Pictures in Motion: Timelapses – Post-processing

Time Lapse

The first two parts of this series dealt with capturing the images for a time lapse with different camera types. This easily results in several thousand pictures for a longer clip. There are numerous software tools available for all operating systems to convert these into the final video. Basically, all these applications work in the same way; they differ in functionality, usability, and price. I will present the two approaches I mostly use for creating my videos: the quick-and-easy way using Adobe Photoshop, without further editing of the images, as well as the comprehensive workflow using Adobe Lightroom and LRTimelapse, which offer powerful tools to optimize the outcome.

HOW 2,000 PHOTOS BECOME A MOVIE

Let’s start with the simple case: all of the images are already available in JPEG format, as is the case when capturing time lapses with my old GoPro. If you are using Adobe’s Creative Cloud subscription, you will have Photoshop available in addition to Lightroom. In Photoshop, simply chose File → Open, select the first image, and then check the option for Image sequence. In the next step, Photoshop will ask for a frame rate. Afterwards, you can immediately export the movie in the desired format. If you’re using only Lightroom, many scripts can be found on the internet that will allow you to do basically the same thing.

Open image sequence in Photoshop
Open image sequence (“Bildsequenz”) in Adobe Photoshop CC

Furthermore, there are numerous image editing applications offering this capability. Without having tried them myself, I’d like to mention ImageJ, an open source tool written in Java, and the commercial tool Panolapse. Both are available for MacOS X as well as Windows.

There is one additional option for long-time Apple users, who still have a registration code for the Pro version of the old Quick Time Player 7 in their archives. You can download the last version of QuickTime 7 from the Apple homepage. You cannot buy new license keys for it any longer, but the old ones still work. After activating the Pro version, the option Open image sequence becomes available in the File menu. Just as in Photoshop, select the first file of the sequence, then choose a frame rate. A moment later, you can watch the video. Finally it can be stored as a movie file in Apple’s usual QuickTime format (H.264).

EDITING THE INDIVIDUAL IMAGES

Before the photos get merged into a video, it is a good opportunity to edit them. If you have shot in RAW format, you now have the full editing potential available. This allows for restoring a lot of detail in the highlights and in the shadows. In addition, you can optimize white balance, contrast, and color rendition to your liking.

However, this creates the challenge of editing the pictures consistently, to create a smooth video in the end. Hence, you need an editing tool that enables you to carry over the changes done on one image to the rest of the sequence.

In Adobe Lightroom this works best if you edit a photo from around the middle of the stack, and then synchronize the development settings to all pictures. This works very well, as long as the edits apply equally well to all images. As a part of this process, you should also crop the photos to a 16:9 aspect ratio. After exporting the images as JPEGs with a resolution of either 3840×2160 (4K) or 1920×1080 (Full HD), you can convert the sequence into a video as described above.

WORKFLOW WITH LRTIMELAPSE 4

If you want to make more advanced edits to the image sequence for the time lapse, a usual photo editing software won’t get you very far. The challenge lies in harmonizing the applied changes such that the resulting video doesn’t show any sudden changes in brightness or color, which occur when adjusting the shutter speed or ISO value during dawn. Videos of sunrises or sunsets are hence referred to as the “holy grail” of time-lapse recording.

For such occasions, I recently purchased Gunther Wegner’s software LRTimelapse 4. It works in combination with Adobe Lightroom and offers numerous functions which help to vastly improve the created videos. LRTimelapse is easy to use and offers some very powerful tools to manage adjustments to the original photos, and to handle changes of lighting conditions. LRTimelapse doesn’t modify the pictures itself, it just calculates the necessary adjustments and passes them on to Lightroom as meta data. The actual image processing is then done by Adobe’s Camera RAW engine. The workflow is as follows:

