Pictures in Motion: Timelapses with a DSLR/DSLM

Time Lapse

This is the second part of a mini-series on the topic of time lapse photography. The first part introduced the creation of time-lapse videos with a GoPro (or similar action camera). This renders quite good results with a reasonable amount of effort. There are two starting points to further improve the outcome: free choice of focal length, and manual control of the exposure.

POTENTIAL FOR IMPROVEMENT

As mentioned above, the most obvious advantage when using an interchangeable lens camera compared to the GoPro is the ability to freely chose the focal length. This enables different perspectives, as you can emphasize certain details of a scene. The longer the focal length, the more obvious camera shake will be, e.g. because the wind pushes against the lens. This must then be stabilized in post-processing to avoid jitter in the video. Hence it is important to mount the camera in a very stable way.

Furthermore, the camera’s manual mode allows for full control over the exposure of the images – i.e., shutter speed, aperture, ISO, and white balance. If no drastic change in lighting conditions is anticipated during the recording time, it is highly recommended to set and fix all these values manually. This guarantees a consistent appearance of the photos and avoids strange effects the camera’s automatic mode might cause, e.g. when a cloud covers the sun and the scenery consequently becomes darker and bluer. It is also mandatory to manually focus on the most important object in the scene, to avoid any unintended re-focusing when something moves through the frame.

To take full advantage of the image quality, you should of course shoot in RAW. As a result, you’ll have to keep an eye on the amount of data generated, much more so than with the GoPro. A single RAW file from my Canon 760D is up to 30 MB in size. A time lapse of one and a half hours with a capture interval of two seconds creates 2,700 images – about 80 GB of data! Consequently, I have bought a 128 GB SD card for such occasions. The camera’s battery also has to last sufficiently long, hence I am using a battery grip than can hold two batteries for longer recordings.

An additional degree of freedom is offered by the use of filters. Whether you’re using an action camera or a DSLR, when taking pictures on a bright day, the shutter speed will be very fast – around 1/1,000th of a second. This causes the final video to look very “jumpy”, because moving persons or object suddenly appear in a different location, as can be seen clearly in the example video in the first part of this series. To achieve a fluid motion in videos, the shutter speed is typically set to half of the frames per second – i.e. 1/60th for 30 fps. This is where so-called grey filters or neutral density (ND) filters come into play: they allow for slowing down the shutter speed without over-exposing the image.

I have used a 10-stop (1,000×) ND filter, so I could work with a shutter speed of half a second. In combination with the Tokina 11-20 mm Ultra-wide angle, I have used the following settings: ISO 200 | 16 mm | ƒ/4.0 | ½ sec. This will blur the motion in each image. In combination with a time interval of two seconds, this creates a smooth flow. You will find the final video for comparison at the end of this post.

Motion Blur
Motion Blur due to a shutter speed of half of a second when using a neutral density filter

In general, polarizing filters can be used as well, but with limitations: Since the effect of a polarizing filter depends on the angle between the camera and the sun, the magnitude of the effect will change if the sun moves significantly during the recording. This can hardly be compensated in post-processing.

Unlike the GoPro, my 760D doesn’t have a built-in intervalometer. This means that the impulse to take a photo every x seconds must be given externally. The least expensive option is using a programmable cable remote. Usable models can be found on the internet for as little as 20 Euros for almost every camera. Another option is using a smartphone app. Basically every camera with built-in WiFi or Bluetooth nowadays comes with a matching app, which usually supports time lapses as well as many other functions.

In addition to technically better images, I also wanted to add another component to make my time lapses more interesting: moving the camera itself. This requires very precise control to create a smooth motion in the final video. Numerous devices are available for this purpose, which control the movement of the camera as well as the synchronized shutter control.

ALPINE LABS RADIAN 2

I became aware of Alpine Labs’ Radian 2 via a crowdfunding campaign. The device, which looks like a simple black can on the outside, packs a lot on the inside: a motor to move the camera, a sophisticated controller for the camera, and a large battery that will last for many time lapse recordings. It is operated via Bluetooth using the matching smartphone app. Basically it enables time lapses with camera panning: over a set period of time, the camera will be rotated by the chosen angle (horizontally or vertically), while taking a picture every x seconds. The Radian will always take a short pause between moving and shooting to avoid blur from camera shake.

Time-Lapse Setup
Time-Lapse Setup: Canon 760D with battery grip, Alpine Labs Radian 2 and iPhone with Radian App

The Radian didn’t have any problems at all when panning horizontally with the quite heavy combination of camera, battery grip, and Tokina lens (total weight: almost 4 lbs). However, that proved to be too much for a vertical tilt. I will test that again with a lighter setup.

Aside from that, the Radian can vary the shooting parameters over time in several ways. When taking a time lapse during dusk or dawn, it can adjust the exposure of the images (“exposure ramping”). It can also vary the time interval at which images are taken over the recording time, so that the speed of the final video changes (“speed ramping”).

All in all, it is a very versatile and easy to operate device, that brings a lot of variety to your time lapses. Of course, you can use the Radian also to pan the GoPro – however, this lacks the synchronization with the camera and hence many of the advanced capabilities, because the GoPro cannot be remote-controlled in the same way. The Radian 2, as I have it, is currently sold out at Alpine Labs. If and when it will become available again is unclear. However, similar devices are available from various manufacturers.

EXAMPLE

The following video shows a period of about one and a half hours. As described above, the pictures were taken with the Canon 760D, mounted on the Radian 2, and with an ND filter on the lens. A picture was taken every two seconds, with a shutter speed of half a second. The resulting motion blur makes the movements in the video appear much more fluid; the people no longer jerkily jump around. The panning motion of the camera adds additional movement. What fascinates me the most in this video, however, is the movement of the clouds on that day.

OUTLOOK

The next part of this series will cover the post-processing: how do you optimize the captured images, and how do you convert the individual pictures into a movie? There are countless ways for processing and conversion of the data. I will present the approaches and software I mostly use.


CONCLUSION

Recommendation: Concerning image quality, there is a vast difference between photos taken with a GoPro, and those taken with a bigger camera. On the other hand, the necessary equipment is bulkier and heavier (and more expensive). Depending on the occasion, you will have to balance to pros and cons for each. Whenever feasible, I highly recommend using a DSLR or DSLM, to have full control over the outcome of the images and the maximum creative leeway for post-processing.

What I’ve learned: It is important to choose and fix all relevant setting manually: shutter speed, aperture, ISO, white balance, focus point. This ensures a consistent appearance of the images and avoids the strange side-effects from automatic adjustments. When capturing fast action, such as passing cars for instance, the resulting video will look much more pleasant when using an ND filter to slow down the shutter speed and thus blur the motion.


LINKS

Picture Credits: Title Image – Screenshot Adobe Lightroom CC; all other pictures – own images.

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