Analysis of information sources in references of the Wikipedia article "Four Thirds system" in English language version.
The key difference between contrast-detection autofocus (as generally used in compacts and mirrorless cameras), and phase detection (as traditionally used in DSLRs) is that phase detection is able to assess how out-of-focus the image is, and determine directly how far and in what direction the lens needs to move its focus group to achieve a sharp image. Contrast detection has to scan through at least part of its focus range to find the point of optimal focus.
This difference totally changes to the way lenses need to be designed - those optimised for phase detection need to be able to race to a specified location very quickly, whereas contrast detection lenses need to be able to scan back and forth very quickly. Traditionally, very few lenses designed for phase detection have coped very well with the subtle, scanning motion required for contrast detection. Those designed for Four Thirds SLRs could autofocus on previous Micro Four Thirds cameras, but only slowly and hesitantly.
Details of the Four Thirds System standard are available to camera equipment manufacturers and industry organizations on an NDA basis. Full specifications cannot be provided to individuals or other educational/research entities.
{{cite journal}}: Cite journal requires |journal= (help){{cite journal}}: Cite journal requires |journal= (help)Details of the Four Thirds System standard are available to camera equipment manufacturers and industry organizations on an NDA basis. Full specifications cannot be provided to individuals or other educational/research entities.
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