  • Launch LRTimelapse and open the folder with the RAW images for the time lapse. The software imports the files and analyses the brightness gradient. Based on that, it suggests a number of key frames; typically, four to eight. These can be adjusted as needed.
  • Using a special drag & drop button, the image sequence is then imported into Lightroom. Then you can set a pre-defined filter to show only the key frames.
  • These can now be edited to your liking with the full repertoire of Lightroom features. It is recommended to start with the first one, then sync the changes to all subsequent images. Then adjust the second image, if necessary, and again sync the changes to all subsequent images, and so on, until all key frames look the way you want them to. In addition, you should also crop the images to a 16:9 ratio. This will allow you to choose the image section yourself; otherwise, LRTimelapse will select the center part.
  • Once you’re done editing the key frames, save their metadata as files and return to LRTimelapse.
  • Now comes the magic: Based on the key frames, LRTimelapse will automatically calculate the necessary changes to all intermediate images. Thus, smooth transitions for brightness, color, and contrast are created. This will take some time, but you can see the results immediately in a preview clip.
  • LRTimpelapse offers a “deflicker” function for fine-tuning.  This way, I was able to achieve great results even when shooting in aperture priority mode and letting the camera determine shutter speed and ISO value automatically.
  • Store the new settings as metadata files (*.xmp).
  • In Lightroom, loading the updated metadata will apply the calculated changes to all pictures.
  • Finally, the export is started from Lightroom, using the LRTimelapse presets. As a start, all images will again be stored as JPEGs on your local hard drive. When processing 2,700 photos, this can take a couple of hours; at least on my six-year-old laptop. Once this is done, LRTimelaps renders the final video with the chosen settings (resolution, frames per second, video codec etc.). This works rather quickly, and can easily be repeated with different settings from the same JPEG sequence.

Gunther Wegner has a half-hour tutorial video (in English), where he introduces the functions and way of working with LRTimelapse in great detail.

EXAMPLE

The following video shows a sunrise over a period of four hours, with a picture taken every ten seconds. I captured this time lapse with the Canon 760D and the Radian 2. I set the aperture to 2.2 and let the camera choose shutter speed and ISO value automatically. The first images were taken at 5 seconds, ISO 400; the last ones at 1/4,000th second, ISO 100. The Radian 2 panned and triggered the camera.

The photos were edited using Adobe Lightroom and LRTimelapse 4 as described above. This created a video with smooth brightness and color transitions. The last step was adding the music, which is taken from YouTube’s free audio library, using Adobe PremierePro.

The thing that fascinates me even more than dawn itself in this video is the movement of the clouds. This is certainly not my last video of this kind; I will experiment more with capture interval, captured period, location, and weather…


CONCLUSION

Recommendation: The purchase of LRTimelapse was absolutely worthwhile for me, and I recommend it to everyone who considers working seriously with time lapses. A free demo version is available, which is limited to 400 images per sequence, but otherwise offers the full functionality. This will allow you to thoroughly evaluate whether the application meets your needs.

What I’ve learned: I think this series made it clear that capturing time lapses can be a lot of fun. Using the right tools, even difficult lighting situations can be mastered. Thus, small master pieces can be created with reasonable effort – literal “know how”.


LINKS:

Picture Credits: Title Image – Screenshot Adobe Lightroom CC; Open image sequence – Screenshot Adobe Photoshop CC; YouTube Video Sunrise – own images.

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.

Pictures in Motion: Timelapses with a GoPro

Time Lapse

This post is the first part of a mini-series on the topic of time lapses. One of my main motivations for doing photography is to capture scenes in ways that usually elude the naked eye. This includes macro images, freezing fast motion, or visualizing movements in a movie.

To achieve a special effect, you can slow down movements – many current smart phones and action cams offer slow-motion capabilities with up to 120 frames per second. This allows to show action at about 1/5 of the original speed and still have fluent motion. If you want to go even slower, and still have a decent video resolution, you’ll need a dedicated (hence pricey) slow-motion camera.

The opposite effect can be realized in a much simpler way: time lapses are suitable to visualize motion patterns that move too slow to grasp them in their entirety by simply looking at them. All you need for a time lapse is a digital camera with the capability to take photos at fixed time intervals, as well as a software tool that turns the individual images into a movie. Numerous such tools can be found on the internet. The camera doesn’t even need to be a high-end model; a 10-megapixel camera can already render a 4K video.

