Exercise 4.2 – natural light through the day

All of these images were taken on 1 August 2016. The view is my back garden; the main series of images is taken from a first floor window, looking approximately ENE. According to The Photographer’s Ephemeris, sunrise occurred at 0523 and sunset at 2045 (8:45pm)

Unfortunately, the day I chose was the first dull day after the July heatwave, so there are no full-sun images. I will include some full-sun comparison images in a later posting.

All images were made with a Pentax K-1 and 24-70mm lens used in manual mode. RAW images were imported into Lightroom for  export as small JPGs for this blog. The only adjustment made was to standardise the white balance of all images at the ‘daylight’ setting (5500K and +10 tint on the green-magenta axis) to allow direct comparison.

The scene includes an area of sky in addition to the features in the ground. I found that setting my exposure to zero the meter would overexpose the sky, so the images presented have an effective bias of -1EV which optimises the histogram at the expense of slightly darkening the foreground scene, as the examples above. Normally I would make localised exposure and contrast adjustments in Lightroom to subjectively correct for this, but I have resisted the temptation on the grounds of objectivity.

Around dawn, there was a clear sky with light clouds.

30 minutes before sunrise, overall light levels are low and the colour is distinctly cold-toned. There is a big contrast between the sky and the unlit foreground.

A few minutes before sunrise the eastern sky has a distinct pink tone, rather bright at the horizon where the sun is about to rise, and the foreground is still unlit. The overall scene brightness is +4EV from the previous image.

20 minutes after sunrise, the sun is in the picture frame (but behind trees) and the sky in that direction burns out, but retaining the last of the warm tone. The surrounding vegetation leaves the entire lawn in shadow but clouds elsewhere in the sky are acting as reflectors and the scene has an overall flat lighting. The overall scene brightness is about +2EV from the previous image. Overall colour is rather cool-toned.

Through the morning, a light overcast developed and became denser. In these images the sun is out of frame to the top right and its position could be seen, although hazy. The light quality is soft and directional, similar to using a soft-box flash in a white-painted studio and there were moments when it cast distinct shadows (0820 image). Overall light levels are increasing, by approximately +1EV between images and the colour temperature varies with the density of the clouds. The light is warmer-toned when the sun is able to cast a shadow, and cooler-toned when the lighting is more evenly distributed; a demonstration of Mie and Rayleigh scattering effects.

Through the afternoon, the cloud became thicker and there were showers from about 1500 (3pm). Overall, the light falls off (darkest in the central image which was taken during rainfall) and is slightly cool-toned. There is now no directionality, with even diffused lighting from the entire sky-dome. Although there are no distinct shadows, shading can be seen below the furniture and at the left of the shed, where objects are blocking a significant proportion of the sky.

The final set of images are taken in late evening around sunset. The overcast sky means that there was no ‘fiery’ sunset and we see the light getting colder with time. About an hour before sunset, overall light level is about -3EV from mid-afternoon. Immediately after sunset, it has dropped a further -5EV, and another -3EV in the following 20 minutes.


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