High-speed video (also known as super-slow motion) can be a valuable tool for recording experiment results. A number of companies manufacture high-speed cameras for scientific and industrial purposes. If you’re building an experiment to fly with Citizens in Space, you probably won’t be running out to buy one of those cameras, though. First, the price is a deterrent, with cameras selling for $25,000 and up. Then, there’s the matter of size. These cameras are fine for laboratory use but too large for the 1U and 2U CubeSat payload volumes we are offering.

Fortunately, consumer electronics have come to the rescue. High-speed video features are now incorporated into a number of small, low-cost consumer cameras. These consumer cameras do not achieve the extremely high frame rates achieved by professional high-speed cameras (thousands or even millions of frames per second), but their small size and low cost makes them well suited for our purposes. And in addition to high-speed video, these consumer cameras offer another useful feature – the ability to shoot high-resolution still images in rapid bursts.

The Point-and-Shoot Option: Casio Exilim

Casio was the first company to add high-speed features to its consumer cameras. [Update: Casio has recently discontinued selling point-and-shoot cameras in the US market. The models described here are still available on the used market. More recent models with similar features are available as unofficial imports on the “gray” market.] These features can be found in Casio’s Exilim line of point-and-shoot cameras, but not all Exilim cameras have the high-speed features. In the current US lineup, there is the EX-ZR100, which lists for $299. The simpler, slightly cheaper EX-ZR10 was recently discontinued in the United States but still sold internationally. The EX-ZR200, EX-ZR300, and EX-ZR1000 are newer models not officially imported into the US. The EX-FC150 is an older, discontinued model. All of these cameras, including the discontinued and international models, are available through Ebay and other online sources. So, you can shop around for the most suitable model and the best price.

Video modes vary slightly from model to model, so it’s important to check the specs before you buy. All of these models will shoot standard and high-definition video at 30 frames per second (fps). High-definition video will be 1080p for current models, 720p for the FC150. High-speed video modes are 120 fps, 240 fps, 480 fps, and 1000 fps. Not all models provide the 120- and 1000-fps modes, however. The ZR100, for example, lacks the 120-fps mode. So, if you need 120 fps, the older FC150 would be a better choice.

Image resolution in high speed mode varies from 640 x 480 pixels (standard VGA resolution) at 120 fps down to 224 × 64 pixels at 1000 fps. In burst mode, these cameras are capable of shooting full-resolution still images (10 megapixels for the FC150, 12 for the ZR10 and ZR100, 16 for the ZR-200) at speeds of up to 30 or 40 images per second (depending on model). The maximum number of frames that can be taken in burst mode depends is limited by the camera’s buffer size. Once the buffer is full, shooting must stop while the camera writes the images to SD card. The FC150, ZR10, and ZR100 can shoot 30 frames in 0.75 seconds before the buffer fills up. The ZR200 can shoot  30 frames in one second before the buffer fills.

Like most point-and-shoot cameras, the Casio Exilim stores photos in JPEG format. JPEG images are stored at a high-quality setting but there are some compression losses. The Exilim also performs in-camera processing (sharpening, saturation and contrast adjustments) on the images. You can control the amount of processing using camera menus but cannot turn it off entirely. The following video demonstrates Exilim image quality at 240, 480, and 1000 fps.

[youtube=http://www.youtube.com/watch?v=_rqE63x-kVQ&w=700]

Another useful feature for citizen-scientists is the excellent close-focusing capability of the Exilim cameras. The  FC150 is capable of macro focusing at distances as close as 3 cm, the ZR10 at 2 cm, and the EX-ZR100 and EX-ZR-200 can go as close as 1 cm. This macro ability allows for imaging within the confines of a small payload box. The camera lens does not include filter threads, however, so it’s not a simple matter to add a closeup lens if you need to get even closer.

The Exilim point-and-shoot cameras are almost a perfect fit for the CubeSat payload form factor. The maximum dimension (width) of the camera slightly exceeds the 10-cm CubeSat dimension. The EX-ZR100, for example, is 10.48 cm. So, it will be necessary to angle the camera or remove the point-and-shoot case to save space. This should not be a problem for a clever hardware hacker.

