The purchase of an SLR camera only makes sense for three main reasons. One is the size of the sensor. Another is the delay that compact cameras usually have when shooting that prevent capture the moments that occur in an instant, such as pictures of children in movement, animals, waves, etc. And the third reason is the exchange of objectives.

In another case there are compact cameras in the market that offer very good image quality and thus we will save money and carry less volume and weight. When choosing objectives to buy, it is very important to think what kind of photos are we going to make and then choose the ones that best suit what we want. And to help you make that decision, in this guide you will find very useful tips

Colección de objetivos de Canon

Canon Lens colection

The lens can be classified according to their different characteristics: whether they have image stabilizer or not, their brightness, their focal length, etc., but in this article I will discuss about the focal distances in different lens. In a simple way we can define that the focal distance of a lens is the distance that exists, expressed in millimeters, between the sensor (focal plane) and the optical center of the lens.

A first advice is that we get a quality lens from a brand we trust, with a wide range in its catalog that covers our current and future needs. Since every brand uses a different type of mount to assemble the lens to the camera and the lens from one brand do not work in another, once you buy a camera with a pair of lenses it is no longer possible to swap brands (unless we sell the camera and lenses and start buying again).

When we use lenses in a non-full-frame camera, the focal length varies depending on the crop factor of the camera sensor. In Cameras with APS sensor we must multiply the lens focal length by 1.6 for Canon lenses, by 1.5 for Nikon lenses, and by 2 for cameras with 4/3 system.

The fixed and non-stabilized lenses are those that give us the highest image quality due to the lower number of lenses that the light has to pass through and therefore less diffraction is produced. As they are non-stabilized, with low shutter speeds, our photographs may be trepidated.

On the other side, the stabilized lens avoid trepidation at low shutter speeds, but when using this group of lenses to avoid trepidation, they subtract some quality from the images.


Types of most common lens according to their focal length:


Canon Lens 50mm

Normal or Standard Lens: this is one whose image resembles what the human eye sees and our brain usually processes. A 50mm focal length is considered the standard objective.

They give a very high image quality to a single lens.


Objetivo Canon 17-40mm fotografos alicante

Canon Lens 17-40mm


Angular lens: Ultra wide-angle from 16 to 24mm, wide-angle from 28 to 35mm, and Fish eye from 6 to 16mm.

These objectives allow us to capture a wide visual field, they are very appropriate for small places, interiors of houses or cars. Due to its short focal distance it prevents blurring of the background that highlights the main subject.

They are usually quite bright because of their short focal length and have very large openings of the order of f2.8 or f4.

The depth of field is directly linked to the focal distance, and at a shorter focal distance greater depth of field. With these objectives we can focus on the closest subjects and the background, very appropriate for landscape photography.

These lens distort the images, the lines of a vertical building photographed closely and from below converge towards the center, giving the sensation that the building lies backwards. This feature is used in creative photography to achieve special effects, but on the contrary it is not appropriate for portrait photography because it exaggerates the features and prevents blurring the background to highlight the subject.

Fisheye lens are those that produce more exaggerated effects, it has a viewing angle of 180º or more. They give us circular images.

Teleobjetivo Canon 70-200mm

Canon telephoto lens 70-200mm

Telephoto lens: they are those whose focal length is between 70 and 1200 mm.

They have the characteristic of bringing distant objects closer. They are used to photograph animals in their natural habitat and in landscape photography to capture distant details.

The greater the focal distance, flatter the image and smaller the depth of field. Little depth of field allows us to blur the background and thus highlight the subject motive of our photography.

When using these lens we must have in mind that we can get trepidated images. A very useful rule is to shoot with a shutter speed equal to or greater than the focal length, for example, if the focal length we are photographing is 400mm, the speed should be at least 1/400.

Due we had to increase the shutter speed and also these objectives are not usually very bright, maybe we have to increase the ISO value or better make use of a tripod. The short telephoto lenses between 70 and 135mm are used for portrait since they allow us to blur the background and can be shot by hand without a tripod.


Objetivo Canon Macro 100mm

Canon Macro Lens 100mm

Macro Lens: they are those that have been designed to approach the subjects. The Macro lens is the one that obtains magnifications of 1: 1 (natural size).

Generally, they allow us to obtain close up images of flowers, insects, etc., it is also used to make creative photographs.

Although some telephoto lenses have the option of making macros, as well as most compact ones, if we want to obtain quality macro photographs, the best thing is a macro lens and a SLR, since they will allow us larger extensions and have fewer aberrations.

The focal lengths of the most common Macro Lenses are between 50 and 100mm. There are also 150 and 200mm.

With a 50mm Macro we have to be on a distance of 20cm from the subject. With one of 100mm the distance would be 30cm. And with one of 200mm the distance will be 45cm. In order to photograph insects, the macros of greater focal distance are used to allow us to be at a certain distance and not disturb them.


 Objetivo Tilt & Shift

Tilt & Shift Lens

Another type of lens is the Tilt & Shift: It is widely used in architectural photography. It has two complementary functionalities: Tilt makes it possible to tilt the objective, and Shift allows to move the objective of its axis.

After all that has been said, there may still be doubts about which objectives to buy. A basic equipment would be, for a full-frame camera, a standard zoom lens of 28-80mm, or a 24-105mm, and a telephoto lens of 70-200mm, or 70-300mm. Later we can add a 100mm Macro, a wide angle of 17mm – 40mm and a fixed lens of 50mm.