DSLR vs P&S a replay of Film vs Digital?

Scott W wrote:

John Navas wrote:

On Sun, 18 Nov 2007 07:05:03 -1000, Scott W wrote
in :

arnold ziffendorfer wrote:


If the "fast auto-focus" admirers only realized how often they
reveal their own
lack of talent and skills at photography. Snap-shooters that have been
brainwashed into thinking that they can buy a camera that will
magically bestow
them with talent. They need to read Jack & the Beanstalk for hints
on how to
find some magic beans while they're at it.

Well now manual focus can work, but it normally does not work well on
a P&S camera. On a P&S you pretty much are stuck with auto-focus, so
it really better work pretty good.


Auto-focus actually does works well on most compact cameras, and any
speed issue is easily overcome with pre-focusing.

The reason manual focus is often omitted from compact cameras is that
most of the target market can't or won't use it. Those that want it can
of course choose a compact camera that has it.



This is the kind of shot where you need a fairly good focus system and
pre-focus simply will not work.
http://www.pbase.com/konascott/image/89149499/original

The boat is moving fast enough that if you try and pre-focus on it the
focus is likely to be off by the time you take the photo.

Now I know you can get a photo like this with a non-DSLR since I have
taken a lot of them, but it is far harder to do.

Scott


Not to mention that "auto" focus can be fooled by things such as
branches, wires etc that are closer than your intended subject.

JT

On Mon, 19 Nov 2007 22:25:21 -0500, "Neil Harrington"
wrote in
:

"John Navas" wrote in message
.. .

Depends on the implementation. Zoom by wire can be faster, since it's
not limited to a 1:1 relationship, it can have multiple speeds

It can have mutiple speeds but not an infinite number of instantly variable
speeds from very fast to extremely slow, all under the photographer's
perfect control. And that's the difference. Two- or three-speed motorized
zooms are extremely crude compared to what you can do by hand.

Continuously variable speed is in fact quite practical, and the essence
of a servo system is that it automatically optimizes acceleration and
deceleration to the control setting by the operator. Such a system is
anything but crude, which is part of why disk drives are so fast.

Yes, with practice you may be able to deal with the shortcomings, just as
with any other less-than-ideal tool. But you still don't get the perfect
control that you do with a manual zoom.

You can actually get better and faster control than manual zoom because
manual zoom is limited to 1:1 linkage and human reaction time, and thus
zooming speed can never be different from control speed, much less
accurately braked. There's a big difference in mass on the control.

For one thing, most if not all motorized zooms change focal length by
*steps*, not really continuously.

The best such systems are already near continuous, and continue to get
more precise.

With such a lens you can get a step that's
"close enough," but that's still well short of the f.l. control you'd have
with fully manual zoom.

The near continuous systems are comparable in resolution to manual zoom
in many cases -- precision is less important for zoom than for focus.

--
Best regards,
John Navas
Panasonic DMC-FZ8 (and several others)

On Mon, 19 Nov 2007 22:15:52 -0500, "Neil Harrington"
wrote in
:

"John Navas" wrote in message
.. .

A sample of two does not a truth make,

I must have over 25 digital cameras, at least 15 being compacts of several
different makes with motorized zoom. You may say "a sample of 15 does not a
truth make" either, but I submit it's enough to give the user a fair idea of
how motorized zoom compares with manual zoom.

Depends on whether they are best of breed or not.
Are you claiming they are?

and motorized zoom on the Canon
Pro1 is better than on your Nikons.

I don't have that model but I do have three other Canons with motorized
zoom. There isn't that much difference between any of them, really. ...

The Pro1 is different. What the others are is irrelevant.
You can't rebut something about A by referring to B.

Fly by wire can be much better than
manual control, as any qualified commercial or military pilot would tell
you.

For military or commercial aircraft, yes. There are reasons for that that
have absolutely no connection with the operation of zoom lenses.

The reasons it's better for aircraft apply to zoom lenses as well,
including faster and more precise response, and control damping.

The "bump in the learning curve" is when a photographer learns how to
use a tool effectively. What matters is the photographer, not the tool.

*Both* matter. It's not an either-or question. Some tools are better than
others.

The difference in mattering between photographer and tool is huge.
Good tools do not make good images, they just make good images easier.

There's nothing inherently "inferior" about motorized zoom, which can
actually be more precise in terms of focus than manual zoom

No way, John. Imagine trying to turn an adjustment screw with a motorized
screwdriver.

