Thursday, August 13, 2015

Photography tips: What is twilight?

Everyone who owns a camera has photographed a sunrise or sunset at least once and it's well known that the 'golden hour' (the first or last daylight) is the best time for photography. I have countless photographs of sunsets (particularly from my balcony while living in Melbourne) but it was only once I started planning our trip to Iceland that I really researched the three different phases of twilight.
Each of the three phases relates to the position of the sun below the horizon.

Civil Twilight - (when the sun is between 0 and 6 degrees below the horizon)

Nautical Twilight - (when the sun is between 6 and 12 degrees below the horizon)

Astronomical Twilight - (when the sun is between 12 and 18 degrees below the horizon) 

Since it's pretty hard to tell sun angles when you can't even see the sun, here are a few pictures to demonstrate...

Melbourne Sunset - 13/02/13 8:14pm (f5.6, 1/200s)
When this photo was taken the sun had just dipped below 1 degree above the horizon, about 6 minutes before the official sunset for the day. There was still enough light to see clearly here, but I used a short shutter speed to capture the orb of the sun. This is definitely the 'golden hour'.
Melbourne sunset - 14/03/12 7:41pm (f1.8, 1/1000s)
From the same location taken just as the sun dipped below the horizon, right on the edge of sunset and civil twilight. Again, enough light to see but I used a short shutter speed to capture the silhouette of the church. No tripod required.
Melbourne sunset - 14/03/11 7:49pm (f1.8, 1/400s)
Same location, 8 minutes later - it's now civil twilight and the sun is about 2 degrees below the horizon. Still easy enough to photograph without a tripod.
Paris during twilight - 14/07/11 10:07pm (f2.0, 1/60s)
Different location but roughly the same angle, this photo was taken in Paris after sunset during civil twilight (about 3 degrees below the horizon). The lights of the Louvre are on, but they don't dominate the image just yet, you can still see the detail of the building with the available light. No tripod used still and I took a series of images to stitch together (hence the vertical lines in the sky, I should have been more careful with the exposure).

Also, something to be aware of, sunset was at 9:50pm, so during summer in Europe there's a lot of twilight (and if you go far enough north, no technical night at all!).

Chinchilla twilight - 24/01/15 7:32pm (f4.0, 1/3s, ISO3200)
This is nautical twilight now, sun is about 9 degrees below horizon, it's light enough to see but barely. White/reflective surfaces work well for photos but a tripod and longer shutter speeds are usually needed, this one also has a higher ISO. This photo was taken at SJ's parent's farm if you're wondering.
Devils Marbles - 08/05/09 7:49pm (f5.6, 1.6s, ISO1600)
Finding a photograph in my collection that was taken during astronomical twilight was difficult, I seem to photograph a sunset and put my camera away when it gets this dark. A photo of a city might have a more bluish sky during astronomical twilight rather than a black one.This photograph was taken from the campsite at the Devils Marbles, I had just come back from my sunset photo shoot (it wasn't a good one sadly) and dinner prep had begun. We had a fire going and nearby campers started a little fire twirling display. There is obviously some light from fires in the foreground but with a 1.6 second shutter speed you can still see clouds in the sky. I'd generally consider this 'dark' though.

Devils Marbles -(as for image above but lightened with software and has visible noise).
EDIT: My computer displays different gamma and contrast to most mobile phones, I'm not sure which is correct but if you're reading this post on a phone then astronomical twilight is probably better demonstrated by the above edited image.
Chinchilla - 24/01/15 - 10:32pm (f4.0, 30s, ISO3200)
And of course, once it's dark you then have the opportunity for photos of stars. This photo was taken a long way from any big city, the red glows near the horizon are from gas flares (from nearby wells and refineries).

So there you have it, a photographic demonstration of the three phases of twilight. The next step is determining when each phase actually occurs. For that, I use two main resources:
  • 'time and date.com' - as well as including the times for twilight phases for most major locations around the world, this site also includes times on moon phases and sun angles.
  • 'suncalc.net' - this one is really funky, it's basically googlemaps with the position of the sun displayed. Any point on the globe, any date and time. This one won't tell you the angle, but it will show you. I've used this both as a photographic resource and for planning the backyard. It's very cool (but that could be the geek in me).
And of course, for a sunrise you get all the same phases of twilight, just backwards.
Uluru and Kata Tjuta during sunrise
So what have I learnt? I will be in Iceland in December when the sun rises after 11am and sets at 3:30pm but nautical twilight starts before 9am and ends at 6pm, so I should have enough twilight to take plenty of photos!


Disclaimer: Tips provided on this blog are based on my own experience and research and anything I know you could probably discover yourself. These posts are written in the hope they are useful...though I make no promises.

1 comment:

  1. The best recipe for good sunset photo is the carriage of certain objects in the foreground. This can be a pond, or a mill for some expression. http://besthdrsoftwaremac.com/ plugins can help you with editing

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