Casio is not the only point-and-shoot manufacturer to include high-speed video, but it appears that Casio still leads in this feature. The Canon PowerShot SD4500 IS can shoot 320 x 240 pixels at 240 fps, not quite as good as the Exilim FC150 (448 x 336 pixels), ZR100 (432 x 320 pixels), or ZR 200 (512 x 384 pixels). The FujiFilm FinePix 770EXR only manages 320 x 240 pixels at 160 fps and 320 x 112 pixels at 320 fps. The Nikon Coolpix S9100 matches the Exilim’s 640 x 480-pixel resolution at 120 fps but only manages 320 x 240 pixels at 240 fps.

The MIL Option: Nikon 1 J1

Mirrorless interchangeable-lens or MIL cameras, also called electronic-viewfinder interchangeable lens (EVIL) cameras, are a new category of photo equipment that’s emerged in the last few years. Like point-and-shoot cameras, these cameras use LCD displays in place of the mirrors and optical viewfinders found in traditional single-lens reflex (SLR) cameras, thus enabling more compact design. At the same time, these cameras offer more advanced features normally found in SLRs, such as interchangeable lenses and the ability to shoot RAW images in addition to JPEG.

Nikon’s entry in this new category is the Nikon 1 series, which includes some powerful high-speed features.

The Nikon 1 series includes two model lines, designated J and V. The J models include additional features like electronic viewfinders, but the smaller cheaper J models are more interesting to us.

The Nikon 1 J1 was introduced in 2011. The J2 is a minor upgrade introduced late this year. It adds some consumer-oriented features, including a wider range of body colors and some “creative” modes but the sensor is unchanged. The Nikon 1 J2 has a list price of $549 in a one-lens kit. The Nikon 1 J1 kit is available on Ebay for less than $350 (new) or $300 (factory refurbished).

Nikon 1 J1 can capture high-speed video at 400 fps and 1200 fps. At 400 fps, video resolution is 640 x 240 pixels. At 1200 fps, video resolution drops to 320 x 120/pixels. This represents a considerable improvement in resolution over the Casio point-and-shoot.

At 400 fps, the Nikon J1 is capturing 153,600 pixels per frame. At 480 fps, the Casio EX-ZR100 captures only 35,840 pixels per frame. At 1200 fps, the Nikon J1 captures 38,400 pixels per frame. At 1000 fps, the EX-ZR100 captures only 14,336 pixels per frame. Up to 5 seconds of high-speed video can be recorded in a single clip. The following video shows the sort of image quality the J1 can deliver at 400 and 1200 fps.

[youtube=http://www.youtube.com/watch?v=bXiCcvvY_2Q&w=700]

In burst mode, the J1 can record 10-megapixel images at up to 60 frames per second. The buffer will only accommodate 19 JPEG or 13 RAW images, however. So, a burst will only last .217-.317 seconds at that speed.

The 10-30mm kit lens that comes with the camera is capable of close focusing down to 1 cm. It’s also threaded for 40.5 filters. The lens is a little bit larger than most point-and-shoot lenses, though, which will eat into your experiment volume.

The Nikon 1 can be activated by an optional infrared remote control, which provides additional option for activating the camera in flight. Another optional accessory is a waterproof case for underwater photography, which might possibly function as a vacuum-proof case for experiments that are exposed to space. (Some preflight testing required, of course.)

The Sports Video Option: GoPro Hero3 Black Edition

GoPro is a company that manufactures very small video cameras for the action-sports market. The company has just introduced a new model, the Hero3  Black Edition, which has some very powerful imaging modes.

The Hero3 Black Edition will shoot 1080p at up to 60 fps and 720p at 120 fps. That means a 1290 x 720-pixel image at 120 fps, considerably better than the 640 x 480 pixels provided by Casio. It will also shoot 960p (1280 x 960 pixels) at up to 100 fps.

For higher-speed video, it will shoot WVGA resolution (848 x 480 pixels) at 240 fps. By comparison, the Casio EX-ZR100 captures only 432 x 320 pixels at that speed. The Hero3 is providing about three times as many pixels on the screen.

The camera, which retails for $399, can also shoot video at resolutions beyond 1080p: 1440p (1920 x 1440 pixels) at up to 48 fps, 2.7K (2716 x 1524 pixels) at up to 30 fps, 2.7K Cinema (2716 x 1440 pixels) at 24 fps, 4K (3840 x 2160) at up to 15 fps, and 4K Cinema (4096 x 2160 pixels) at 12 fps.

