Lenses are always identified by their focal length. It’s not just a physical measurement, it’s an indication of the type of lens it is, for example, a wideangle lens, standard lens, telephoto and so on. In other words, the focal length of the lens gives you an indication of its angle of view. Or at […]
Effective focal length
The angle of view of a lens changes according to the size of the sensor in the camera. A smaller sensor captures a narrower angle of view and makes it look as if the lens has a longer focal length. So in addition to the actual focal length, the manufacturers will usually quote the 'effective' focal length too.
Lens types and what they’re used for
The advantage of interchangeable lens cameras like DSLRs and mirrorless cameras is that you can change lenses for different kinds of photography. There are many different types of lenses, often with specific names. Lenses are usually characterised or grouped by their focal length. It might be more useful to use their angle of view instead, […]
Camera shake and how to avoid it
Camera shake is blur caused by camera movement during the exposure. It happens with indoor shots or outdoor shots in poor lighting or at night, when the low light levels mean the camera uses a longer exposure and hence a slower shutter speed. The slower the shutter speed, the more likely it is the camera […]
Sensor size and why it matters
In the days of film, it was well understood that the bigger the negative, the better the quality of the picture. The same is true with digital cameras, only here the ‘negative’ is the sensor. The larger the sensor size, the better (generally) the picture quality. Megapixels do confuse the issue somewhat because you can […]