I had a bunch of errands to run on Sunday, so again I setup the tripod and pointed it out the window. This time, however, instead of using the Samsung TL350 (a pocketable point and shoot camera), I used my Nikon D80 DSLR tethered to my laptop.
This Nikon doesn't have a built-in intervalometer, a software controller used to set the interval at which the camera will take photos. Instead I used camera control software on the laptop to tell the camera to take a photo every 5 seconds, and to manage the camera's settings such as aperture, shutter speed, image resolution, etc.
I let this run for about five and a half hours, during which time the camera took 2,997 frames. There are a couple challenges with this approach, and the main one is power. The laptop was plugged in, but the camera's battery, while not fully charged when I started, couldn't finish. I happend to walk in the door just as the camera stopped taking pictures and switched the battery. You can buy an AC adapter for a Nikon, but I don't have one.
I did a few things wrong here. First, the camera should be in full manual mode; manual aperture, manual focus and manual shutter speed. This keeps the frames consistent and is also less of a drain on the camera's electronics. I set this camera in aperture priority mode, which selects a shutter speed based on a fixed aperture. As the day grew darker, the shutter stays open longer to compensate. The trouble with this result is you can't really tell its getting darker, and the camera is doing math on every frame which drains the battery more quickly. Further, when I changed the camera battery, the shutter speed reset and because I didn't bother to note the speed, I had to guess. The result is a slight jump in the frames; you'll notice the Empire State Building suddenly goes from gray to orange. Because there are no objects in the background of this scene, the depth of field isn't important so worrying about the aperture is not necessary.
Second, the scene is photographed at a pretty severe angle through two panes of unclean glass, which is why there are vertical streaks around the Empire State Building, and why it looks distorted at night. I'm not willing to climb out the window to clean the glass, and I'm okay with that decision.
Distortions in from the glass can be seen here.
Third, I used an unnecessarily high resolution on the resulting images. Creating an HD video at a minimum requires photos that are 1280 x 720; my photos were 3872 x 2592. The extra resolution is not a bad thing, but it will significantly add to the post-processing time and consume disk space (around 15GB in this case).
When the sequence was complete, I loaded the frames into Aperture to do a batch edit to remove some sensor dust and do some minor color correction. I only retouched by hand a single frame, then batch-applied these changes to all 3,000 frames before exporting. The automated batch process and export took about 2 hours (I went to dinner while this was happening). Finally, I loaded the frames into Quicktime Pro to have them sequenced at 30 frames per second. Rendering the HD video from these frames ran over night. This morning I loaded the video into iMovie to apply the titles, add the music and uploaded the final movie to YouTube. The iMovie and upload process only takes a few minutes.
The result is included below. Shooting a timelapse is easy, but takes time. Its a good background task; set it up, then go do other things. This may sound incredibly time-consuming, but in fact its not. Setting up the camera and starting the process is about 10 minutes, downloading and touching up the images is about 15 minutes and applying titles and uploading is about 15 minutes. Most of the end-to-end time is consumed by the camera taking photos on its own, and then the computer chewing on the results. This would go more quickly with a more powerful computer, but not by much.
5.5 and hours of shooting and 3,000 frames yields about 90 seconds of video at 30 frames per second. I'll try a sunrise next, but I don't think I can sleep with that camera going off every few seconds.