For still photos, it can shoot 5, 7, and 12 megapixel images at up to 30 fps in burst mode. (There’s no indication of how long it can sustain that burst speed.) In continuous mode, it can shoot photos at 3, 5, or 10 frames per second without filling up the buffer. In time-lapse mode, it can take photos at intervals from 0.5 seconds to 60 seconds. Finally, it can shoot simultaneous photos and video: 12-megapixel images while shooting 1440p video at 24 fps and 8-megapixels while shooting 1080p at 30 fps or 720p at 60 fps.

[youtube=http://www.youtube.com/watch?v=xkEr4JGRXFA&w=700]

GoPro cameras have already been tested on high-altitude balloons and sounding rockets. In June 2010, a group of engineers sent a GoPro Hero 2 camera to 80,000 feet on a high-altitude balloon from Davenport, California.

[youtube=http://www.youtube.com/watch?v=UAifzh7_-cg&w=700]

In February 2007, a student project called SQUID (Spinning QUad Ionospheric Deployer) used an HD Hero (an older model) to record the ejection of an experiment from a REXUS sounding rocket at 82 kilometers.

[youtube=http://www.youtube.com/watch?v=HWp4suB60fg&w=700]

Despite its awesome sensor, the Hero3 lacks the zoom lens and macro capabilities of the Casio Exilim and Nikon 1 cameras. The fixed-focal-length, ultra-wide-angle lens is unlikely to be of much use for photographing small experiments close up. Nor is the camera designed to accept interchangeable or add-on lenses. Nevertheless, the sensor is so powerful that some hardware hacking might be in order, even if it involves surgery to the camera itself.

Like the Nikon 1, the Hero3 has a waterproof case and a remote control which might come in useful. Unlike the Nikon, the Hero3 includes these items in the standard package. The GoPro remote control is WiFi rather than infrared. Unlike the Nikon remote, which simply activates the shutter, the GoPro remote can turn the camera on and off and control settings in addition to shutter activation. The GoPro camera can also be controlled by an iPhone or Android app, which brings up the possibility of using a smartphone or iPod as an inflight experiment controller.

Unfortunately, GoPro does not list the Hero3 dimensions in its specifications. The camera appears small enough to fit easily into a CubeSat container, though, with no need for surgery or mounting the camera at an angle. We’ve ordered a Hero3 for evaluation alongside the Exilim and Nikon 1, so we’ll have more details later.

Other Considerations

Choosing a camera is just the first step in developing your imaging system, of course. You’ll also need to think about mounting, control, and lighting.

Mounting the camera may be the easiest part. Most cameras are already designed to be mounted on a tripod, so you could use the tripod threads. Other options include custom brackets or even high-strength velcro. Again, some of the cameras are slightly larger than the 10-cm CubeSat dimension, so you may need to remove or modify the camera case or mount the camera at an angle to fit it within the CubeSat volume. If you mount the camera at an angle, you need to make sure the lens can still see your experiment. A mirror might be useful.

You will need some way to activate and control the imaging system during flight. The simplest approach is to turn the camera on prior to launch and let it record for the duration of the flight. That may not be feasible, however, since some imaging modes have time limits. That’s especially true with high-speed burst modes. You can activate a point-and-shoot camera by providing a mechanical actuator to push the shutter button, or you can take the surgical approach and wire a new connection into the electronics. The Nikon 1 and GoPro cameras have remote controls, which provide additional options.

Lighting is critical for high-speed imaging. High-speed photography necessarily means fast shutter times, so lots of light is needed to get proper exposures. If your experiment is flying in the Lynx’s in-cockpit payload box, you’re going to be in a sealed container so you’ll have to provide your own light. Remember that lights generate heat, and you have to make sure your experiment doesn’t overheat and damage itself or other payloads during flight. High-efficiency LEDs are probably the way to go.

If you’re developing an imaging experiment that flies in the Lynx’s aft-cowling port and looks out through the open hatch, you won’t need to worry about lighting. That’s good because you will plenty of other things, like like vacuum exposure and thermal control, to consider.