Not a valid analogy -- not a servo system.

I'm all for automation where it's of benefit, but there are
some things it's just better to do manually.

Servo systems can easily be better than manual control.

-- it's just
different, as any good photographer knows.

Different and inferior, from the standpoint of speed and accuracy.

Actually superior from the standpoint of speed and accuracy.

--
Best regards,
John Navas
Panasonic DMC-FZ8 (and several others)

"John Navas" wrote in message
...
On Mon, 19 Nov 2007 19:16:58 -0800, "William Graham"
wrote in :

"John Navas" wrote in message
. ..

Your gut is not correct -- see my prior response on fast servo control.

Well, not to worry.

What makes you think I'm worried?

Auto zooming certainly has its place in remote
controlled TV systems and the like. (Moon landers, for example, and
cameras
mounted on the tops of towers and the like)

Power (not auto) zoom also has its place in a multitude of compact
cameras.

...I am simply stating the obvious: That the fewer items that you have
to put in between the operator and the machine the faster and better will
be
the operation.

Obvious or not, it's simply not true, as I've explained.

Then we have to agree to disagree on this....Since the zooming is ultimately
controlled by the photographer, how could putting some automatic mechanism
between the photographers hand and the lens be any advantage? If the item is
too big and heavy to be moved by the strength of the photographers hand,
then there is a need for such a device. If the object is at a remote
location, so the photographer can't be there, then there is a need for such
a device. If returning the zoom position to some precise memorized location
is necessary, then there is a reason for such a device.But if the lens is
easily controlled, and at the same location as the photographer, and no
precise return to a previously memorized location is necessary, then it can
only be a disadvantage to interpose some mechanical device between the two.
That having been said, then why do they do it? - To me, the reason is
obvious. It is a Madison Avenue artifact. First, you convince the public
that what you do is best for them, then they will buy whatever it is that
you do. This is opposed to first finding out what they want, and then going
to the trouble of building it. IOW, it is easier and cheaper to hypnotize
your customers than it is to build something that is actually useful to
them.

"John Navas" wrote in message
...
On Mon, 19 Nov 2007 14:33:25 -0800, "William Graham"
wrote in :

"John Navas" wrote in message
. ..

With all due respect, it's quite possible to have a zoom system with
little or no overshoot, especially since zoom is less critical than
focus. The experienced user anticipates the desired point when using
the control. With distance (not just direction and/or speed) control,
the experienced user can even signal a final point almost instantly,
with speed of response limited only by motor power.

But you have to define the right point to the machine......You can tell
the
camera that you want any given focal length in millimeters, but then you
would have to know what that figure is, and if you don't know that, but
are
just zooming to get a given object to fill 2/3 of your frame, (for
example)
then how are you going to translate that into machine language? IOW, even
if
you know where you want it to be, you have to use "machine speak" in order
to tell the camera where that place is. Otherwise, the machine will have
to
slew slow enough for you to be able to stop it at the right place......I
think that, like your mouse, you should be able to adjust the speed in
software somewhere to find a point where you are comfortable with it, and
this point will vary according to the photographers ability. But the
camera
can never know in advance exactly how far you intend to go as it does with
auto focusing, because the final point can't be defined in machine
language.

Only a crude system would have to depend on a slow slew rate. It's
quite easy to design a fast active servo system with a simple and
effective control input. One possible way is the same as manual zoom.
Someone experienced with manual zoom moves the zoom control to the
approximate desired point by experience, limited by the speed with which
elements can be shifted by the manual zoom control. Turn that control
into fly by wire and it can be moved into position faster, and sensed
continuously in terms of distance and direction by the servo control,
which can accelerate and decelerate the zoom motor on an optimum
acceleration profile, aided by less mass and mechanics due to the lack
of manual zoom connection. At the same time it can automatically
compensate for beneficial nonlinearity (undesirable in a manual system)
and for focus shift (present in even the best zoom optics).

All of which misses the point of what he's saying. Yes, if you knew
beforehand that you wanted a lens to zoom to precisely 127.5mm, or any other
exact f.l., then yes, you could probably engineer an electronic zooming
system that could do that faster than it could be done by hand. But you
would have to know the desired f.l. *beforehand*. Human beings don't
normally use a zoom lens that way. They really on eye-hand coordination to
get *quickly* to the approximate composition, then slow down *quickly* to
fine-tune it to the desired result. The brain is involved through the whole
process and, with a full-manual zoom, quickly and efficiently controls the
whole process. No electronic motorized razzle-dazzle is going to be able to
do what the brain-eye-hand system does, and do it with the same speed and
efficiency.


