sets of algorithms. One of the most advanced HDR photo blending
program is 'Photomatix' due to its powerful, fast, advanced, and full
featured options.
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