Comparison Canon 18-135mm f/3.5-5.6 EF-S IS vs Canon 24-105mm f/4.0L EF IS USM

The type of mount used to connect the lens to the camera. The name comes from the English "bayonet", meaning "bayonet" and a bayonet-type connection. Bayonet mounts are used in the vast majority of modern digital cameras due to their reliability and ease of use.

Full compatibility of the lens with the camera is guaranteed only if the types of their mounts match. Some mounts are compatible with each other via adapters, but such a connection can limit the capabilities of the lens (for example, it will make it impossible to use autofocus) and is generally not considered optimal. It is worth considering that within the same system (see above) different mounts are often used, which are also incompatible with each other.

So, the manufacturer Canon has mounts EF-M, EF-S, EF, RF, RF-S. Leica has Leica M, Leica SL, Leica TL. Nikon has Nikon 1, Nikon F, Nikon Z in its arsenal. Pentax optics are equipped with Pentax 645, Pentax K, Pentax Q. Samsung uses NX-M and NX mounts. Sony models include Sony A and Sony E. In addition, there are other types of mounts on the market - both branded ( Fujifilm G, Fujifilm X, Hasselblad H, Sigma SA) and universal ( Four Thirds (4/3), Micro 4/3).

Note that there are lenses that are declared compatible with several mounts at once. This “omnivorousness” can be realized in different ways. For example, some models have a non-standard mount on the lens body, and compatibility with various mounts is ensured through the use of adapters; These adapters can be included in the delivery set or purchased separately. Another option is that the lens is available in several separate modifications, each for its own mount. These details should be clarified before purchasing.

Lens aperture is a characteristic that determines how much the lens attenuates the light flux passing through it. It depends on two main characteristics — the diameter of the active aperture of the lens and the focal length — and in the classical form is written as the ratio of the first to the second, while the diameter of the active aperture is taken as a unit: for example, 1 / 2.8. Often, when recording the characteristics of a lens, the unit is generally omitted, such a record looks, for example, like this: f / 1.8 or f/2.0. At the same time, the larger the number in the denominator, the smaller the aperture value: f / 4.0 lenses will produce a darker image than models with f / 1.4 aperture.

Zoom lenses usually have different aperture values for different focal lengths. In this case, the characteristics indicate two aperture values, for the minimum and maximum focal lengths, respectively, for example: f / 4.5-5.6

The larger the aperture of the lens, the shorter shutter speeds it allows you to use when shooting. This is especially important when shooting fast-moving subjects, shooting in low light, etc. And if necessary, the light stream transmitted by the lens can be weakened using a diaphragm (see below).

Another point that directly depends on this indicator is the depth o...f field (the depth of space that is in focus when shooting). The higher the aperture, the smaller the depth of field, and vice versa. Therefore, shooting with artistic background blur (bokeh) requires high-aperture optics, and for a large depth of field, you have to cover the aperture.

This parameter determines the size of the area of the scene being shot that falls into the frame. The wider the viewing angles, the larger the area the lens can capture in one shot. They are directly related to the focal length of the lens (see "Focal length"), and also depend on the size of the specific matrix with which the optics are used: for the same lens, the smaller the matrix, the smaller the viewing angles, and vice versa. On our website, in the characteristics of optics, viewing angles are usually indicated when used with the matrix for which the lens was originally designed (for more details, see "Matrix Size").

The degree of magnification of the object being shot when using a lens for macro shooting (that is, shooting small objects at the maximum possible approximation, when the distance to the subject is measured in millimetres). The degree of magnification in this case means the ratio of the size of the image of the object obtained on the matrix of the camera to the actual size of the object being shot. For example, with an object size of 15 mm and a magnification factor of 0.3, the image of this object on the matrix will have a size of 15x0.3=4.5 mm. With the same matrix size, the larger the magnification factor, the larger the image size of the object on the matrix, the more pixels fall on this object, respectively, the clearer the resulting image, the more details it can convey and the better the lens is suitable for macro photography. It is believed that in order to obtain macro shots of relatively acceptable quality, the magnification factor should be at least 0.25 – 0.3.

A type of drive that ensures the movement of lens structural elements during automatic focus. Currently, the following types can be used:

— Ultrasonic motor. The most advanced type of drive to date. Ultrasonic motors are much faster than conventional motors, provide higher accuracy, consume less power and are virtually silent. However, their cost is quite high.

— Stepper motor. Drive control focal length and zoom (zoom). This type of motor is used for the most part only in full-size digital cameras. Among the advantages of a stepper motor, one can note: high reliability and accuracy of operation; in addition, it does not require power supply to maintain focus and zoom. Of course, stepper motors are not without drawbacks. Among the minuses can be identified: slow speed and increased noise. Additionally, a stepper motor is characterized by large dimensions and a rather large weight, which physically does not allow this type of drive to be integrated into the optics of mobile phones and ultra-compact cameras.

— Motor. In this case, an electric motor of a traditional design is meant. Such drives are simple and, as a result, inexpensive. Their disadvantages are the relatively low speed of operation, as well as the noise produced during this; the latter can sometimes be critical — for example, when shooting wildlife. Recently, designers have been us...ing various tricks to neutralize these shortcomings, but in general, the characteristics of conventional motors still remain relatively modest.

— Is absent. The complete absence of an autofocus motor in the lens. Focus such optics can be carried out either by the “screwdriver” system, or strictly manually (for more details on both options, see below).

The number of elements (in fact, the number of lenses) included in the design of the lens, as well as the number of groups in which these elements are combined. Usually, the more elements provided in the design, the better the lens handles with distortions (aberrations) when light passes through it. On the other hand, numerous lenses increases the dimensions and weight of the optics, reduces light transmission (for more details, see "Aperture") and also puts forward increased requirements for the quality of processing, which affects the cost of the lens.

The number of blades provided in the design of the diaphragm (for details, see "Minimum aperture"). In fact, this parameter is important when shooting scenes with pronounced bokeh (blurred background) and a small depth of field: the more petals the aperture has, the smoother the glare from out-of-focus objects will turn out, while with a small number of petals they can look like polygons. The number of aperture blades has almost no effect on other shooting parameters. Modern lenses have an average of 7-9 petals; the smoothing provided by them in most cases is considered quite sufficient.

Lenses with protection against ingress of dust and moisture. "Protected" optics are useful primarily for those who have to shoot a lot outdoors: they are much more resistant to bad weather than ordinary ones, many of these lenses work quietly in the rain, sea spray, etc. However, the specific degree of protection for different models can significantly differ, this point should be specified separately in the official documentation of the manufacturer. Also note that if you intend to constantly shoot in difficult external conditions, not only the lens, but also the camera itself must have dust and water protection.

Thread diameter for installation on the filter lens. Light filters are devices for changing the parameters of the light flux entering the lens. They can be used for highlighting individual colours, coloring the entire image in one colour, darkening the image, correcting colour temperature and light balance, shooting in the infrared range, etc. Also, a light filter can play the role of protection against pollution. For successful installation on the lens, the diameter of the filter must match the diameter of the filter specified for this model of optics.