Monday 10 June 2013

A Variety of Scenes with Differing Dynamic Range

I have been familiarising myself with assessing scenes of differing dynamic range so that I could make informed judgements on how 'best' to capture setting ranging from low contrast to high contrast. I saw completing this project in my course as a means of being able to effectively recognise the different effects various lighting had on a scene and henceforth the camera's ability to record it.

Photograph 1
   I quickly came to realise that for me, it was a lot easier to find high contrast scenes than low contrast ones - when you were out looking for either. I could put this down to sunny weather only but I also felt I started to notice the effect highly reflective surfaces or light sources had on a scene, which in turn challenged my camera's dynamic range.

Photograph 2
   So it's not much of a surprise three of the five resultant images were of medium to high contrast. These three were offset by a required low contrast scene (Photograph 2) and one where I had deliberately searched for a setting where the levels of light were spread across quite evenly through (and within) the histogram (Photograph 5). I included this because I thought it would be a good example showing the range of light my camera could record.

   Speaking of recording, I also measured and recorded the lightest and darkest areas of each of the five scenes. I found some interesting results but as I had thought beforehand the main factor was the light. Overcast days obviously had lower contrast but with sunny days the contrast varied from medium to high. I found there to be at least one bright patch and one darker area within most scenes on a sunny day. Also more often than not I found there to be some object reflecting light on these sunny days.

Photograph 3
   I measured the lightest and darkest areas in the same way as in the previous exercise: using spot metering and zooming in to the lightest and darkest areas. Here are my results:

Photograph 1: The camera settings for this scene were f/7.1, 1/125 and ISO 800, with an exposure bias of +0.7.
The darkest area (the bottom of the shop fronts) was metered at f/7.1, 1/20 and ISO 800 with an exposure bias of +0.7.
The lightest area (the roof windows) was metered at f/7.1, 1/2500 and ISO 800 with an exposure bias of +0.7.
This meant the scene had a dynamic range of 7 stops of light.

Photograph 2: The camera settings for this scene were f/8, 1/40 and ISO 200 with an exposure bias of 0.
The darkest area (the plants in shadow in the bottom right of the frame) was metered at f/8, 1/25 and ISO 200 with an exposure bias of 0.
The lightest area (the light leave in the distance) was metered at f8/, 1/80 and ISO 200 with an exposure bias of 0.
This meant the scene had a dynamic range of approximately only 1 and 2/3rds stops of light.

Photograph 3: The camera settings for this scene were f/5.6, 1/125 and ISO 400 with an exposure bias of 0.
Photograph 4
The darkest area (the shadows in between the columns) was metered at f/5.6, 1/25 and ISO 400 with an exposure bias of 0.
The lightest area (the sky) was metered at f/5.6, 1/1000 and ISO 400 with an exposure bias of 0.
This meant the scene had a dynamic range of approximately 5 and 1/3 stops of light.

Photograph 4: The camera settings for this scene were f/10, 1/80 and ISO 100 with an exposure bias of +1.
The darkest area (the door into the left building) was metered at f/10, 1/5 and ISO 100 with an exposure bias of +1.
The lightest area (the Sun's reflection in the glass of the left building) was metered at f/10, 1/800 and ISO 100 with an exposure bias of +1.
This meant the scene had a dynamic range of approximately 7 and 1/3 stops of light.

Photograph 5: The camera settings for this scene were f/5.6, 1/125 and ISO 200 with an exposure bias of -0.3.
The darkest area (the car tyres) was metered at f/5.6, 1/25 and ISO 200 with an exposure bias of -0.3.
The lightest area (the sun-lit tops of the buildings in the distance) was metered at f/5.6, 1/2000 and ISO 200 with an exposure bias of -0.3.
This meant the scene had a dynamic range of approximately 5 and 1/3 stops of light.

   As can be seen in the processed images, all of the images 'fitted' within my camera's dynamic range of 8 stops. While this was pretty easy for Photograph 2, it was a bit of a stretch for my camera to cope with Photograph 4 especially. My impressions I got from this project was there were a lot of high contrast situations to encounter, especially in sunny settings and judging how to capture these situations 'best' was important then and there - even if you intended to post-process them afterwards.
Photograph 5

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