Camera Lens

The quality of the lens depends largely image quality,clarity, sharpness, lack of distortion. Amateur photographers can recommend to medium telephoto zoom lens with the camera, aperture of the order of 2.8 and autofocus.

Important elements of the lens are the lens and iris. The lenses are responsible for the nature of light, and the aperture allows you to control the quantity. Choosing the right lens, it is important to note that these optical devices differ in the length of the focal length and, of course, the viewing angle, change it  and the amount of light falling on the matrix the value of the relative aperture . The system automatically Focusing  one more parameter of the lens, which can influence your choice. Amateur photographers can recommend to medium telephoto zoom lens with the camera, aperture of the order of 2.8 and auto-focus.


Autofocus

This automatic guidance system on the sharpnessis used in many digital SLR cameras. One of its most important parameters - speed, which is defined, basically, the mechanics of the lens. Currently, there are two types of drives, shifting the lens when focusing  "screwdriver" (its elements are placed in the camera body), and ultrasound. High speed and quiet ultrasonic motor is built into the lens, which allows sharing and automatic and manual focus. That's why this technology is most popular in the serious amateur and professional equipment.

The main condition of AF a sufficient brightness of the subject and the presence on it of contrasting elements. When choosing a camera for shooting indoors or in the dark is worth paying attention to the "reflex" system with auto-focus light. For this purpose, the camera (or in the case of external flash units) placed a special lamp that flashes when you press the button "shutter" in half, that is, at the start of the autofocus system. In some cells used for this purpose built in flash in a special "stroboscopic" mode. For the most reliable decision autofocus illumination system draws on the object contrast "grid".

And when choosing a camera for shooting sports or animals, you should pay attention to the modern DSLR with intelligent algorithms of AF systems.


Focal length and aperture

The most common lens with a viewing angle of about appropriate viewing angle of human eyes are medium telephoto, 50mm lens. The specified focal length allows you to effectively remove the objects that are in one meter away from the photographer, and 10 meters, and at a considerable distance. To take a three-dimensional objects at close range are used short-focus lenses with the long focal length from 10 to 35 mm. And for photographing distant objects are long focus lenses(telephoto), with a focal length of 300 mm. But now there is no need to choose any of the proposed types of lenses: the last time manufacturers began to produce lenses with variable focal length - the system of "zoom". However, it should be noted that not all have a good zoom lens aperture at all focal lengths, "zoom", and in selecting the optimal objective important to consider this option.

Aperture characterizes the amount of light transmitted by the lens matrix. Determined by the aperture value is responsible for the amount of light overlooked lens. The lower the aperture number, the larger the aperture of the lens. For example, the lens aperture value 2.8 misses more light than a 3.5 aperture. In deciding on the choice of the lens, it's worth to remember that in the same lighting conditions, a lens with more aperture allows shooting at faster shutter speeds.


Image Stabilizer

This device, designed to eliminate the blur images due to shaky hands when taking pictures at sufficiently high exposures, or when a large zoomed. When choosing a camera, be aware that the "SLR" stabilization system used two types - with a moving element inside the lens or with a mobile camera inside the matrix (technology anti-shake). The latter allows you to work with any lens, and therefore more convenient.


Optical stabilization is based on the fact that the movable stabilizing element is built into the lens. This system is very effective, especially at long focal lengths, but it makes the lens more expensive and slightly reduces its luminosity.

When anti-shake technology moving element is the matrix itself. The main advantage of this system is the independence of stabilization on the lens.