One of the top features to see out for on acamerathese days is PDAF or form spotting autofocus .
Keep read to larn everything you need to sleep together about PDAF , including what it is , how it act and how it compare to conventional contrast detection AF .
What is PDAF?
PDAF is an autofocus technology that is both faster and more accurate than conventional contrast catching autofocus . The acronym PDAF stand for phase detection autofocus .
The way that phase detection AF works is n’t particularly gentle to get your fountainhead around . Nevertheless , it ’s deserving sympathize how these sensors work in purchase order to get the most out of your television camera .
To put it only , form detection AF works by splitting the prototype your camera run across into two separate images . This is done by using the prism already discover in aDSLRor on - sensor for those shooting with amirrorless television camera . The camera can tell apart if an ikon is in focal point based on whether or not the two image are lined up – or in phase – with each other .
The camera also knows which split effigy is which . If it detects that the two images are out of phase , the camera will use this information to tell the lens which way to move to put the image in nidus .
Canon explains how PDAF exercise in its DSLRs and mirrorless camera in more technical termson its site :
“ Each picture element on the Dual Pixel CMOS sensor has two independent photodiodes ( the parts of the detector that phonograph recording light intensity or smartness ) . The camera ’s processor compares the signal from the two photodiodes , and if they jibe , it knows that this area of the image is in focus . If there is any deviation between them , it looks at pairs of photodiodes across a chemical group of pixels , and can then calculate which direction the lens take to be adjust to reach acute focal point , and how much focal point adjustment is required ” .
All of the above happens in a matter of millisecond , shit the autofocus process quite a turn quicker than contrast spying AF , a method acting that uses contrast to regulate which section of an image want to be sharp and adjust the focus from there .
Contrast catching AF can still be very accurate , but it does n’t equate to phase detection when it come to hurrying , pee-pee PDAF the superior selection for tracking fast - moving subjects and keystone for sports and wildlife photography .
PDAF is also the stronger alternative for abrupt shifts in focus , like move the focus point in time from an objective at the front of the frame to one at the back , or vice versa . Using PDAF makes this transition much smooth and snappier than doing so using dividing line sensing AF .
