Ö÷²¥´óÐã

Distance travelled ~ 516'168'000 km

(Tom Hewitson is the Assistant Producer on 23 Degrees currently working on episode two. Tom heads to Northern Norway on Friday - his first shoot on 23 Degrees - to film the Sun setting for the first time since May).

When I joined the 23 Degrees team I encountered a challenge I'd not come across before: filming the weather. Mother Nature is rarely willing to do a second take and she insists on working at her own pace, not ours. This can lead to a problem. Over the series we'll be featuring things like cloud formation, sunsets and ice melting. These events can often take many hours, longer than the duration of the entire series! We get around this problem by using time-lapse photography. It's a technique I haven't used before, so I thought I'd better learn pretty sharp-ish...

The principle is simple. Television is simply a string of images shown very quickly. In the UK we show 25 of these pictures a second and when we see them at this speed we have the illusion of motion. Normally the images are played back at the same rate they were originally taken, but time lapses are different. Pictures are taken over a much longer period of time, perhaps an image every few seconds. If we then play these back at the standard 25 frames per second we will see the action very much sped up. Hey presto, we can show an event that could take many hours in a matter of seconds! It's a great way of observing phenomena that we simply miss at our normal pace of life.

Before heading out on location I thought I should get to grips with time lapses so decided to do a test shoot. I'm fortunate enough to have a balcony right next to my desk, so for my very first attempt I decided to film the clouds going overhead.

Ìý

Ìý

For this I've used the Canon 5D camera we have in our office. A tripod was essential, as I wanted the weather to be moving, not the landscape! Finally, to trigger the camera you don't want to be pushing the shutter button by hand (not only would it wobble the camera, it would be very boring). We therefore have what's called an intervalometer; a device that automatically activates the camera's shutter at pre-programmed time intervals.

But before I could set it going it was time for some rough maths. Judging the speed of the clouds, I decided filming for about 10 minutes should be enough to show some good movement. As I wanted the final footage to last for about 10 seconds, I'd need to take 250 frames in total. This means I should take 25 pictures a minute, equating to a shot every 2.4 seconds. Unfortunately I could only dial in whole seconds into the intervalometer, so I decided to take an image every 3 seconds, which gave me 8 seconds of footage for 10 minutes of cloud movement.

Thanks to a phone call over-running I ended up filming for a little over 20 minutes giving me 17 seconds of footage, but it's better to have too much than too little. True, the footage is just of some fairly uninspiring clouds over London, but hopefully with this one done I can be a bit better prepared when I'm faced with that once a year weather event I need to catch on camera!

• Bookmark with:
• |
• |
• - What's this?