All features of a lens you should know

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The lenses of our cameras have a series of nomenclatures and numbers that at first we do not know what they mean. However, the most basic specifications that all the lenses have are very easy to learn.

Then, each brand has created its own nomenclatures and acronyms to specify certain characteristics that have their lenses . If you want to know how to recognize them in a simple way, do not miss this article.

Name and surname

All features of a lens you should know

To give you an idea, an lens has a name and a surname , regardless of the brand that is. The name is specified by its focal length, and the last name is the maximum aperture of the diaphragm .

The focal length is related to the angle of vision we have when taking the picture. It is measured in millimeters and the smaller the focal length a target has, the greater the angle of vision , that is, the more space it covers.

On the contrary, the greater the focal distance, the smaller the angle and let’s say we can see what is far away at a larger size, what is known as a lens with a lot of zoom or a lot closer.

Well, this would be the name of the objective. You have to know that we have lenses that have a single focal distance, for example, a 35mm, a 50mm , etc … With these lenses we always see the same unless we approach or move away from us. These lenses are known as fixed focal lenses.

All features of a lens you should know

The most common are the zoom lenses , that is, they have a range of focal lengths, so we can zoom more or less without moving from the site . These lenses have two numbers to specify the range of the focal length , for example, 16-35mm, 24-70mm, 70-200, 18-135mm.

With a 16-35mm we can photograph at a focal length of 16mm whose angle of view is greater than the 35mm, which extends a little more. 
As for the surname of a target, it is related to the maximum aperture of the diaphragm, that is, the number f. One of the most important things about an lens is how much we can open the diaphragm at most, since in this way more light will reach the sensor.

The maximum aperture is a parameter that comes with each lens. The more we can open it, the brighter it is, and normally, the more expensive . In the lenses , the following appears, 1: 4 to say that its maximum opening is f / 4. I could put 1: 5,6, where the maximum opening is f / 5.6 so we have to forget the 1 and the two points.

All features of a lens you should know
14mm fixed focal lens. If we look at the numbers on the right, we see that the maximum aperture is f / 2.8.

Therefore, when referring to an lens we have to say its focal distance (fixed or zoom) and its maximum aperture of diaphragm (number f). For example, I have a 16-35mm f / 4. This means that my lens can range from 16mm to 35mm focal length and as maximum aperture f / 4.

But surely you are looking at your goals and more numbers appear, for example, 1: 3.5-5.6. As before, we forgot the 1 and the two points and we were left with the rest of the numbers.

When more than one number appears after 1: it means that we have a zoom lens , that is, with a range of focal lengths and that the maximum aperture varies depending on the focal length that we use .

It seems more complicated than it really is. If I have an 18-55mm 1: 3.5-5.6 , what is telling us is that our lens has a focal range that goes from 18mm to 55mm . And when we are using a focal length of 18mm, the maximum aperture is f / 3.5. If we place the focal distance at 55m, the maximum aperture is f / 5.6 .

This means that the maximum aperture is smaller as we zoom in. This happens because of how each goal is constructed. There are lenses such as the 16-35mm f / 4 that keeps the maximum opening constant, and others that do not.

Obviously, it is better to have an lens  that does not close your diaphragm when you zoom, but they are also more expensive. The price of a lens is marked by the maximum aperture of the diaphragm.

The diameter

All features of a lens you should know

Another parameter that sometimes confuses is the diameter of the lens, for the simple fact that it is also measured in millimeters . One thing is the focal distance, which appears well visible on one side of the lens, or even on the front, and another thing the diameter that usually comes on the lid with an icon that has the shape of a circle with a line crossed out. Sometimes, the diameter also comes in the front, as you can see in the photo, but always carries the circle icon on one side.

The diameter is useful when buying a circular filter , since it has to have the same size.

So far we have seen the common parameters for all brands. From now on we will see some depending on the brand.

Image Stabilizer

Many targets have a stabilization system to compensate for our movement when shooting . This mechanism can be found under different names, such as IS (Image Stabilizer or Image Stabilizer) in Canon, VR (Vibration Reduction or Vibration Reduction) in Nikon. Fujifilm uses the abbreviation OIS (Optical Image Stabilization). Sony has the acronym OSS (Optical Steady Shot).

In the cover image we can see the tab of the image stabilizer. When shooting on tripod you have to deactivate it .

Type of approach

If the lens allows to focus automatically, something to which we are accustomed, a tab will appear that will put AF and MF on Canon cameras, and A and M on the rest.

AF or A means autofocus, and the lens will focus when we press the shutter button gently . If we put the tab in the M position it will not focus, and we will have to focus on it manually through the focus ring. Some lenses show you a scale of distances to know how many meters or centimeters we are focusing.

It may be useful to put it in Manual focus mode when shooting on a tripod.

Macro Lenses

The word Macro appears and this means that we can obtain photographs of very small objects at the natural size, achieving a great enlargement . This is achieved because the minimum focusing distance is very small.

Other parameters that may be useful



Canon cameras for the EOS system have the acronym EF (Electro Focus). A variant would be EF-S, for Canon cameras with APS-C sensor format. In this type of camera we can mount EF and EF-S lenses, however, in Full Frame cameras only EF type lenses.

USM stands for Ultra Sonic Motor, and is a type of focusing motor used by Canon Ultrasonic, very fast and silent . STM is another even quieter focusing system.

Canon’s L-series lenses are high-end and come with a red ring.


DX is the nomenclature that Nikon uses to specify the lenses for APS-C sensor format . If they are mounted on Full Frame cameras, they are automatically trimmed (clipping factor).

FX is for all cameras and tend to be more professional.

The lenses with the letter G have no way to control the diaphragm manually, only with the camera.


Di would be the equivalent of EF and FX, that is, they work for any type of sensor. Di-II only for APS-C.


DT specifies the lenses to be used with APS-C sensors.

G indicates that the lens is of professional range.

SSM refers to the type of focus motor, ultrasonic, fast and silent.


WR refers to those lenses that are sealed so that no water or dust gets into them.

The high range carries the acronym XF, the mid-range XC, maintaining the quality of the glass but reducing the quality of the rest of the materials.

If your goal has some acronyms that we have not seen, do not forget to check this other article .

Finally, there are a number of aspects to consider. Zoom lenses with a very wide focal range, for example, 18-200mm or more, also known as off-roaders are for those who do not want to carry multiple lenses or who do not want to continuously change targets. However, we must know that the quality of these lenses can not be equally good throughout the focal range . In fact, few professional lenses cover from an angular to a telephoto lens, precisely because of that. It is interesting to test each one’s lenses and see where they are weakening and what their strong point is.

In addition, the lenses have what is known as the sweet spot, which is where they offer the best quality . It is important to test, even at home, changing the diaphragm and compare the results on the computer by viewing the photo at 100%. Knowing your team thoroughly you can squeeze it well.

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