Selecting a camera
Making a movie

Introduction
The availability of relatively inexpensive digital cameras has made it affordable and relatively easy to make time-lapse movies. For example, it is now possible to make decent time-lapse movies using an inexpensive web cam and some free or almost free ("shareware") software. Of course, it is also possible to make high-quality movies with more expensive consumer or professional digital still cameras. Because digital cameras are continuously being updated and replaced by new models, it is difficult to recommend specific makes and models. Rather than trying to recommend a particular camera, the information provided here may provide some of the basic features that make a camera suitable for making time-lapse movies.

Being a plant biologist, we will use plants as our subject of choice but time-lapse imaging is also great for making movies of all kinds of things like the flow of people in public places or clouds drifting across the sky. In addition, many of the same techniques can be used to make stop-action movies.
Before continuing, if you are not a patient person, you do not have time to read the manual for your camera, you fear computers, or you do not like to tinker with things, you probably do not want to get into time-lapse imaging.

Selecting a Camera – A critical step to time-lapse imaging is, of course, finding a camera with time-lapse capability. There are several things to consider before deciding on a particular camera. In general, it is probably best to look for the highest resolution camera and best lens system you are willing to pay for. Even if your immediate needs do not require high resolution images, once you get started, there is a good chance you will want better equipment after a while. As with still images, you can always downsize a high resolution movie but increasing the size of low resolution movie usually doesn't work very well. Capturing movies at a higher resolution than your viewing device is not going to make them look better. However, it depends on what you want to use your movies for.

Computer-controlled or free-standing camera? There are many more camera options when it comes to using computer-controlled systems. For example, many of the canon cameras, including their digital SLRs come with software that provides time-lapse capability. However, computer-controlled systems can get expensive, especially if you don’t have a computer that is available - depending on the software you use, you may not be able to use the computer while it is controlling the camera. In addition, being tethered to a computer can limit the locations where you can set up for extended periods of time.

Free-standing cameras provide a great deal of flexibility in terms of where you can set up but there are relatively few digital cameras available that provide time-lapse capabilities. Many people think that a camcorder of some sort (digital or otherwise) would be best but very few have time-lapse capabilities (the revolving tape heads will wear out tapes during extended intervals). Indeed, most camcorders automatically shut off after 2 to 3 minutes to protect the tape, making them nearly impossible to use for time-lapse recording. However, many of the fire-wire capable digital video recorders that can also capture still images to memory cards can be used for time-lapse using computer-control. For example, we have had success using Canon and Sony DV cameras with the shareware program BTV Pro.

If your demands for image quality and resolution are not high, some of the inexpensive web cams will do a reasonably good job but few of them come with software that allows time-lapse capture. Fortunately, there are a number of freeware or shareware programs available that provide time-lapse functionality for various web cams. We have several old models of the QuickCam camera, which came with excellent time-lapse software. In spite of their low quality lens, with a little patience it is possible to make decent movies (i.e., see Arabidopsis germination). With more firewire web cams becoming available and a shareware program like BTV, it is quite easy to make time-lapse movies. We have used BTV ($30 shareware) to make time-lapse movies with the Pyro Firewire web cam (unfortunately, the image quality of the Pyro camera is worse than our 7 year-old QuickCam). Although the web cams typically have low quality lenses and limited resolution, they work well for some uses and they are quite inexpensive, assuming you already have a computer. If you are interested in using a web cam for infrared imaging, you can find some information that may be helpful here (QuickCam IR modifications).

Due to their superior lenses and resolution, consumer-grade digital still cameras are an excellent choice. Some models can do time-lapse imaging without being tethered to a computer allowing you to make movies in tight locations. For example, the Konica Minolta Dimage A2 can be programmed from its menu to capture up to 240 images at intervals from 30 s to sixty minutes. Several of the new Canon and Nikon cameras also provide time-lapse options. Given the rate at which new cameras appear, selecting a camera that will work for your situation will require some research. To learn about the capabilities of many of the currently available digital-still cameras, you can try the following digital camera web sites:
http://www.dpreview.com/
http://www.steves-digicams.com/
http://www.imaging-resource.com/
The reviews on these sites sometimes fail to mention time-lapse functionality so you may also need to look at the manufactures specifications.

We have used Kodak DC290 and Minolta Dimage 7 cameras for many movies. These are both discontinued models but they still work fine (the DC290 has recorded over 60,000 images and the D7 over 30,000). When we need to use infrared imaging, we use modified QuickCam cameras or infrared-sensitive B&W video cameras with PC capture cards. Instructions for modifying a color QuickCam for infrared use can be found here (QuickCam modifications). The instructions are for an old model and the details may not apply to the newer models but the general ideas should still apply. (note: Digital Video camcorders that have NightShot mode and still image capability can also work for IR imaging)

Making a movie – Before setting out to make a time-lapse movie, you should become familiar with your subject. For example, to make a movie of a particular plant, it is important to know how to grow the plant, how fast it grows, what stage of growth or response you want to capture. Having a good understanding for the time required for the process of interest is important when making critical decisions the time interval to use between images. For example, if you want to film the opening of a particular flower, you need to determine when and how quickly flowers of that species open. In the case of morning glories, the flowers may open between 5 and 6 am and they are fully open by 8 am. To get a smooth movie of the opening process, intervals of 1 to 5 min should work. If you don’t want to get up at 5 am, you would need to set up your camera the night before. Using artificial lights can affect the way a plant or flower grows so some experimenting is usually required before getting adequate results. Most of the movies on the Plants-In-Motion site required several attempts before we felt they were adequate for their intended purpose. If it takes a weeks for a particular seed to germinate, it may take a few tries (i.e., a few weeks) before you get a good movie.

One strategy we use when working with a new plant is to set up a camera using 30 min intervals and let it capture a few days worth of growth. Upon examining the image series, it is usually possible to determine an appropriate time-interval needed to capture the process of interest. With camera and computer memory becoming cheaper all the time, we typically aim for the shortest intervals practical. It is always important to keep in mind that the higher the resolution and the more images, the larger the movie file. For example, a movie made from 500 images captured at an image resolution of 720 x 480 pixels may be around 80 MB. Movies of that size are great for computer playback, CD or DVD. An 80 MB movie on the web is not such a good thing. Reducing such a movie to 320x240 and using video compression can get the movie to a few MB, which is much more reasonable for the web delivery.

We always try to use manual focus and exposure settings. Autofocus can get confused as the subject grows and changes, which could result in focusing on the wrong object. If you use fluorescent lights, you should use a shutter speed of 1/15 s or longer to avoid the 60 hertz flicker of the fluorescent bulbs. Make sure you use the correct white balance for the light conditions you are using. Like the autofocus and autoexposure options, auto white balance doesn't always work the way it should. If you are shooting outdoors, it might be necessary to use auto exposure since the light levels can change quite a bit. Like regular photography, you will need to experiment with your camera, subjects and conditions until you get results you like.

Building movies from still images – Some capture software (like BTV) and some cameras can automatically make movies as the images are captured. Others simply save the images in a directory (folder). We usually do not let the software or camera make movies directly since we sometime use still images for other things. Fortunately, QuickTime Pro ($30 registration of the free player will let you activate the Pro features) will take a folder of images and make a movie from them as long as the images are named in sequential numerical order. Most time-lapse capable cameras use the time and date to name the images so they are automatically sequentially numbered. Depending on how many images were captured, it usually only takes a few seconds to import them into a QuickTime movie. There are some freeware and shareware programs that claim to do the same thing but we haven’t tried any of them.