A zoom lens is the opposite of a prime lens. While the latter has a fixed focal length, the former has a variable one. Usually, it is represented in millimeters and you can find the shortest and the longest focal lengths range on the barrel. For example, 18-55mm, or 70-200mm.

A telephoto lens allows shooting from far away as it can significantly magnify the subject. Usually, these are the lenses that have a long focal length of 85 mm and more. They can be both primes and zooms.

That is why zooms are very common lenses and are great in many cases — street and press photography, wildlife, and so on.

Depending on your shooting environment and goals, both of them can be a great selection. If flexibility is what you need, then go with a zoom. Landscapes or architecture will still look great in your family photo slideshows. If you are taking pictures in a more specific environment, like sports events or wildlife, a telephoto lens could really bring your photos to the next level.

Aperture in biology

Another factor in depth of field is your choice of lens. Different lenses have different depth of field characteristics, which is caused by the magnification of the lens. The greater the magnification (as with telephoto lenses), the shallower the depth of field, and vice versa.

A lens is an important element of any camera. A kit lens that usually goes with a DSLR camera can be a good starter, but at some point, we start looking for something else to take our photos to the next level.

There are three different factors that influence depth of field — aperture, distance from your subject and magnification. First, let’s look at how to change your depth of field using different aperture settings.

Aperture of lens

The larger the aperture, the more light is recorded and the shallower the depth of field. With smaller apertures, less light is recorded and the depth of field is greater. Aperture is recorded in f-stops and is shown by the symbol ‘f'.

Aperture in camera

The variable focal range can be helpful for a quick reframing of a scene without changing lenses or physically moving closer or further away. You just need to rotate the zoom ring to get a new composition in the viewfinder. Therefore, you don’t need to buy and carry many lenses with you, saving both your money and space.

Is it important what type of lens is used for taking photos? With a new one, will the photos become better? Is there an all-in-one lens?

Aperture in microscope

Additionally, they can be divided into short telephoto (85mm - 135mm), medium telephoto (longer than 135mm), and super telephoto (longer than 300mm+). The further your subject is, the longer focal length you need.

An aperture of f22 was used for the image above. You can see how the depth of field runs much further, keeping both model and the background in sharp focus. (See how Karl captured this image here).

Magnification can refer to the sensor size, focal length and distance from the subject. For example, a larger sensor size, longer focal length or closer focusing distance will result in shallower depth of field. At the same aperture, full-frame cameras will have a shallower depth of field compared to crop-sensor cameras. Again, at the same aperture, medium-format cameras will have an even shallower depth of field than full frame cameras.

Aperture in physics

Aperture pronunciation

Telephoto lenses are good for shooting street photos, portraits, spy photos, wildlife, sports, action, night sky, and stars. They let more light in and can produce a very beautiful contrast between the subject and the blurred background. Also, these lenses portrait the objects very naturally and without distortions.

This means that if you’re shooting at f4 using a 24mm focal length 10m from your subject, you will have much greater depth of field than if you were shooting f4 using a 200mm focal length at a distance of 10m.

Aperture of mirror

Aperture photography

Also, you can meet the so-called ratio, to describe zoom lenses, for example, 3:1 or 3x. It is calculated by dividing the longest focal length by the shortest and meaning how much you will be able to zoom in (zoom out).

If you’re shooting in Manual mode, you have the greatest level of creative control, but you have to balance your aperture and shutter speed to get the best exposure. In any of these modes, you can simply adjust your aperture using either the front or back control wheel of your camera.

DoF is also dependent on the distance from your subject. The closer you are to the subject, the shallower your depth of field will be. Shooting from further away will give a much greater depth of field. This is due to magnification.

If you’re shooting in Auto mode, your camera will decide the ‘best’ aperture for you. If you’re shooting in Aperture Priority mode, you can simply set the aperture by using your camera’s control dial and your camera will automatically determine the shutter speed.

If zoom lenses are so flexible, why haven’t they replaced the others? The main reason here is image quality — common zooms, especially those having a ratio larger than 3x, cannot produce photos as sharp as primes do. Also, they usually cannot capture as much light as the fixes. Moreover, even though these lenses can zoom in a lot, you might still want to use a dedicated macro lens to make exceptional close-up photography.

As we discussed in Chapter 1, aperture refers to the opening through which light passes before hitting your camera’s sensor. By controlling the size of that opening, we can control how much light is recorded in an image as well as the depth of field.

So telephoto and zoom lenses are not the same. The main distinguishing point between them is their focal length. A lens that has the shortest value of up to 85 mm will be just a zoom, everything that is above it can be called a telephoto lens.