This first part of this series will cover the process from capturing the images to creating the movie using a GoPro camera and its proprietary software.

IDEA & LOCATION

The Railway Museum Darmstadt-Kranichstein is definitely one of the locations where I have taken the most pictures, and over the longest period of time. I don’t primarily focus on the various engines in the exhibition, but rather try to capture the hustle and bustle during the events. This is particularly true for our biggest event, the “Railworld Days”, which take place every year on a four-day weekend around the mid of May. I put the focus of my images on the audience in the first place, while the moving engines and such are shown as what is drawing the visitors’ attention.

However, these photos always captured just a single moment in time: Since I am working in the museum myself, I am bound to my tasks in the exhibits during the events. Thus, I mostly miss what is happening outside – except for breaks, which I use for taking pictures as well. But I was always curious about what happened “out there” during the entire day. Hence, I mounted my camera right in the middle of the action. It would be rather boring to watch the recording of an eight-hour day in real time, and so I had the idea to capture time lapses.

GOPRO CAMERA & SOFTWARE

Many years ago, I bought a GoPro Hero 3+ Black Edition action camera, to capture photos and videos from perspectives that are not – at least not easily – accessible with a big camera. In addition to various video modes, all GoPros offer a time lapse mode, which takes a photo every few seconds. The time interval can be set between 0.5 and 60 seconds. Which interval is the best depends on what scene you want to capture, i.e. what is moving, and how fast it is moving.

Once started, the camera keeps on recording until either stopped, the battery runs out, or the memory card is full. To avoid the latter, I bought a 64 GB micro-SD card. I used two different power supplies: the internal battery, in combination with the additional snap-on battery that is available for the GoPro 3+. This lasts for about 3-4 hours. To capture an entire day, I set up external power via a power adapter and a USB cable.

RECORDING

As with everything in photography, a time laps requires a suitable (interesting) subject. An additional challenge is that the scene should change over time: clouds in the sky, traffic on a lively intersection, or – at the railway museum – the turntable in front of the roundhouse. Next, a good location for the camera is needed, as well as the necessary adapters to mount it securely and solidly. I checked the orientation of the camera using the freely available Smartphone app, and also started the recording this way.

I usually work with a two-second time interval at the museum. In the course of an entire day, this results in 14,400 pictures being taken. Turned into a video at 30 frames per second, eight hours become eight minutes.

POST-PROCESSING

My old GoPro is capable of taking JPEG images only, which limits the post-processing possibilities; especially considering that any changes would have to be synchronized to all images. Given the huge number of files, this poses high demands on the hardware and software alike. So how can all these single photos be turned into a video? The simplest solution is using the “GoPro Studio” software that comes with the camera.

GoPro Studio
Screenshot GoPro Studio (v2.5.12) – Import and edit timelapse video

In the first step, you select the folder on the hard drive that contains the files copied from the camera. The software automatically creates a preview video from the images. Then you chose the desired options; primarily, how many frames per seconds the video shall have, and whether the fish-eye effect from the GoPro’s ultra-wide angle lens shall be removed or not. This makes sense especially if there are many straight lines in the image, but it can also lead to strong distortions in the corners of the frame. Finally, the tool converts everything into a final video, which can then be exported in the desired format.

EXAMPLE

The following video was created three years ago, using the GoPro and the included software as described above. The time interval was set to two seconds, so over the course of eight hours, 14,400 photos were taken:

This clip doesn’t have any sound, because it has been assembled from individual images. It can be used as-is, or combined with other building blocks to create a diversified movie – with sound, of course. The GoPro software offers some built-in video authoring capabilities, but I have never used them. Earlier, I used Apple’s iMovie software to create my movies. Now, I am using Adobe’s Premiere Pro CC. However, I will not cover video editing in this post.

ALTERNATIVES AND LIMITATIONS

Thus, it shouldn’t go unnoted that in the meantime, many very affordable alternatives for the original GoPro cameras are available. Of course, there are some differences in terms of quality of the resulting photos and videos, at least when comparing them to the top-of-the-line model. Whether that is worth the additional price depends on your personal preference.

