Hi--

>Thanks for the response ... I'm still not really clear on how the camera
>makes its decisions, though.

No mystery - the instruction book gives the shutter speed/aperture
select "curve", which is more specific than what I said, but you can use
what I said to find the apertures corresponding to the shutter speeds.
The whole "curve" is moved up or down depending on light level/film speed.
In other words at a certain light level, with a certain film speed, the
camera may select 1/125th at f2.8 instead of 1/500th at f5.6, or some such.
(The "curve" of aperture/shutter speed combinations is linear until aperture/shutter speed limits are reached.)

>Bob Neuman writes:
>> In program mode, both aperture and shutter speeds are selected by the
>> camera. As the light level increases, ever smaller apertures and faster
>> shutter speeds are selected. The shutter speed is shown in the VF (two
>> lights indicates an inbetween speed). To find out what aperture is being
>> used, move the aperture ring from the minimum f-stop (normally selected
>> for program mode) until the fault lights alternately blink in the VF,
>> indicating that you have selected an aperture slightly wider than the
>> one the camera would select, but which it cannot now use. "P" has the
>> disadvantage of usually using a wider aperture/faster shutter speed
>> combination than I would normally select for lenses shorter than about
>> 105mm. "A" and "M" modes avoid this problem.

>Does that mean that "P" mode will try to maximize aperture/minimize
>shutter speed, i.e. it will use the widest aperture it can unless that
>would require a shutter speed faster than 1000, in which case it will
>use 1000 and stop down the aperture?

No - it follows a relationship between aperture/speed, unless the camera runs out of one or the other, in which case it changes only the one
that still has changing room. My complaint about P is that the curve
chosen generally keeps the aperture wide-open too long, until an
unnecessarily high shutter speed is reached, like 1/250th maybe, after
which both change - this does not optimize sharpness or DOF, and is
designed to cover shaky hands/longer than normal lenses (results in poor choices for normal/wide-angle lenses, though).

>(That's one of my basic algorithms when shooting with my slow, long
>lens, so if that's what "P" does, I'll definitely start using it
>on occasion.)

Unless the lens is unusually good wide-open, and you are very good at focusing, you will not get the best sharpness this way....

>> BTW, AI'd, AI, AIS, E,
>> and AF lenses will all work in program mode on the FG. Others have
>> explained how this is done.

>Any idea where I might be able to find these explanations? I've been
>reading all the rec.photo groups for about 3 months now, and have seen
>at least 4 different people ask about the FG program mode, and have never
>seen anyone explain it (which is why I finally posted). I'm glad to
>hear that AI'd lenses will work, since I have a 24mm Nikkor that I'm
>thinking of getting AI'ed, and and it would be nice to know that it
>would also work in "P" mode.
> ...Akkana akkana@best.com
> http://www.best.com/~akkana/

They are in adjacent posts, about how the camera samples the stopped down image before exposure and changes the speed to fit any aperture error detected.
David Ruether