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Re: [OM] John Hermanson intro for the OM newbies

Subject: Re: [OM] John Hermanson intro for the OM newbies
From: Ken Norton <ken@xxxxxxxxxxx>
Date: Mon, 18 Jun 2012 09:29:26 -0500
As far as the camera is aware, it actually is the closest thing. When you
manually select a focus point, you are telling the camera that that spot in
the viewfinder is the subject and to base any "matrix" or center/surround
exposure calculations on it.

Let's use a specific example. I am photographing a person (upper body shot)
where they are standing in the shade, but the background is bright sunlit
scene, You frame and half-press. The camera will ignore the background and
establish the exposure on the part of the scene associated with the focused
spot. However, if you are using fill flash, the exposure is determined
based on the background and then the subject itself is lit by the flash
using either distance information or via the pre-flash.

The IS series used distance information. Minolta used either distance or
pre-flash. In fact, Minolta was using distance-aware autofocus lenses
before anybody else in SLRs.

The AF control logic in our cameras today have a lot of intelligence to
them in making guesses to keep from being easily fooled. That's why you
rarely see the focus rack all the way in and out whenever we take a
picture. The camera takes into account the brightness of the scene and
sometimes the colors in the scene to make assumptions about the
photographic conditions.

As to face and eye detection, there is a company that has developed this
technology and licenses it to the various camera manufacturers.

AG



>
> On the E-3, I often have the focus sensor reduced to just one spot. It's a
> very narrow focus. I can make it focus through a screen of leaves etc to
> make whatever it hits, to be the "in-focus" thing.
>
> Definitely not always the most close to the camera
>
>

-- 
Ken Norton
ken@xxxxxxxxxxx
http://www.zone-10.com
-- 
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