on 04/18/02 07:57, Stephen Moore opined:
> The MZ-S is the top-of-line AF body, with the latest,
> fastest, most evolved version of the SAFOX system, right?
For a Pentax, fes. But a few development steps behind the other makes. Most
likely to keep the price down, it has no eye-tracking to 18 different focus
points. But it does have the brains to select what "it" thinks is the most
appropriate point in the image to focus on (the closest, most likely).
> Spec sheets, reviews in magazines, mention it has two auto-
> focus modes. From that I infer that the camera is pretty
> straight-ahead, AF-wise. Does that mean "very good but
> maybe Spartan" in terms of features?
Simplicity of design & human interface is more polite.
> From what I've gathered reading the list, some of the other
> bodies (with older SAFOX) can do more "tricks." For example,
> can somebody explain in words of few syllables what "trap
> focus" means, and how important it is? What about "predictive
> AF" and "focus confirmation?" Are these more properly referred
> to as functions of programming rather than characteristics of
> the AF system itself?
Trap focus means the camera is prefocused, you are holding the shutter
button down, and the camera will not fire until something enters that focus
plane, and I believe it has to also be in one of the AF rectangles as well.
Predictive AF is when you are panning or tracking a subject coming toward
you or away from you. The camera takes the shutter delay into account and
prefocuses on the point it calculates the object will be when the shutter is
open. Easily fooled by race cars braking, accelerating, or a subject running
into a brick wall. But as indicated in the manual, runners jogging, brides
parading, or planes falling out of the sky would be handled well, as long as
they remain at the same speed. Camera must be in sequential firing mode. It
will NOT predict your subjects movement in single shot mode.
Focus confirmation is a small hexagon in the finder that lights up when the
AF system senses best focus for a subject. It can also beep at you if you so
choose.
This Is really all the same thing, just utilized in different ways. The AF
sensor tells the system (or you) when it reads the least diffraction of an
edge between light and dark, or lighter and darker. The less difference
between the two, the harder it is for the sensor to read. And in the case of
the PZ and SF series, the closer to that density edge being at right angles
to the focus area, the easier it is to lock in fast. Of course, the same is
true of the newer SAFOX IV cameras, it's just that they have sensors
oriented in both horizontal and vertical, so when pointed in the right
direction, thay can do one or the other well, sometimes both if the subject
covers two or more sensors.
>
> What other features exist, and how important?
Zooming during exposure, with preset start and stopping points, and 3 speeds
of zooming, for never used special effects. You can make a F1 car sitting on
the grid look like it's going top speed towards you though, even with no
driver! It's been used 3 times professionally so far, globally, and is
therefore "last years" fun. Not needed.
>
> I suppose what I'm really asking for is advice on how to
> *think about* moving to the AF world, and to decide what's
> going to be right for me. Help! Please!
If you hate removing your glasses all the time to get close to the finder,
or spending big bucks to have all your cameras have a corrective optic on or
built into your finder system, AF is great. I know. With my LXs and PZs, I
have to adjust the diopter to suite me. On the older cameras and my 67, I
have to try to track down the correct diopter to install over the finder
window. Or like last weekend, I produced 2 rolls of "slightly soft"
exposures. Not to worry though, it was a comp job. Youse gets what you pay
for in this world! <grin>
JoMac, Pentaxian
"Pentax, Quadraphonic, Betamax, Macintosh"
and above the rest.
k t,
s e n
Living life a w o
almost parallel to, r
yet ever so slightly o u t -------> f
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