Such fast
active servo systems are now very well-understood (think disk drives,
and the difference between slow obsolete steppers and current high-speed
servos). Even more sophisticated systems could add control rate
sensing, eye movement, object sensing, etc.

Moving a mouse is analogous once you're comfortable with it, and are not
moving the mouse pointer by watching its entire movement. (You can
easily tell the difference between someone experienced with a mouse, and
someone still feeling it out.) You rapidly move the mouse to the
approximate desired point, and then fine tune from screen position once
you get there, aided by multiple speeds and an acceleration profile.

Because you're doing it *manually*! Your mouse example is actually a good
one. You very quickly, automatically, intuitively, move the mouse to where
you want it. You can do this with great speed and accuracy.

Now suppose you had to move the mouse not via your own eye-hand
coordination, but by using some intermediate motorized device to move the
mouse. Do you really think you could ever move the mouse with the same speed
and accuracy that way?

Neil

"Neil Harrington" wrote in message
. ..

"John Navas" wrote in message
...
On Mon, 19 Nov 2007 14:33:25 -0800, "William Graham"
wrote in :

"John Navas" wrote in message
...

With all due respect, it's quite possible to have a zoom system with
little or no overshoot, especially since zoom is less critical than
focus. The experienced user anticipates the desired point when using
the control. With distance (not just direction and/or speed) control,
the experienced user can even signal a final point almost instantly,
with speed of response limited only by motor power.

But you have to define the right point to the machine......You can tell
the
camera that you want any given focal length in millimeters, but then you
would have to know what that figure is, and if you don't know that, but
are
just zooming to get a given object to fill 2/3 of your frame, (for
example)
then how are you going to translate that into machine language? IOW,
even if
you know where you want it to be, you have to use "machine speak" in
order
to tell the camera where that place is. Otherwise, the machine will have
to
slew slow enough for you to be able to stop it at the right place......I
think that, like your mouse, you should be able to adjust the speed in
software somewhere to find a point where you are comfortable with it, and
this point will vary according to the photographers ability. But the
camera
can never know in advance exactly how far you intend to go as it does
with
auto focusing, because the final point can't be defined in machine
language.

Only a crude system would have to depend on a slow slew rate. It's
quite easy to design a fast active servo system with a simple and
effective control input. One possible way is the same as manual zoom.
Someone experienced with manual zoom moves the zoom control to the
approximate desired point by experience, limited by the speed with which
elements can be shifted by the manual zoom control. Turn that control
into fly by wire and it can be moved into position faster, and sensed
continuously in terms of distance and direction by the servo control,
which can accelerate and decelerate the zoom motor on an optimum
acceleration profile, aided by less mass and mechanics due to the lack
of manual zoom connection. At the same time it can automatically
compensate for beneficial nonlinearity (undesirable in a manual system)
and for focus shift (present in even the best zoom optics).

All of which misses the point of what he's saying. Yes, if you knew
beforehand that you wanted a lens to zoom to precisely 127.5mm, or any
other exact f.l., then yes, you could probably engineer an electronic
zooming system that could do that faster than it could be done by hand.
But you would have to know the desired f.l. *beforehand*. Human beings
don't normally use a zoom lens that way. They really on eye-hand
coordination to get *quickly* to the approximate composition, then slow
down *quickly* to fine-tune it to the desired result. The brain is
involved through the whole process and, with a full-manual zoom, quickly
and efficiently controls the whole process. No electronic motorized
razzle-dazzle is going to be able to do what the brain-eye-hand system
does, and do it with the same speed and efficiency.


Such fast
active servo systems are now very well-understood (think disk drives,
and the difference between slow obsolete steppers and current high-speed
servos). Even more sophisticated systems could add control rate
sensing, eye movement, object sensing, etc.

Moving a mouse is analogous once you're comfortable with it, and are not
moving the mouse pointer by watching its entire movement. (You can
easily tell the difference between someone experienced with a mouse, and
someone still feeling it out.) You rapidly move the mouse to the
approximate desired point, and then fine tune from screen position once
you get there, aided by multiple speeds and an acceleration profile.

Because you're doing it *manually*! Your mouse example is actually a good
one. You very quickly, automatically, intuitively, move the mouse to where
you want it. You can do this with great speed and accuracy.

