f. HDR (High Dynamic Range) Mode
HDR mode enables you to take the same picture with different exposures, so
you can combine them later with image processing software to get a final
image. The final image will be closer to what human eye can see. The theory
behind the HDR photography is very simple. The human eye can see the light
in 20 different stops. This is approximately about 1000000:1 contrast ratio. A
high quality DSLR camera can capture about 14 stops at maximum. If you
sweep through all possible exposure values by taking multiple images, you will
get as close as possible to what human eye can see.
The HDR photos are usually taken in odd numbers as there will be an image at
the center exposure and equal number of images with the higher and lower
exposures. The exposure values will be calculated depending on the center
value. This parameter is shown as “Center” in the HDR menu. You will also
need to specify how much you want to increase or decrease the exposure at
each step. The higher the ratio, the wider will be the dynamic range. This
parameter is shown as “EV(+-)”. The final parameter is how many pictures you
want in total. This is shown as “Frame”. If you want three pictures for example,
there will be one at the center exposure, one at the high exposure and one at
the low exposure. If you want five pictures starting from the same center
value, the exposure will get high and down one step more. If you set EV(+-) to
2, the highest possible value for the frame value is limited to 5. This is due to
the technical limitations of the DSLR cameras. It is technically not possible that
a DSLR camera would be that fast in bulb mode.
The calculation of the exposure steps is pure mathematics. The formula is very
𝑛 − 1 𝑡ℎ&𝐸𝑥𝑝𝑜𝑠𝑢𝑟𝑒 =
𝐶𝑒𝑛𝑡𝑒𝑟
2
(34 )
𝐶𝑒𝑛𝑡𝑒𝑟 &𝐸𝑥𝑝𝑜𝑠𝑢𝑟𝑒 = 𝐶𝑒𝑛𝑡𝑒𝑟
𝑛 + 1 𝑡ℎ&𝐸𝑥𝑝𝑜𝑠𝑢𝑟𝑒 = 𝐶𝑒𝑛𝑡𝑒𝑟 ∗ &2
(34 )
If you set the EV(+-) to 1, the exposure will be multiplied or divided by 2. If
you set it to ½, the factor will be 1.41. If you set the EV(+-) to 1/3 the factor
will be 1.25 The exposure values will be calculated by multiplying or dividing
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