For example, Canon crop sensor cameras … What the are: The kit lens your DSLR or interchangeable lens mirrorless camera came with is probably an example of a standard zoom lens, covering a focal range of around 35-70 mm. A lens’ focal length is defined as the distance between the lens’ optical center and the camera’s image sensor (or film plane) when focused at infinity. The first two letters, “EF”, refer to the type of mount of the lens. A lens’ optical center is the point (usually though not always) within a lens… When it comes to camera gear, the lens is probably one of the most important piece of equipment you can buy. Let’s say you’re shopping around for a lens, and you find an EF 55-200mm f/4.5-5.6 lens. To understand this definition of focal length, we need to define “optical center” as well. What does that mean!? Different camera manufacturers have different focal length multipliers. Download our FREE e-book to get in-depth explanations on prime vs. zoom lenses, anamorphic vs. spherical lenses, wide angle, standard, telephoto and even specialty lenses … Let’s break it down. Let’s take a look at different types of camera lenses explained in more depth. What Are All Those Numbers and Letters? Camera Lenses Explained Every type of camera lens has distinct qualities and visual characteristics that every image-maker should understand. As a result, crop sensor cameras give lenses a longer effective focal length, much like I described my 50mm lens acting like an 80mm lens when I use it on my crop sensor camera body. In many cases, upgrading your lens will probably make a far greater difference …