Aberration of a photographic lens is the last thing a novice photographer should think about. They absolutely do not affect the artistic value of your photos, and their impact on the technical quality of images is negligible. Nevertheless, if you do not know what to take your time, reading this article will help you understand the variety of optical aberrations and methods of dealing with them, which, of course, is invaluable for real photo-erudite.
Aberrations of the optical system (in our case, the photographic lens) is the imperfection of the image, Continue reading
Diffraction is an optical phenomenon that limits the sharpness of a photograph while reducing the relative aperture of the lens. Unlike other optical aberrations, diffraction is fundamentally unremovable, universal and equally common to all photographic lenses without exception, regardless of their quality and cost.
Diffraction can only be seen at 100% magnification. Notice how the image becomes less and less sharp with increasing aperture.
With the passage of light through the aperture, the bulk of the light waves continues to move rectilinearly. However, those waves whose path lies near the very edge of the diaphragm deviate from their original direction, trying to go around the obstacle that has arisen on their way. The smaller the size of the aperture Continue reading
A scatter spot (circle) is a distorted image of a point projected by a photographic lens onto the camera’s matrix or film. These distortions are caused, firstly, by structural factors, i.e. natural imperfection of optics and photosensitive material, and secondly, functional reasons, and above all – selective focus. An image of an infinitely small point can be a point only when it lies strictly in the plane of the matrix or film. If the image of the point is out of focus, the point turns into a blurry spot of rounded shape, the size of which increases with distance from the plane of the ideal focus (see also “Bokeh”).
Formation of a scattering circle. Continue reading
The dynamic range or the photographic latitude of the photographic material is the ratio between the maximum and minimum exposure values that can be correctly captured on the image. In relation to digital photography, the dynamic range is actually equivalent to the ratio of the maximum and minimum possible values of the useful electrical signal generated by the photosensor during exposure.
Dynamic range is measured in steps of exposure (EV). Each step corresponds to a doubling of the amount of light. So, for example, if a certain camera has a dynamic range of 8 EV, this means that the maximum possible value of the useful signal of its matrix refers to the minimum as 28: 1, which means that the camera is capable of capturing objects within one frame that differ in brightness not more than 256 times. More precisely, it can Continue reading
For full control over the process of obtaining a digital image, it is necessary, at least in general terms, to imagine the device and the principle of operation of a digital camera.
The only fundamental difference between a digital camera and a film camera is the nature of the photosensitive material used in them. If in a film camera this is a film, then in a digital one – a photosensitive matrix. And just as the traditional photographic process is inseparable from the properties of the film, so the digital photoprocess largely depends on how the matrix converts the light focused on it by the lens into a digital code.
The principle of the photomatrix
The photosensitive matrix or photosensor is an integrated microcircuit (in other words, a silicon wafer), Continue reading