Reading the barrel of your lens

Today I wanted to move away from camera settings and talk about the capabilities of your lens. Did you know the barrel of your lens gives you so much information? I’ll touch upon the basics of what most lenses will tell you. There is a lot of variation between brands, even within the same brand, of what is written on there. I shoot with Nikons so those are the lenses you will see in this post. Different brands will use some different terminology, but you’ll see even the two Nikon lenses I show here have some variation.


Understand your lens, read the barrel of your lens


Looking at these two lenses, would  you be able to decide which one is right for you? There is a whole lot written on there but it all looks a little bit like gibberish right? A lot of this is probably terminology you are already familiar with, it’s just hard to tell what it’s saying when it’s all lumped together like this. At least that’s what I realized was happening to me 😉 Until a few years ago, I didn’t even pay attention to what was written on my lens. All I really cared about was the focal length and whether or not it was a zoom. Ha! The more you start to learn about photography however, the more you will realize there is some important info here! So, let’s take a look at these side by side and compare.


lens basics, how to read your lens

What your lens is telling you –

  1. In the examples above, #1 is probably the most obvious thing on lenses. This is the focal length of your lens. You will see the shorter lens on the right is a 50mm lens. This is what is called a prime lens. It’s prime because it has one focal distance, you cannot zoom in or out. If you want to get closer shots or take in more of the scene, you’d do this by moving closer of further away from your subject. It’s what you’ll often hear called “zooming with your feet!” The larger lens on the left is a zoom. How do you read this? 18-200mm means the widest angle (smaller number) it can go is to 18mm. This is a wide angle which sure does allow you to take in lots of scenery, but it does start to distort around the edges. Keep that in mind when using your zooms or wide angle primes! 200mm is the closest it can zoom in. That is a pretty good range. You’ll see markings on the barrel 18, 24, 35 etc. You can use the zoom ring just above those numbers to manually set your focal length. Many lens and camera combinations will also allow you to control this from the camera and you can get lengths in between too, such as 28mm.
  2. #2 in this picture is telling you the aperture on the lens. Remember aperture is a fractional number, that is why you see a number 1 in front of what looks like a standard aperture number. If you need to catch up on aperture, you can read about it in this post. The prime lens again is fairly easy to read. 1.8, great. That is my maximum, or widest, aperture. The zoom is a little trickier to understand. This is something that blew me away once I learned it. The first aperture number is tied to the shortest focal length. The second aperture number ties to the longest focal length. What exactly does this mean? It means that at 18mm, the widest aperture you can set is 3.5. At 200mm, the widest aperture is going to be 5.6. All the other focal lengths in between will fall somewhere in between that range. I haven’t had this lens on a camera lately so I don’t have an exact example. For instance, you can image that at 70mm, your widest aperture may be 4.5.
  3. This little window shows you the focusing distance from your subject. This is fun to play around with. You can setup a test shot and focus on a subject, check the window and see where it falls. Focus on something a little further away, then closer up. Pay attention to how it keeps moving and where your focus is falling. I don’t use this too much, it’s on almost all the lenses I have. I usually can get away with using my auto-focus so this is not terribly important to me. Occasionally I’ll switch to manual focus and sometimes it can be difficult to tell with certainty what you are focusing on. Keep in mind, you are looking through a tiny viewfinder on the back of the camera so it might be difficult to see the exact spot you’ve focused on. Checking your focus distance can help you at least know whether or not you are in range of where you want to focus on your subject. It shows you the distance in feet and in meters so pay attention when you are checking! What is that infinity symbol on the zoom? Both lenses have it, I just wanted you to see the scope of what the measurements look like on the prime lens. The infinity symbol is just that, it sets the focus distance to infinity, far, far way. To put it simply, you’ll see this used when you are trying to focus on something so far it’s difficult to catch focus on. People shooting the night sky, trying to keep stars in focus is a good example of when focus to infinity would be set.

A few other things on these lenses

In case any of you are Nikon users, I wanted to point out what some of the other markings on the barrel mean.

VR – This indicates the lens is equipped with vibration reduction.

ED – This is a type of glass used by Nikon to help produce sharper images.

AF-S – You’ll see this one both lenses. It indicates that auto-focusing is silent.

DX – This is only on the zoom. DX is the format Nikon uses for Crop-sensor camera bodies. A crop sensor camera is generally more of a hobby or semi-pro body. Full frame (FX) would be considered a professional camera body. You do not see that marking on the prime lens in this case because this lens happens to work with both.

G – This indicates that there is no aperture adjustment ring on the lens.

II – You see this on the zoom, it simply indicates it’s the second generation of this particular lens.

These markings are not terribly important. Once you get more in depth you may care about the type of glass used, or vibration reduction, etc. I’d say the main thing here is to pay attention to the DX or FX format. You’ll need to know if you have a full-frame or crop sensor camera in order to determine the right lens for you. Again these are Nikon specific so if you have another brand, you won’t see these. They will have their own way of marking lenses.