Modern high-definition camcorders really are remarkable devices. They are lightweight, easy to use, and can offer truly amazing picture quality. However, if there is one aspect of camcorder performance which can still sometimes be a let-down, it is the image quality they produce in lower light conditions.
The problem stems from the fact that what we want from a camcorder is a level of versatility approaching that of the human eye. While our eyes are the product of billions of years of evolution, camcorders have to make do with technology only developed over the last few decades.
In recent years, camcorder development has resulted in some significant advances in this area. The result is that there are now some devices on the market which address the low-light problem in a number of innovative ways.
The Low-Light Problem
Camcorder owners upgrading their digital video machines to newer high-definition models were initially wowed by the stunning picture quality of their new devices. However, they also quickly discovered that the high-definition camcorders have a significant weakness in comparison to the outgoing technology. The light sensors which are able to capture the wonderful detail of a high definition image are less than impressive when employed in conditions of lower light. Manufacturers have been quick to address the problem and high-definition camcorders are now becoming available which offer significantly better low-light performance.
What to Look for in a Low-Light Camcorder
For a camcorder to operate well in low-light conditions, it needs to be able to get the maximum amount of light into the machine and then to make the most effective use of that light. Comparing the low-light capabilities of different camcorders is fairly straightforward. Within the spec sheet, there is usually enough relevant information to indicate how well the device will perform in low light.
The most important specification when attempting to assess the low-light capabilities of a camcorder is the device's lux rating. This defines the lowest light level at which the camcorder is capable of giving an acceptable image. Lux is a measure of available light, which means that for the purposes of comparing camcorders, a lower lux rating means the camcorder will perform better in low-light conditions.
Minimum lux is an important consideration for camcorders. Unlike still cameras, which can vary their exposure time in response to lower light levels, exposure is fixed by the camcorder's frame rate. If a higher lux rated camcorder is purchased for use in low light, no other features of the device will be able to adequately compensate for the higher lux rating.
After lux rating, the next most important indication of a camcorder's potential as a low-light device is its lens size. Larger lenses make it possible to initially gather more light for the machine to process. Camcorders with average sized lenses are more likely to struggle when used in low-light conditions no matter how good the technology housed inside.
The camcorder aperture controls the amount of light that is able to enter the machine. Models which have a greater aperture size are able to process more of the available light. Generally, camcorders with larger lenses also tend to have larger aperture sizes. When comparing two devices, where all else is equal, preference should be given to the machine with the larger aperture dimension.
An imager is basically a camera on a microchip and is located directly behind the lens. There are two basic types of camcorder imager available. These are known as CMOS (complementary metal oxide semiconductor) and CCD (charge coupled device). Both imagers convert light into an electronic signal, but they do so in slightly different ways.
CMOS imaging chips were originally developed for use in mobile phones, primarily due to their low power consumption. Until recently, CCD imagers were the preferred choice of camcorders manufacturers due to their superior image quality. However, with the might of mobile phone manufacturers behind it, CMOS imaging technology has now started to emerge as the imager of choice for the majority of camcorder manufacturers.
In the spec sheet, imagers are usually described by both their size and the number of pixels that are on board. Of the two specifications, imager size is the most important consideration to anyone looking for a camcorder with good low-light ability. The larger the imager size, the more light the camcorder is able to collect and process. Therefore, preference should be given to camcorders which have larger imagers, all else being equal.
Camcorders which have an optical zoom facility will work better than those which rely solely on a digital zoom. When an optical zoom is used, the whole of the imager continues to be employed in creating the image. When a camcorder is digitally zoomed it concentrates on a smaller area of the imager to produce this effect. In low-light conditions this means some of the light getting to the imager is wasted. By comparison, all the useable light that falls onto the imager of a device which has an optical zoom is available to be processed.
If the camera is intended primarily for close range low-light filming, the solution may be to select a camcorder which has a good-quality video lamp facility.
On board camcorder video lamps tend to be relatively low power affairs, useful only in marginal light conditions or at very close range. More powerful external devices can be mounted to most camcorders and offer a far superior field of light, up to a distance of about two metres.
The best external camcorder video lights are multiple LED models, which are capable of producing many hours of flicker free light from their own internal power source. As LED light can be rather stark, it is worth looking for models which include filters. Video lamp filters can be used to both soften and warm the output light.
Some camcorders allow the operator to lower the frame rate in low-light conditions. This increases the amount of light that can enter the camera for each frame, allowing the imager more opportunity to produce a reasonable quality image.
When choosing a camcorder for filming in low-light conditions, the single most significant attribute to consider is the device's lux rating. Subordinate to this, but still meriting analysis, are the dimensions of the lens, aperture and imager. Some camcorders offer features allowing them to function better in low-light conditions, such as adjustable frame rates and optical zooming. Camcorders which offer the facility to illuminate the subject, either internally or externally, with a video lamp may also provide a solution for filming at close range.