Aperture - the most important characteristic of the lens, which largely determines the quality of the image.
Despite the fact that it is rather complicated optical property, the gist of it is pretty simple to understand.
What is the maximum aperture
Photo or video - is fixed onphotosensitive surface (in the case of digital technology - on the matrix), the flux of light passing through the lens. Optics in photography plays a crucial role and its quality largely determines the quality of the future picture.
Any object consists of several lenses,combined into groups. Each of them has its own function. The lenses refract light, focusing it on the sensor, protected from distortion, reflections and other negative optical effects. Passing through these "barriers" naturally luminous flux weakening. As a result, the light that strikes the CCD becomes less bright, dim.
There are many ways to helpavoid "loss of light", of which the most effective - use of lenses that, passing through which light will lose a minimum of intensity. So, the objective ability to pass the greatest amount of light without losing intensity and aperture is called.
How to determine the luminosity
Aperture - a complex concept and its significancemanufacturers expressed using the number of coefficients. So, the most simple, inexpensive zoom lenses of modern cameras have an aperture ratio of 3.5 to 5.6 units. The lower the ratio, the higher the lens aperture. The biggest aperture of the lens has a Carl Zeiss Planar 50mm f / 0.7, designed for shooting in space. Lenses with a high aperture to shoot on the ground have a range of 0.7 to 2.8 units.
Lens Carl Zeiss Planar 50mm f / 0.7 was used for the reverse side of the moon shots.
As the aperture affects the quality of shooting
Aperture determines not only the intensity of theluminous flux, which allows shooting with shutter speeds at very low light. It is also associated with a relative aperture diameter. The higher the aperture ratio, the larger the aperture ratio, and hence the smaller the depth of field. This is particularly important in portraits, as with such a lens, you can select objects in the foreground and blur the background.
The largest aperture lenses have a fixed focal length.
That is why the aperture - the most important characteristic for a portrait lens and any professional portrait photographer has an aperture optics in its arsenal.