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The term means that the point of focus appropriate terminology gathering place through an optical light or lens. In photography, a focused image is obtained by placing a collection of light at the exact point being in a movie or on the sensor (called focal plane). When the dot is formed in front of or behind the focal plane, the resulting image becomes unfocused or out of focus.
The lens of the camera, like the human eye, should ideally be able to focus on objects that are close or far away with just as good. But there is the nearest boundary where the lens can lock the focus, while the farthest limits commonly referred to infinity (infinity). In camera lenses are optical elements that can move back and forth to adjust the distance to objects in front of him so that the fall of the beam direction can still be collected at the focal plane. Exceptions to the camera with fixed focus lens manifold, where no lens element that can move. Camera with fixed focus and use a small aperture wide angle lens that is simple to save on costs such as camera phones.
Once upon a time, the lens on the camera requires setting the focus manually. To focus, we have to rotate the focus ring on the lens and see the effect in the viewfinder to get the sharpest image according to our judgment. Fortunately, in the end found auto focus technology that allows us to take pictures. With auto focus, the camera automatically moves the lens elements to obtain the best results, in a fairly short time.
In modern cameras are digital, there are two differences in the working principle of auto focus depending on the type of camera. In a DSLR camera, auto focus is still the same principle as film SLR cameras using the principle of phase detection (phase detect) using a separate module. This system is more complicated, expensive but very accurate and fast. In addition to DSLR cameras such as compact cameras to the new format cameras such as the micro four thirds, the principle use contrast detection auto focus (contrast detect) is more cost-effective.
The principle of contrast detection is actually present in the digital age whose characteristics capable of displaying a preview of the image to be captured via the LCD screen. What appears on the LCD is what is received by the sensor, so-called live-view. With live-view, a lot of information that can be processed before the photo was taken, call for example the color information (for setting white balance), dark light information (for setting exposure) and contrast information (for setting auto focus). Modern DSLR cameras that already have a live-view feature brings two principles AF, good concept phase detect and contrast detect. Under normal conditions of speed and accuracy, DSLR cameras would use phase detect module as its default mode. However, when using live view with a stationary object (such as macro photo), we can use contrast detect mode by utilizing the magnification on the LCD screen, so we can be sure that the focus is taken just right.
The process begins when the auto focus shutter button is pressed halfway. When the camera immediately moves the focus element inside the lens back and forth to get the best contrast and give a confirmation in the form of sound 'beep' as a sign've managed to get the focus. This whole process takes between less than one second to several seconds. At DSLR, auto focus speed is much faster than other cameras for wearing special module principled phase detect AF. But whatever the method, there are some things that determines the speed cameras in finding focus, including:
In addition to pressing the shutter button halfway, the camera is a serious class as prosumer cameras and digital SLR cameras, there is the AE-L / AF-L that can be used to lock the focus. AE-L stands for Auto Exposure - Lock, while AF-L stands for Auto Focus - Lock. in settings further, this button can be customized into several functions, such as exposure and focus lock as well, or just lock the exposure, focus lock it, and lock the focus during this button is pressed (AF lock-hold). Choose which one best suits your wishes.
Initially known as auto focus, the camera simply choose the midpoint of the object image as a reference focus. This turned out to be difficult when the objects are not actually in the middle area of the photo. So it then made the zone of focus or focal point spread in some areas of the photo. Generally, there are now at least three zones, namely focusing middle zone (main), left the zone and right zone. The more powerful the more the camera focal zones are available so that they can be more flexible and avoid mistakes locking focus. Special modules on DLSR camera AF, the AF point can be any cross-type sensors aka cross-type sensors. Such sensors are sensitive to differences in contrast both vertically and horizontally. The central AF point is certainly manifold cross type, while the other point is not necessarily. The more diversified cross-type AF points, and the more accurate the more expensive DSLR camera is in focus.
In addition to the focus zone, there are now more options on the camera auto focus mode, the servo AF mode option. Options are stationary or continuous, and adapted to the conditions of the object to be photographed. Stationary mode is chosen for stationary objects, and these tend to be the default mode on most cameras. Continuous mode will detect the movement of objects and try to continue to follow wherever the object moves. Currently DSLR camera was able to lock focus on a moving object left or right forward backward (3D tracking AF).
