Archived posting to the Leica Users Group, 1999/06/08

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Subject: [Leica] Automode a la mode
From: Jim Brick <jimbrick@photoaccess.com>
Date: Tue, 08 Jun 1999 04:16:06 -0700

I think one of the reasons that I'm an old fashioned photographer, is that
I work in the hi-tech computer field. My company (Photo Access) is
designing the chip set for the next generation consumer digital cameras. I
am writing the "firmware" for the chipset. Firmware is what's in all
computer controlled devices. Cameras, phones, cars, microwaves, TV's...
everything. Firmware is software that is at the lowest level. It is what
makes the hardware (chipset) work. Firmware and hardware work hand in hand
to control something. On top of that is application programs (software)
which controls what the user sees and what the user can do.

I am, at this very moment, writing firmware that will control the automatic
exposure mode if whatever digital camera our chips get into. I have 36
zones (I control where they are, how large they are, and how many there are
up to 36.) A 6x6 configurable matrix. I also control the focus by stripping
out pixels during sensor prescans and doing some algorithms that will give
me contrast ratios of edge detection and other numerical tidbits that aid
in focusing.

Understanding how all of this works internally, and having to do it for the
"next generation" leaves little doubt in my mind that human evaluation is
far far superior to computer evaluation. This is why exposures are often
not exactly correct (you'll never know with print film or digital camera),
and why autofocus hunts. Or focuses on the wrong plane (because of some
edge contrast behind the subject.)

Autofocus works well on selected subjects under "normal" circumstances.
These normal circumstances usually mean that the working f/stop will allow
DOF to cover the near misses in AF. The photographer never knows it has
happened. Take an autofocus 300mm lens. Photograph a person, head shot,
backlit, at f/2.8. Typically, the autofocus will focus on the line around
the ears. The contrast between the bright backlight and the dark ear. The
resulting photograph will have sharp ears and out of focus facial features,
like eyes and nose. We all know that when photographing an animal (human or
otherwise), and the face is involved, the eyes MUST be in sharp focus.
Autofocus cannot focus on non-contrasty subjects. Hunting will result. This
is really difficult to solve. But a human can focus on the eyebrows, or
freckles, or whatever. Even at extremely low contrast. When your camera
hunts, you can switch to manual and focus yourself. This is no longer
autofocus.

Likewise, a human can evaluate a scene, determine what is important, figure
out where the highlights belong, set the exposure, and get perfect
photographs. A computer (my - or anyone else's - matrix program) cannot
evaluate a scene in terms of human comprehension. You can direct the "spot"
meter mode to see the highlight (you point the camera there), see the
shadow (you point the camera there), see the midtones (you point the camera
there) and the computer will compute the resulting exposure. This is no
longer autoexposure.

For many many subjects, autoexposure and autofocus work perfectly. The
camera will take the picture for you. But unless you know the science of
photography, you are stuck with photographing only what the camera computer
can comprehend. Anything outside these limits is a crap shoot!

A professional photographer, using autofocus and even autoexposure, is a
different story. A professional knows when it will work and when it will
not work. And when it will not work, the professional knows how to take
command of the situation and get the photograph.

Jim Laurel's use of autofocus is 100% legitimate and warranted. He is a
photographer and can determine, on his own, what makes his job easier and
more secure. But this does not make a market for a Leica autoeverything camera.

In the photography world, there are lots of losses. Nikon loses money on
both it's digital program and it's professional 35mm program (F5, etc.).
It's the amateur 35mm dollars that keep it all going. It's probably the
same with other manufacturers. I know it is this way with all major
companies and their "digital" camera offerings. So what makes anyone think
that if Leica came out with an all encompassing auto camera, even a
re-badged camera, they would succeed? I personally think that Leica has a
formula that works. Basic photographic tools, exquisite lenses. Equipment
for real photographers. Trying to butt heads with established
autoeverything camera manufacturers is futile. Just like it would be futile
for them to produce Leica "like" cameras. There are a few people that will
buy anything, made by anybody. So there would be some glimmer of success.
But not sustaining.

Back to work now...

Jim

PS... while at Keeble & Shuchat's 34th anniversary sale (last Thurs, Fri, &
Sat), I watched the Contax rep demoing the new MF Contax autofocus camera.
It was hunting a lot. And the rep said "when it cannot focus, just push
this button under your thumb, and you can focus manually". This seems
oxymoronic.