I'd love to understand just how Nikon, Sony, Canon, etc process the data stream for focus, just from an engineering perspective, though that knowledge may help getting the best out of their systems. The basics of contrast and phase detect AF are pretty well understood, but the the key in...
Camera Module 3 introduces powered autofocus support for the first time. The lens assembly is mounted on a voice-coil actuator, allowing us to move it backwards and forwards relative to the sensor until a selected area (by default the middle) of the scene is optimally focused. Here’s Brian...
Autofocus sensors are essentially complex arrays of light-sensitive strips, and pairs of strips can detect when focus is "out of phase". Some sensors only detect phase shift in one direction, some in two, some in two diagonal directions, each with successively higher sensitivity to contrast diff...
even with phase detection , so if it can’t find some form of contrast to use as a point of reference, it battles. Single point doesn’t give it much area to look for contrast, so small single point will be worse than big single point. Whilst this method is the most accurate, it’...
Along with allowing the lenses to lose some weight, the system could help improve autofocus speeds. Current contrast detection lens parts have to move farther than those inside of a DSLR lens with phase detection. But, by creating a focusing unit that doesn’t require as much movement to focu...
which introduces a slew of issues. Not only would Zeiss have to offer service to calibrate autofocus on lenses, but there are also other problems with phase-detection such as focus shift, which is often a problem with most lenses. Mirrorless Sony and Fuji cameras use contrast detection autofocu...
Sony also says the hybrid autofocus system is 30-percent faster, thanks to a new 117-point focal plane phase detection AF sensor with 25 contrast detection AF points; the A7 II is also 1.5 times more accurate subject tracking than the A7, due to new subject-distance-detection and motion-pr...
However, it cannot achieve non-delay C-AF because the re-focusing process starts only when the current phase state is determined to be out of focus. Contrast-based passive AF utilizes focus search methods to progressively adjust focus [37]. Although predictive algorithms such as depth from ...