Now suppose you had to move the mouse not via your own eye-hand
coordination, but by using some intermediate motorized device to move the
mouse. Do you really think you could ever move the mouse with the same
speed and accuracy that way?

Neil

Well, some powered systems are very good. I remember when power steering for
automobiles first came into general use. They were good for parking, but
generally didn't give you the same road feel as direct steering
mechanisms.....Today they are a lot better. So much so that few people even
realize that they are operating a car equipped with them. They feel just
like direct drive at speed, and yet enable you to park without hardly any
effort at all.

"William Graham" wrote in message
. ..

"Annika1980" wrote in message
...


Calling a Crapasonic Lumix lens a "Leica" is kinda like calling a VW
bug a Porsche.

And they've been doing that for 30 yers now......They guy who used to live
around the corner from me back in the 80's showed up with something he
called a "Porsche 914" (If I remember correctly) It was nothing more than
a VW with a sporty looking body hung on it. And the pice of junk I saw in
a drugstore window on Market street in SF had "MacIntosh Amplifier" on it
20 years before that, and I knew that they had sold their name out to some
El Cheapo company then, too. All of my life I have seen good brand names
turn to crap when their owners died, and their kids sold out gramps'
business to the tin merchants. This is what they mean when they say, "Let
the buyer beware".........

Ain't that the truth. I'm old enough to remember when Fisher was a really
high-quality brand in hi-fi equipment. Then somebody else bought the name
and it began appearing on loads of cheap audio stuff and VCRs.

Neil

John Navas wrote:

What exists now works just fine, if you learn how to use it effectively.

You talk like someone who has completely missed the point. AFAICT no-one is
disputing the capabilities of the kind of systems you're describing. But
that's not the problem, the problem is the human interface. For tasks like
zooming or focussing a lens by hand, you're never going to beat precision
grip rotation or sliding with operation by small switches. It's ergonomics,
not control systems, that matters in this case.

On Mon, 19 Nov 2007 19:52:27 -0800, "William Graham"
wrote in :

"John Navas" wrote in message
.. .

It is easily communicated to the camera. (Just because you can't think
how to do it doesn't mean it can't be done.)

Well, much of my zooming is done for compositional reasons, and I don't know
how I could communicate that to the camera....

Servo system based on direction and distance.

I zoom until the picture looks
good, and sometimes go back and forth several times, until I finally make up
my mind. Sometimes I continuously zoom the lens while watching a moving
subject approach my location, and then take the picture when it, "looks
good" for some abstract reason....Such as the subject looking in my
direction, or another object in the background makes for a more interesting
picture, so I zoom it out a little to catch that object too....I couldn't
communicate these things to a machine very well.

Sure you can -- you're doing it now, and what you're doing works just as
well if not better with a good servo system. The essence of good servo
control is that you tell the servo system what you want, and the servo
system does it faster and more accurately than you could do it manually.

It's just a matter of
control, and how to get enough of it to feel comfortable with what I'm
doing.

Again, think of a mouse, and how rapidly and accurately you can move a
good mouse, because of the benefits of acceleration and variable speed
(pointer movement ratio to mouse movement).

--
Best regards,
John Navas
Panasonic DMC-FZ8 (and several others)

"Neil Harrington" wrote in message
...

"William Graham" wrote in message
. ..

"Annika1980" wrote in message
...


Calling a Crapasonic Lumix lens a "Leica" is kinda like calling a VW
bug a Porsche.

And they've been doing that for 30 yers now......They guy who used to
live around the corner from me back in the 80's showed up with something
he called a "Porsche 914" (If I remember correctly) It was nothing more
than a VW with a sporty looking body hung on it. And the pice of junk I
saw in a drugstore window on Market street in SF had "MacIntosh
Amplifier" on it 20 years before that, and I knew that they had sold
their name out to some El Cheapo company then, too. All of my life I have
seen good brand names turn to crap when their owners died, and their kids
sold out gramps' business to the tin merchants. This is what they mean
when they say, "Let the buyer beware".........

Ain't that the truth. I'm old enough to remember when Fisher was a really
high-quality brand in hi-fi equipment. Then somebody else bought the name
and it began appearing on loads of cheap audio stuff and VCRs.

Neil

Yeah....Restaurants are the same way....When the cook dies/retires/leaves,
the place is no longer what you remember it to be, and you will end up
getting one more bad meal to add to your long (for me) list........