The Eldridge Family

Calculating Timelapse Intervals

October 5, 2017
Timelapse, Tutorial, Calculator, Photography
There are plenty of timelapse calculators out there, and almost all of them work great at calculating timelapse intervals. But we just wanted to share to people how we do timelapse calculating, and break it down for you.

Step 1 – Visual Calculations

Before you start punching numbers into the timlapse calculating app that you just downloaded, you need to think about your scene and your project.

The Scene
You need to work out how long you need to shoot the scene for the action or effect to take shape. For example, we recently shot our 5 Hour Timelapse, which was of the tide going out and the sun setting. The reason it was 5 hours was because thats how long it took for both of those things to occur. We wanted the start of the clip to be sunny and at high tide, and the end to be a sunset and low tide.

You might be shooting a boat going past on a river. Well, for that you need to have a either timed it on a previous occasion, or have a good understanding of how long it will take. What about people moving in and out of trains on a platform… Well, get the timetable, look at when bust trains are due, go there on a previous day and assess.

No matter what you are shooting, you need to have an understanding of how long it will take and when to start the process. For the example below, lets say we decided on a 2 hour time block.

Your Project
This totally depends on what you are making, and is used when calculating. The basic question… How long do I want the finished timelapse to go for? Its all up to you, but keep your viewer in mind. You will find most timelapses go for a very short amount of time. Maybe 5 seconds to 20 seconds. Many timelapse projects are timelapse compilations. You need to come up with a finished product time. For the example below, lets say we want a 10 second video at the end.

Step 2 – Interval Calculating

By now, we have 2 numbers:

Total Event Duration: 2h or 120mins
Finished Video Time: 10secs

The next number we need, is the frames per second that you want for the finished video. I use 24fps, but you can use any number you like. Personally, stick to 24 or 25. Now we have another number:

Frames Per Second: 24

Now for the calculation, which is actually quite logical. Once you get this, it all becomes easy.

You want a video that has 24 frames per second, that goes for 10 seconds. So if you multiply those, you get 240 frames, or 240 photos.

Now we know how many photos we need to make the video, so all we have to do, is spread out 240 photos over the total event time which for us, is 120mins.

120 divided by 240 photos = .5min or 30 seconds.

If you don’t want to do the fraction conversion, you can just convert the event duration into seconds. In our example, 2 hours = 120 mins = 7200 secs.

So, you would do this: 7200 divided by 240 = 30.

This timelapse calculation says that if we take one photo every 30 seconds for 2 hours we will have enough photos to make a 10 second video at 24 frames per second.

There are plenty of apps and websites out there that will let you punch in the numbers, and they all work great, but do try to understand the process and logic behind calculating timelapse intervals, to give yourself a better grip of whats going on.

Once again, thanks for reading, I hope it helps you out.

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