Today I want to talk about a key component in Long Exposure Photography, and that is clouds and the streaks that they create in Long Exposure daytime images. I First met Sharon Tenembaum while attending the BW Visions Workshop – NYC in 2014. Sharon, an international Award winning Fine Art Photographer, presented herself willing to share all her help and support to raise our photographic standards.
In daytime long exposure photography, cloud streaks are created from the movement of clouds against the background of a uniform sky. When an area is bright one minute from the cloud (since it is white), and dark the next once the cloud has moved, and the relatively darker sky (blue) is exposed. This change of white to blue and blue to white creates the cloud streaks seen in Long Exposure Photography. Of course you don’t need a beautiful blue sky to get streaks, but the stronger the contrast between the blue and the white in the sky, the stronger the contrast of your streaks.
Cloud Formations and Velocities
Different cloud formations moving in different velocities will create different looking skies. I will present a few examples of the results created by the different cloud formations. The first example is of a ‘cotton ball’ like cloudy sky. This type of sky creates a distinct differentiation between the clouds and the sky and creates very defined streaks as seen in this example.
Sharon suggests, although I can tell you what the shutter speed was that created the steaks in this image, it doesn’t really mean anything since you need to take into account the velocity of the clouds. In this example my shutter speed was 2 minutes long and I remember the clouds moving very fast, on a different day the same clouds moving slower could have created the same streaks with a longer exposure.
The sky in the second example had what I call a ‘foggy / creamy sky’ there was no distinct definition of the cloud and the sky but rather the whole sky was creamy cloudy and through some certain areas, the white sky peaked thru. In this specific case the clouds were barely moving and you can see the result of this sky in the final image. The cloud formations seen on the still shot are still noticeable in the final image and the 3.5 minute exposure created a smooth creamy sky.
Additionally, different exposure times will give you different results of streaks as well. There is no set rule to the amount of time you should set your exposure to for certain result, since the type of streaks is also dependent on the velocity of the clouds. But in general, the longer the exposure (or the faster the clouds are moving), the blurrier the cloud streaks will come out, and conversely, the shorter the exposure, the more they will come out as regular still shot clouds. You need to know what result you want and adjust your settings accordingly by adding more or less ND Filters for more or less F‑Stop reduction..
To learn more or to purchase my ebook: How to Create Long Exposure Fine Art Photography, please go to www.SharonTenenbaum.com