One of the first things that catches the eye when comparing different models of cameratraps, is the number of megapixels; thinking 'the more megapixels, the better the image'. Manufacturers respond to this by interpolating the number of megapixels (see box below) and advertising these interpolated megapixel values. However, the 'real' resolution is hardly ever reported, while this actually says a lot more about the quality of the image.
A similar marketing trick is applied to the video resolution. Nowadays there are cameratraps available with a 4K Ultra HD video resolution. This sounds very promising, but in reality this resolution is often achieved with a frame rate of 15 frames per second (fps). By contrast, Full HD cameras usually hold a frame rate of 30 or even 60 fps. The number of frames per second says a lot more about the quality of the video.
A higher photo- or video resolution is therefore not always equal to better images. The best advice is to base your opinion on actual images that are derived from the field.
Interpolation means that new data points are extracted within the range of a set of known discrete data points, assuming a certain relation between those points. More specifically, in the case of cameratraps and megapixels, this means that the software in the camera tries to turn one pixel into four pixels, for example. The color of these four new pixels is extracted on the basis of the color of one single pixel. Although there are methods of good interpolation, it is a myth that interpolation increases the quality of your image. After all, interpolation remains an adjustment of the real image acquired by the image sensor. In fact, interpolation is often accompanied by more digital noise and color shift. Also, it only leads to more data storage and battery consumption.
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Adjustable resolution
In many cameratraps, the resolution is adjustable for both photo and video. By adjusting the resolution to your desired target, you can work more efficiently with the battery life and storage capacity of your cameratrap. A resolution as high as possible can be superfluous. For example, when you just want to detect the presence of an easily recognizable species. By now you are also aware of the fact that a higher resolution does not necessarily result in sharper and better images (see text above). In fact, a higher resolution often has a slower shutter speed, which may result in a blurry picture of a moving animall. A higher image resolution can be especially useful when observing small, less easily recognizable animal species.
