Hi Jeff,
that is what I understand from the difference between phase detection and
contrast detection. Phase detection delevers information about where
sharpness is to be expected, while contrast detection only informs about
'there is quite a contrast here, but it could be bigger when focussed
elsewhere'. Of course they are investing heavily in the algorithms to
improve this (and I think they are almost there already).
And there is another reason why 43 lenses will never be as fast as m43
lenses, and that is the size of the lens group to be moved while focussing.
m43 lenses are designed to have that group as small as possible, making it
quiet and fast to move (several times in quick succession). Actually, I
understood that the main difference in AF speed between the first m.zuiko
14-42mm and type II/R was that Olympus succeeded in getting this group
substantial smaller. Buying a type II lens is the cheapest way to upgrade
AF speed on the e-p1/2 or e-pl1... (look for the 'msc' label)
Best, Frank.
2012/7/5 List, OM <om-list@xxxxxxxxxxx>
> Thanks Frank,
>
> Trying to understand this ... the 4/3 lens is designed to go to a specific
> position on command rather than focus in the chosen direction until told to
> stop. The m4/3 camera can't give it a position to go to, only tell it to
> stop when it gets there ... ?
>
> That would be consistant with the noise it makes ... a series of
> steps. When the 4/3 lens is on a m4/3 camera it can only make a series of
> small steps. When the 4/3 lens is on a 4/3 camera it takes a large step,
> then may take a smaller step to achieve focus.
>
>
--
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