Understanding Basic Lens Anatomy and Terminology

The lens is the eye through which a camera sees. No matter what kind of camera you use, the lens is one of the single most important investments you will make. So in the spirit making wise decisions and minimizing buyer’s remorse the gear-savvy photographer will make it a point to understand the basics of lens anatomy. Not only with understanding the basic ins and outs of your lens make you a better technical shooter, but it will also enable you to squeeze every last drop of performance from whatever glass you happen to be using.

Without a doubt the numbers, markings, and terms often associated with camera lenses can be confusing. The good news is that they don’t have to be! Generally speaking, all those numbers and symbols are actually quite simple to understand. Let’s begin with some terms and names of common lens components you will likely encounter with most camera lenses.

Basic Lens Anatomy

Barrel-The physical outer body of the lens which houses the internal components.

Elements-A term used for the individual internal pieces of glass which make up the optics of a lens.

Bayonet-The end of the lens that attaches to the camera body. Bayonets are designed in different “mounts” based on the camera they are intended to fit.

Zoom Ring-A circular ring which allows the photographer to control the zoom of zoom lenses.

Focus Ring-A ring present on virtually all lenses which allows the shooter to manually adjust focus.

Aperture Ring(manual lenses)-On fully manual lenses, the aperture ring controls the physical size of the aperture with no selection being made by the camera.

Basic Lens Terminology

Some of the most confusing aspects about lenses isn’t their physical operation but the terminology used to describe their characteristics. Here is a breakdown of some common terms and phrases you will encounter when talking about camera lenses.

Focal Length-At the risk of oversimplifying the concept, think of this is simply the magnification strength of the lens measured in millimeters. Shorter focal length lenses are deemed “wide-angle” while long focal length lenses are considered “telephoto”.

Prime-When we say that a lens is “prime” it means that the lens is a fixed focal length. Basically speaking, the lens doesn’t “zoom”.

Lens Speed-The speed of a lens is directly connected to aperture. The wider the maximum possible aperture a lens is capable of the “faster” the lens is considered to be. This means that the lens is capable of shooting in lower light situations at faster shutter speeds. Remember, the smaller the F/number of the wider the aperture. Check out “Aperture Simplified”  ,another one my articles here at LifePixel, for a nice and simple breakdown of aperture that will help make since of F/numbers….

What the heck is this symbol ⌀ anyway???-You will likely find this symbol located around the outside front of your lens along with lens speed and focal length information. Fear not, that little guy is just the indication of what circular filter(polarizer, neutral density, etc.) size your lens accepts. It will be accompanied by a measurement in millimeters. If you see a “⌀77” then you will need a 77mm filter. What’s more, if you lose a lens cap, that is also the size for the replacement.

And always remember….

Your lens and camera work as one piece of gear along with you and your creative spark.

Understanding how your lens functions and the basics of lens anatomy will not only make you a better photographer but also a more competent when it comes to acquiring the gear you need.  Arm yourself with all the information you can and build on the basics. Knowledge is power when it comes to lenses.