Sunday, 2 July 2017

filters - Circular Polarization and Passive autofocus



Couple of weeks ago, I was assigned a homework in one of my Applied Physics master's course. My professor asked to explain why passive autofocus works only with circular polarizers.


I am not a very experienced photographer(I still haven't bought a DSLR...) but in my compact cameras I don't think that a special polarisation is needed.


Later I thought, that this is because my cameras use active autofocus. I tried to gather as much information as possible on how passive autofocus works, but I haven't found any indication on whether they need circular polarisation.


Is this statement true? Does autofocus require circularly polarised light to work? Why only passive AF systems are polarisation sensitive?


How is the AF system affected by the polarization of the incident light? This has to do with the censor itself?




No comments:

Post a Comment

Why is the front element of a telephoto lens larger than a wide angle lens?

A wide angle lens has a wide angle of view, therefore it would make sense that the front of the lens would also be wide. A telephoto lens ha...