Tiny Cameras, Huge Challenges

2013 saw a growing trend towards smaller cameras.

As the cellphone industry has driven the development of smaller and more efficient image sensors, the surveillance industry has quickly latched on to the new technology. With multiple manufacturers releasing miniature cameras this year, I had to wonder: Is smaller really better?

Click here to view Figure 1.

As cellphone cameras continue to slowly replace point-and-shoots, consumer camera manufacturers are fleeing to higher ground. Nikon, Sony, and Canon have all begun releasing point-and-shoots with larger format image sensors. These new large-format point-and-shoots are typically heavier and bulkier than their predecessors but, in turn, offer near professional-level image quality, something cellphone cameras do not.

To understand why smaller image sensors result in lower image quality, one must first understand how image sensors capture light. Image sensors are made up of millions of light-sensitive spots called “photosites.” These photosites collect the light after it passes through the camera lens. The bigger the photosites, the more light can be captured.

Poor low-light performance

On smaller image sensors, these photosites are so tiny that they require an abundance of light in order to perform well. As light levels drop off, smaller image sensors are unable to collect enough light, creating images that are noisy and lack contrast.

Unfortunately, this problem will not soon be overcome. While image sensors may be getting smaller, the photons they collect will always remain the same.

Limiting lenses

With smaller image sensors come smaller lenses. These lenses are typically prime (or fixed) lenses and are usually of the wide-angle variety. Condensing so much information is a tricky job for these little lenses, and, consequently, image quality is often sacrificed. These tiny wide-angle lenses are prone to image quality issues like chromatic aberrations, loss of contrast, and vignetting. While vignetting might look impressive in an episode of Top Gear, it doesn’t have the same appeal in video surveillance.

Not all hope is lost though. Smaller image sensors do have their advantages. Aside from creating more discreet cameras, these sensors are extremely cost effective, as are the lenses that accompany them. With the added benefit, discreet megapixel cameras still perform significantly better than their analog counterparts. In addition, if you are one of those people who lie awake at night worrying about the polar ice caps, you will be happy to know smaller image sensors consume less energy.

Discreet cameras have their challenges. They will never boast the best image quality, and they are certainly not the right choice for every application. However, smaller cameras will always have a place in the surveillance industry, as long as that place is well lit.

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