Exercise 9: SCENE DYNAMIC RANGE
According to the earlier exercise (exercise 8), I had to run a test to find out camera’s dynamic range, where as in exercise 9 the focus is more on the dynamic range of the scene. I had to choose five different light conditions to measure the dynamic range of that particular scene. That means I had to find out what was the meter reading for the darkest and the brightest area in the picture.
For this exercise, I decided to take a short walk around my condominium and shot some images with different light conditions. All of the following photographs were taken at f/4; I had fixed the ISO to 320 also kept the EV constant. This way I could measure relative brightness. For this exercise, I was dependent on camera’s in built metering. To measure the correct exposure for the brightest and the darkest area I zoomed in maximum to the respective areas and noted the exposures.
Scene 1: Indoors
This scene was shot indoors and had were good contrast of brightly light and shaded areas. The brightest area was the white wall near the planters in the balcony, and the darkest area was near the center table.
- Exposure range on 19 stops
- At 100% there was obvious noise in the dark areas.
- Noise could not be reduced to a satisfactory level by using Lightroom noise reduction tool.
- I feel by using the flash or the reflectors the exposure range can be pooled down by few stops. That can help in reducing the noise in the dark areas and make the image more useable.
1/125 sec @ f/4, ISO 320, Focal length 36mm, EV -1/3
Scene 2: Mixed light
This place was mostly under shaded area with little sunshine in the corner. However, due to the square holes in the wall there were contrasting areas of brightness.
- Exposure range was 4 stops.
- At 100% the image had slight noise in the dark areas.
- I could remove the noise very easy with the noise reduction tool in Lightroom 3.
1/800 sec @ f/4, ISO 320, Focal length 66mm, EV -1/3
Scene 3: Shade
The area was under shade and has many dark areas. In spite of that there was a good amount of natural light.
- Exposure range was 10 stops.
- I did notice some noise, when enlarged it to 100%. However it was very minor and could be reduced to none by very slight adjustment to the slider in Lightroom.
Scene 4: Bright light on a cloudy day
This shot was taken 10:49 in the morning. Sun was shining, but due to light clouds it was not very strong. This scene provided challenging color range. Matured dark tree in the background provided good backdrop for the young, bright green leaves.
- Exposure range for this scene was 6 stops.
- At 100% the noise level was low enough to ignore.
- Due to the brightness of the scene the shutter speed was very high. If it were not for this exercise, I would prefer to lower the ISO to 100 and bring down the noise.
Scene 5: Towards the sun
This scene provided good play of light and shades. The sun was hiding behind the thin layer of clouds. The Sky was very brightly lit. The areas in the building and at the parking were under shade.
- This scene exceeds camera’s dynamic range, Exposure range 14 stops.
- Hence the sky is completely washed out. The Dark areas also have noise beyond salvation.
It was interesting to go through this exercise. It has helped me to understand that it’s just not enough to know the dynamic range of your camera. It is also important to understand the range dynamics of the scene. Once you comprehend that, it is even more important to do the exposure management. This can be achieved in two different ways.
Accept the scene dynamics
- If I take this approach, I will try changing the composition to avoid the highlight clipping.
- In case I don’t want to change the composition, I would keep the detail in the highlights as much as possible and compromise with the details in the shadow.
There is a very good in depth read on Wikipedia regarding the “Zone system” by Ansel Adam and Fred Archer. http://en.wikipedia.org/wiki/Zone_System
Note: At times, this kind of scene dynamics can be quite useful in creating beautiful silhouettes.
Bring down the dynamic range
In this scenario, I would do that following:
- Recompose the scene
- If possible introduce artificial light by using flash or the reflector
- Use polarizing or ND filters to bring down the highlighted areas.
- Go for multiple exposures and use the HDR technique to reduce the range difference
- Underexpose the image to avoid the highlight clipping and then process it in Lightroom.