Hey guyz, In this blog I will be discussing with you
HOW A CAMERA FOCUSES AUTOMATICALLY
In the split second between the pressing
of the shutter release and the opening of the shutter, an automatic camera
measures the distance between the lens and the subject and positions the lens
to give sharp focus.
Most compact cameras have a tiny electric motor driving a transmitter
that emits a beam of infrared light.The transmitter is linked to the lens ,
which moves in or out as the beam scans – focusing from near to far. The beam
reflects back from objects to the camera , and stops the transmitter when the
strongest signal shows that the lens is in focus. This automatically triggers
the shutter.
Some instant cameras have ultrasonic focusing similar to the
echolocation scanning system bats use to navigate. A gold-plated disc(the
transducer) sends out ‘chirps’ too high to be heard by human ears, each lasting
1/1000th of a second. The disc receives the chirp echoes from the
subject, time each chirp takes to go out and come back. From this it calculates
the distance to the subject.
SLR(single-lens reflex) cameras with an auto-focus use what is known as
an electronic phase detection system. In this , light entering through the
lens, is separated into two images. A sensor measures the distance between the
two images, which are a specific distance apart when the lens is in focus. If
the distance is not correct, the sensor causes a motor to move the lens.
Thanks
Nymgo
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