The lens of the camera, like the human eye, should ideally be able to focus on objects that are close or far away with just as good. But there is the nearest boundary where the lens can lock the focus, while the farthest limits commonly referred to infinity (infinity). In camera lenses are optical elements that can move back and forth to adjust the distance to objects in front of him so that the fall of the beam direction can still be collected at the focal plane. Exceptions to the camera with fixed focus lens manifold, where no lens element that can move. Camera with fixed focus and use a small aperture wide angle lens that is simple to save on costs such as camera phones.
Once upon a time, the lens on the camera requires setting the focus manually. To focus, we have to rotate the focus ring on the lens and see the effect in the viewfinder to get the sharpest image according to our judgment. Fortunately, in the end found auto focus technology that allows us to take pictures. With auto focus, the camera automatically moves the lens elements to obtain the best results, in a fairly short time.
In modern cameras are digital, there are two differences in the working principle of auto focus depending on the type of camera. In a DSLR camera, auto focus is still the same principle as film SLR cameras using the principle of phase detection (phase detect) using a separate module. This system is more complicated, expensive but very accurate and fast. In addition to DSLR cameras such as compact cameras to the new format cameras such as the micro four thirds, the principle use contrast detection auto focus (contrast detect) is more cost-effective.
The principle of contrast detection is actually present in the digital age whose characteristics capable of displaying a preview of the image to be captured via the LCD screen. What appears on the LCD is what is received by the sensor, so-called live-view. With live-view, a lot of information that can be processed before the photo was taken, call for example the color information (for setting white balance), dark light information (for setting exposure) and contrast information (for setting auto focus). Modern DSLR cameras that already have a live-view feature brings two principles AF, good concept phase detect and contrast detect. Under normal conditions of speed and accuracy, DSLR cameras would use phase detect module as its default mode. However, when using live view with a stationary object (such as macro photo), we can use contrast detect mode by utilizing the magnification on the LCD screen, so we can be sure that the focus is taken just right.
The process begins when the auto focus shutter button is pressed halfway. When the camera immediately moves the focus element inside the lens back and forth to get the best contrast and give a confirmation in the form of sound 'beep' as a sign've managed to get the focus. This whole process takes between less than one second to several seconds. At DSLR, auto focus speed is much faster than other cameras for wearing special module principled phase detect AF. But whatever the method, there are some things that determines the speed cameras in finding focus, including:
- - There is a good contrast to the object to be photographed. The lower the contrast of the object to be photographed, the camera is more difficult to get the right focus.
- - The lighting conditions around the object to be quite good and not dark. Dark current is usually helps auto focus camera with AF assist beam firing light.
- - The movement of the object to be photographed also affected, if the object moves too quickly it is difficult for the camera to lock focus.
In addition to pressing the shutter button halfway, the camera is a serious class as prosumer cameras and digital SLR cameras, there is the AE-L / AF-L that can be used to lock the focus. AE-L stands for Auto Exposure - Lock, while AF-L stands for Auto Focus - Lock. in settings further, this button can be customized into several functions, such as exposure and focus lock as well, or just lock the exposure, focus lock it, and lock the focus during this button is pressed (AF lock-hold). Choose which one best suits your wishes.
Initially known as auto focus, the camera simply choose the midpoint of the object image as a reference focus. This turned out to be difficult when the objects are not actually in the middle area of the photo. So it then made the zone of focus or focal point spread in some areas of the photo. Generally, there are now at least three zones, namely focusing middle zone (main), left the zone and right zone. The more powerful the more the camera focal zones are available so that they can be more flexible and avoid mistakes locking focus. Special modules on DLSR camera AF, the AF point can be any cross-type sensors aka cross-type sensors. Such sensors are sensitive to differences in contrast both vertically and horizontally. The central AF point is certainly manifold cross type, while the other point is not necessarily. The more diversified cross-type AF points, and the more accurate the more expensive DSLR camera is in focus.
In addition to the focus zone, there are now more options on the camera auto focus mode, the servo AF mode option. Options are stationary or continuous, and adapted to the conditions of the object to be photographed. Stationary mode is chosen for stationary objects, and these tend to be the default mode on most cameras. Continuous mode will detect the movement of objects and try to continue to follow wherever the object moves. Currently DSLR camera was able to lock focus on a moving object left or right forward backward (3D tracking AF).