cameras focus automatically by detecting contrast. If there's no contrast, there's no water focus. Now I contest this theory by pointing my camera to clear blue sky because there's no contrast in that blue the camel going to what it's called hunt mode, with the lens moving backwards and forwards constantly looking for something to focus on but never actually making a decision. If, however, I point, the camera toe white bird flying through the blue sky in the contrast between the bird in the sky will give the cameras something to focus on our cameras. Sees contrast pretty much depends on the type of camera. DS Alaska it One way Marylise cameras do it another. The two systems are called phase detection and contrast. Detection face detection works off the mirror, which is why it can't be used in a mirror. This camera contrast detection works off the sensor, which is why it can't be using a DSLR because in a DSLR the mirror gets in the way. However, modern technology being what it is, most...
cameras today actually use a hybrid system, a combination of the two, and that's because both of them have advantages. Contrast. Detection is the most accurate, but it's relatively slow and only really good for static subjects such as landscapes. Face detection is much faster and is great for tracking moving subjects. But now we've understood the science of auto focus is your job to tell the camera what to focus on, and you do that Using the auto focus sensors, which are those little squares you see etched in the viewfinder of the layout of the grid, varies between types of camera in DSLR cameras or sensors arranged to cover an area in the center of the viewfinder. While in Marylise cameras, they tend to cover the whole image space. The number of sensors also varies. High end cameras tend to have more, which on the whole means quicker, more accurate. Focusing on this is one of the things you're paying for with a higher price tag. The senses themselves also very between cross type and line type. Now, cross type sensors detect contrast in both vertical and horizontal planes, while line type sensors detect contrast in one plane only which, generally speaking, made cross type senses quicker to focus and more accurate. But only some of the senses in high end cameras. Typically those groups right in the center of the folks in grid across type and an entry level cameras. Sometimes the only cross type center is the middle one, and this is something to be aware off. If your subject dictates speedy auto focus to manually set the active F sensor, that is the sense of the camera starts with. Before tracking any movement, you simply move the focus selector until the appropriate sensor is lit. Then when you turn on auto focus, whatever is covered by the sensor is this subject the camera will focus on. And that brings me to my next question. What object will arian the scene? Do you focus on?