Many modern smart phones also offer a time lapse function – either directly in the built-in camera app, or by means of third-party apps. For my use case, however, this is not a viable alternative: smart phones are much more susceptible to environmental conditions (direct sunlight, rain), the storage capacity usually is as limited as the battery capacity – and who wants to mount their smart phone with all the data on it unguarded somewhere in the event area?

Either way, there are limitations. Foremost, you are bound to the fixed focal length of the camera, which contains an extreme wide-angle (fish-eye) lens. That is not always what you need. In addition, the small camera tends to have problems with high contrasts – on a bright sunny day, either highlights such as clouds end up as pure white blobs without any details, or the shadows drown in black. In addition, the automatic white balance and the auto-exposure function sometimes create strange artefacts, for instance when clouds move across the sun and cause the brightness and color of the light to change.

GoPro cameras offer an advanced capturing mode, called “ProTune”. It allows to set a fixed white balance and creates images with reduced contrast to offer more leeway for post-processing. However, I never achieved satisfactory results using this for time lapses. This may well be because I lack the necessary experience with color grading and look-up tables. Current GoPro models, such as the Hero 5, can capture photos in RAW format. If your camera supports this, you should definitely use it!

OUTLOOK

The next part of this series will cover capturing time lapses with a DSLR or mirrorless camera, as well as adding some additional motion to the video. Finally, the third part will deal with the post-processing; in particular, how to take full benefit of the RAW images to create a high-quality video with reasonable effort.


CONCLUSION

Recommendation: Time lapses can be created quickly and easily with the GoPro, and the results are remarkable. This approach offers several advantages: the camera is small, light-weight, unobtrusive and can be mounted almost anywhere. It works completely silent and lasts many hours when using the additional battery. The conversion of the individual pictures into a final video is just a matter of a few clicks using the included GoPro Studio software. All in all, lots of fun for little effort!

What I’ve learned: Time lapses opened a new way for me to use photography to capture motion patterns. The fact that you can leave the camera to “do its thing” once it has been set up, and that you can tend to other things in the meantime, is an additional bonus.


LINKS

 Picture Credits: Title Image – Screenshot Adobe Lightroom CC

YouTube Recommendation: Marc Levoy – Lectures on Digital Photography

Marc Levoy - Lectures on Digital Photography

When you start looking into the theory of photography, you soon realise that it is quite easy to become lost in detail. The exposure triangle alone just doesn’t do it. How does the image get to the sensor in the first place? How does the camera see colours? How do we see them? Where does image noise come from? You can either search for the answers to any of these questions individually – or you grab the comprehensive package provided by Marc Levoy.

SUMMARY

Marc Levoy is a Professor Emeritus of Computer Science at Stanford and now works for Google. From 2009 to 2014, he taught a University course titled “how cameras work, and how to take good pictures using them”. In the spring of 2016, he gave an adapted version of this course at Google, which thankfully was recorded and made available online. 18 lectures, altogether more than 22 hours of video material. This is the course description given on the homepage:

An introduction to the scientific, artistic, and computing aspects of digital photography. Topics include lenses and optics, light and sensors, optical effects in nature, perspective and depth of field, sampling and noise, the camera as a computing platform, image processing and editing, and computational photography. We will also survey the history of photography, look at the work of famous photographers, and talk about composing strong photographs.

The lectures are easy to follow; the image and audio quality is very good. Even more important, he does not lose himself in gobbledegook, even when going deep into the finer details. He never loses the golden thread, and that is what makes the entire package so interesting.

The lecture’s Homepage does not only provide the links to the 18 YouTube videos, it also runs all applets used in the lectures, including instructions, as well as all of the assignments if you want to give it a try yourself!


CONCLUSION

Recommendation: This is a must-see!

What I’ve learned: A lot 🙂 In particular, it helped me understand a lot of technical background as well as explaining contexts which are easily missed when just looking into individual aspects. Of course you can use the course schedule to pick out the topics you’re most interested it, but I strongly recommend taking the time to watch the entire course over time.


LINKS

Wishing you interesting hours,
– Jochen =8-)

Title image: Screenshot from Homepage

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