What the numbers on lenses mean.

Hello! If you want to dip your feet into the world of photography, buying your first SLR can be a daunting task. Through a series of blogs I hope to help you make informed decisions and possibly learn a little extra about photography and your camera long the way.

Today we are going to tackle LENSES and what all those little numbers mean.

Now depending on what camera you have you may have to pay attention to different things. I have worked with the two most popular brands, Canon and Nikon primarily, which is what I will be talking about here. 

Pictured above on the left is a Canon Lens. If you see a red ring like the one above it is probably an expensive lens. Nikon has the same mark except their ring is gold as seen above. In 2003, Canon introduced the EF-S lens mount, a derivative of the EF mount that is strictly for digital EOS cameras released after 2003. EF lenses can be mounted on EF-S bodies but EF-S lenses cannot be mounted on EF bodies. Simply put, if your lens is newer, it wont go on an old body.  Nikon on the other hand has not changed their mounting system which is one reason I shoot Nikon. My lenses will still work on an old film SLR.

On both cameras, the front rubber grip is the focal ring. On a Nikon you spin clockwise to zoom in, on a canon you spin counterclockwise.  Just beneath the red ring, you see "Canon Lens EF 14mm 1:2.8 L II USM." On the nikon the lens description is located in the center of the lens. It says "AF-S NIKKOR 24-70mm 1:2.8G ED So lets break all that down.


The canon shown here is a wide angle lens. That is what the "14mm" indicates. Anything below 50mm is considered a "wide" lens. This allows you to see more of what is in front of the camera, but it also distorts the image more and more the lower you get. This image below is a solid visualization of it. Wide lenses are usually used for landscapes. It is also the type used in smartphones.

Now the canon only shows one number. This means it is a fixed lens, it does not zoom. The Nikon I showed you said 24-70mm which means you can zoom from you guessed it, 24mm to 70mm. At this end, anything above 50mm is considered a telephoto lens. This will make things that are very far away look close up. This is really nice if your shooting a kids soccer game from the stands.  However a telephoto can distort a photo via compression. In the gif below, watch how the tree in the background seems closer and closer to the subject as the focal distance increases. What the gif doesn't show you, is as the photographer zooms in, he is also backing up away from the subject.


The speed of a lens. This refers to the aperture or "F-stop." The ratio number 1:2.8 indicated on both lenses tells you the maximum aperture is F2.8 The numbers are counter intuitive, the smaller the number the bigger the opening of the pinhole (Remember "how your camera works".) The bigger the opening the more light is allowed in. The faster your lens, the less light you need. This becomes very helpful when you are shooting indoors or at dusk. 

Usually on less expensive lenses you will see a maximum aperture that varies. For example, on the Fujifilm lens below: You see 1:2.8-4 Now this lens is a 18-55mm so what it all adds up to is at 18mm, your max aperture is F2.8, but as you zoom in, your max aperture will get slower and slower until the widest your lens will open is F4 at 55mm. One of the reasons the pros pay so much for lenses is because they want 2.8 or faster no matter what focal length.


So that is it for the numbers, only thing we left out is a seemingly random assortment of letters. The letters on the lenses always refer to either the model, or a certain bell/whistle the lens may have. All of the Nikon abbreviations can be found here. and for Canon, click here.

If I did not answer all of your lens based questions, comment below!  I also want to hear what you have to say, do you have a favorite lens?