Can the Samsung Camcorders Shoot Night Vision?by Richard Gaughan
Anyone who's seen any movies of international intrigue produced in the last few years has been exposed to images of spies, thieves, or police using night vision cameras. Perhaps those movie scenes have inspired you to see if you can modify your Samsung camcorder to make your own night vision camera. The answer depends on both what you consider "night vision" and how much work you're willing to put in.
There are a couple of different common technologies at the heart of today's camcorders. The image sensor – the part of the camera that converts a light pattern to electronic signals – is either a charge-coupled device or a complementary metal-oxide semiconductor device. Samsung camcorders use CMOS detectors. CMOS detectors are built out of silicon, in the same way your computer chips are built. In addition to having areas set aside for collecting light, CMOS detectors also have circuits built onto their surfaces.
The low light performance of a camcorder is primarily limited by the sensitivity of the image sensor. The Samsung CMOS image sensor is modified to increase its sensitivity by flipping it over so it is back-side illuminated. That means that the extra circuitry built on top of the image sensor ends up on the bottom, where it won't block any light. With this design, each pixel picks up as much light as possible. In addition, silicon CMOS detectors not only sense visible light, but they are also sensitive to near-infrared light as well – wavelengths that are invisible to humans.
There are many different definitions of "night vision." The most high-tech version is where a camera senses the invisible infrared radiation emitted by warm objects, such as people or cars. Those wavelengths are far away from the near-infrared wavelengths the Samsung camcorder can detect. Another definition of night vision applies to the technique of shining a near-infrared light source at a scene and using an image sensor to collect the reflected light. Theoretically, the Samsung camcorder could do this, but only with extensive modifications. One more definition of night vision encompasses techniques to detect very low light levels. The Samsung camera could possibly be considered a low light level imager – but not a very capable one.
Samsung Night Vision
The Samsung sensor is both back-side illuminated and thinned as well, which means some extra silicon has been shaved from the sensor, reducing the noise. Samsung claims their CMOS sensor is "twice as sensitive," leading to better low light performance. They don't say what they're using for the "twice as sensitive" comparison, nor do they quote a specific minimum illumination level. But that's it for a built-in night vision capability: the low light imaging of the camcorder enabled by the CMOS design.
Modifying for NIR Night Vision
The CMOS sensor can see near-infrared wavelengths, but during normal operation that introduces noise. For that reason, there's a blocking filter inside the camera that prevents near-infrared light from reaching the sensor. If you're really serious about modifying your camera for night vision, you can remove the front lens and pull out the infrared blocking filter – voiding your warranty in the process – and then replace the front lens. After that, you can buy yourself a near-infrared flashlight or an add-on near-infrared illuminator accessory to attach to the camera. When you shine that light on the scene, your camera will pick up the reflected light, even though the scene looks completely dark to the eye.
- photo_camera Ethan Miller/Getty Images News/Getty Images