I set the center focus sensor on my D100 as well, but am thinking
about changing it back. I saw a really interesting discussion that
showed the errors in focus using a center focus device. Most of the
time it is not noticeable, but if your your desired center of sharp
focus is off center, which it usually is, the distance to the subject
will be off. For instance if the focused distance is 10 feet and you
reframe you now have a plane of focus 10 feet away and the off center
subject will be in front of the plane of focus. Trigonometry. It
does not make any difference in most shots because of depth of field,
but it will certainly explain why that eye is not sharp in a portrait
or why that macro shot looks different than you remembered it. I
think that is why some photographers on the list some time ago went
to all matte screens on their OMs, so they would not be fooled into
using the center focusing aids.
The reason for so many focus points is not to completely take you out
of the equation. Some camera makers call the 4 way rocker switch on
the back of the camera the "Focus point selector". It is your way of
selecting your sharpest point of focus in the picture.
Winsor
Long Beach, California, USA
On Aug 24, 2005, at 10:22 AM, alfredo pagliano wrote:
>
> I agree completely
>
> Simpy cannot understand al those AF points on modern DSLRs.
>
> Someone uses them though...
>
>
> On Aug 24, 2005, at 3:30 PM, Walt Wayman wrote:
>
>
>> Scott,
>>
>> The autofocus setting was the first thing I changed on my E-1. In
>> fact, I had made up my mind to do so before I even got my hands on
>> the
>> camera. Before I bought, I downloaded the manual from the Oly
>> website, and upon reading "Normally, the camera measures the distance
>> to the subject using the 3 AF frames in the viewfinder and selects
>> the
>> most appropriate point," my immediate response was, "Bulls**t!
>> I'm in
>> charge here and I'll be the one deciding what's the most appropriate
>> point."
>>
>> So, before I took even the first shot, I set the autofocus to the
>> center frame only, and that's where it's going to stay. And this is
>> even more fitting now that I've changed to the Katz Eye screen, which
>> doesn't have all those little rectangles, just a split prism with a
>> microprism collar, a lot like what I see in the viewfinder of an OM.
>>
>> And, of course, being in control at all times requires that
>> simultaneous AF and MF modes be set so the human in charge has the
>> authority to occasionally fine tune the auto focus, whether it needs
>> it or not, as a reminder to the little man in the camera about who's
>> really the boss of this outfit. You don't want him getting too
>> uppity. :-)
>>
>> Walt
>>
>> --
>> "Anything more than 500 yards from
>> the car just isn't photogenic." --
>> Edward Weston
>>
>> -------------- Original message ----------------------
>> From: "Scott Gomez" <scott@xxxxxxxxxxxxxxxxxxxxxxxxxx>
>>
>> [snip]
>>
>>> First, the autofocus is making me nuts. It's not at all clear to me
>>> how
>>> one tells just what the hell it's focusing *on*. From the manual, it
>>> appears that there are three "focus zones" outlined in the
>>> viewfinder,
>>> any one of which is selected by the E-1 as the focusing point.
>>> There's a
>>> little viewfinder doohickey that even shows you which of the three
>>> targets was used (I've updated to firmware version 1.4; I believe
>>> that
>>> the feature was added in firmware ver. 1.3). However, depending
>>> on the
>>> scene being photographed, the zone encompassed by any one of the
>>> focus-outlines can be a target-rich environment. Just how does one
>>> know
>>> where the actual focus is, with any reliability? What are the
>>> pitfalls
>>> of forcing the camera to use only one focusing zone (as it
>>> appears is
>>> possible to accomplish through settings)? Having *never* extensively
>>> used a camera having autofocus, I'm finding this quite frustrating.
>>>
>>
>> [snip]
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