The Packafoma Post is the periodically persnickety post-production blog of Packafoma LLC, featuring articles on Blackmagic DaVinci Resolve, Adobe Premiere Pro, video production, photography, website design, and Mac OS.
- Calculate shutter interval, target duration (final clip length), or event duration (recording time)
- Optimized for iPhone and iPad
- No advertisements
- Only 99¢
I was recently searching for a good time-lapse calculator online and discovered a number of free or cheap time-lapse apps. However, each of them exhibited the same frustrating flaw. The app would ask you to enter the recording duration and shutter interval. It would then calculate the duration of the video clip that would result. This could be useful on occasion, but most of the time it’s backwards.
I usually know how long I would like the final clip to be and how long I plan to continue capturing frames to cover the event (approximately). It’s the interval variable (time between exposures) that I need to calculate.
So I decided to develop my own solution. In addition to serving as an intervalometer, my time-lapse calculator estimates the memory card storage capacity that will be required. The storage calculations are calibrated for RAW and high-quality JPG settings on my Panasonic GH3 but will provide a general estimate for any DSLR or DSLM based on megapixels.
I created the web app to save myself some time (no pun intended), but my mama always taught me to share! Hopefully, other photographers will find it useful.
Time-lapse tips and example: New York City Marathon in 4K Ultra HD
The example above captures runners passing through Brooklyn at the 10 kilometer checkpoint of the New York City Marathon on November 3, 2013. The participants are headed north on 4th Avenue along the western edge of Park Slope towards Downtown Brooklyn, and, because the D and R subway lines “run” underneath 4th Ave, there are even more people traveling this corridor beneath the surface!
I shot this time-lapse video with my Panasonic Lumix GH3 using my calculator tool to determine the time between shutter activations. In the GH3’s time lapse mode, I set the Shooting Interval to every 15 seconds and recorded for 7 and a half hours. The result was a clip that was about 1 minute long when imported into Adobe Premiere Pro as an image sequence at 30 frames-per-second.
I recorded all 1800 stills in RAW format (.RW2 on the GH3). Thanks to the storage estimator, I knew that I could fit the necessary 36 GBs on my 45 GB SD card. The RAW image format allowed me to really maximize the dynamic range of the photos in Adobe Lightroom before importing them into Premiere. Even though I used aperture priority mode so that the shutter speed would automatically adjust with each exposure, it was still difficult to predict how the light would change over the course of a day. So having flexibility in post was crucial.
Here’s an important Adobe Premiere Pro CC tip for importing image sequences: The frame rate of an imported image sequence is determined by the Indeterminate Media Timebase setting in Preferences > Media. It is not determined by your current sequence settings. (By the way, I bet you read that as Intermediate Media Timebase. Take another look.) I wish Premiere would simply allow you to select the frame rate during import, but I have no shortage of gripes about Premiere Pro.
And finally, with the full 4:3 aspect ratio of the Micro Four Thirds sensor and a resolution of 4608×3456, I had extra pixels to play with, particularly in the vertical direction, even when cutting the video as an Ultra HD 4K sequence. This allowed me to animate the position of the frames to give the appearance that the camera was craning up throughout the shot.