Archived posting to the Leica Users Group, 2000/11/04

[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]

Subject: Re: [Leica] Focus thread
From: Martin Howard <howard.390@osu.edu>
Date: Sat, 04 Nov 2000 23:59:36 -0500

Austin Franklin jotted down the following:

> The autofocus systems are one, not guideable, two, have an angle of view, and
> three typically require some contrast.

How does that differ from the rangefinder patch in the M?  It's not
guideable other than pointing the whole camera and lens at whatever you wish
to focus.  It has an angle of view equal to the width of the patch, and it
not only requires some contrast, but the subject has to be free of repeating
patterns.  Try focussing it on the repeating pattern of flock wallpaper from
1.5 meters away, a trellis, a uniform fence, corrugated sheet metal, or any
number of other repeating patterns.

Nevertheless, none of the above has anything to do with Jim's assertion that
autofocus is no good because the programmer who wrote the code for the chip
doesn't know what you're going to take a picture of.  Again, it has about as
much relevance as the statement that the guy who paints the shutter speed
numbers on your Leica doesn't know if it's a sunny day or raining when
you're taking pictures at your daughter's graduation.

M.

- -- 
Martin Howard                     |
Visiting Scholar, CSEL, OSU       | If you have to drink and drive, make
email: howard.390@osu.edu         | it a latte...
www: http://mvhoward.i.am/        +---------------------------------------