did anyone try this: cheap point-n-shoot on the back of a large format beast?

Roland Karlsson wrote:
Leonard Evens wrote in
:


When you start talking about light from distant
galaxies, I think it gets more complicated than just using geometric
optics.


It is the other way around. It is when looking at small things
that geometric optics fails. Even a gravitational lens follows
the laws of geometrical optics - in curved space time

Well I guess it is a matter of semantics. As I understand the term,
geometric optics applies to optics in a Euclidean three dimensional
space. But I suppose there is an extended theory which takes into
account the curvature of space as in general relativity.



Maybe even stuff that hasn't happened yet :-)

Well, when things have happened can be pretty complicated because of
relativity theory. But who knows?


There is a stringent definition of cause and effect in relativity theory.
You can talk about things that have not happened yet. Different
observers cannot in general agree upon when things happen. But if
I drop a crystal vase I can say that it has not hit the floor yet,
and all observers that see me dropping the vase will say the same.
Later, when the vase is spread all over the floor in small pieces,
everyone that sees the mess knows that it is after it has hit the
floor. But they can all see that I have not cleaned up the mess,
that has not happened yet. Of course, the observers will have a totally
different view on how long time the vase took to fall to the floor
and we can never agree upon when it happened; at least not if we
insist on using our own clocks. But if everyone used my clock and
everything happened where I am, then we could all agree upon the
order and timing of all events. But ... that is not the way it is

Your description applies in the context of special relativity. I would
have to read Brian Greene's book again, but it was my impression it
might be a bit more complicated in the context of general relativity
with wormholes. I thought that some physicists envisioned the
possibility of time travel to the past, but perhaps not in a way whereby
one could interact with oneself. Of course, in that context, it is not
even clear what the past is. Perhaps it refers to an earlier epoch
since the big bang. Greene has a whole chapter devoted to time travel,
but I was falling asleep by the time I got to that point.



/Roland

Roland Karlsson wrote:
Leonard Evens wrote in
:


When you start talking about light from distant
galaxies, I think it gets more complicated than just using geometric
optics.


It is the other way around. It is when looking at small things
that geometric optics fails. Even a gravitational lens follows
the laws of geometrical optics - in curved space time

Well I guess it is a matter of semantics. As I understand the term,
geometric optics applies to optics in a Euclidean three dimensional
space. But I suppose there is an extended theory which takes into
account the curvature of space as in general relativity.



Maybe even stuff that hasn't happened yet :-)

Well, when things have happened can be pretty complicated because of
relativity theory. But who knows?


There is a stringent definition of cause and effect in relativity theory.
You can talk about things that have not happened yet. Different
observers cannot in general agree upon when things happen. But if
I drop a crystal vase I can say that it has not hit the floor yet,
and all observers that see me dropping the vase will say the same.
Later, when the vase is spread all over the floor in small pieces,
everyone that sees the mess knows that it is after it has hit the
floor. But they can all see that I have not cleaned up the mess,
that has not happened yet. Of course, the observers will have a totally
different view on how long time the vase took to fall to the floor
and we can never agree upon when it happened; at least not if we
insist on using our own clocks. But if everyone used my clock and
everything happened where I am, then we could all agree upon the
order and timing of all events. But ... that is not the way it is

Your description applies in the context of special relativity. I would
have to read Brian Greene's book again, but it was my impression it
might be a bit more complicated in the context of general relativity
with wormholes. I thought that some physicists envisioned the
possibility of time travel to the past, but perhaps not in a way whereby
one could interact with oneself. Of course, in that context, it is not
even clear what the past is. Perhaps it refers to an earlier epoch
since the big bang. Greene has a whole chapter devoted to time travel,
but I was falling asleep by the time I got to that point.



/Roland

Leonard Evens wrote:

Mark M wrote:

The light must be bent toward the tiny confines of the sensor, or you'll
get nothing but a tiny piece of the image...which would basically appear
big blurry light.

You are basically right, but the tiny image isn't blurry. Try it.



If the digicam can focus on it. The kind he's talking about would have no
chance of doing that.

--

Stacey

chibitul wrote:
Did anyone try to use a large format camera to get an image (with all
the advantages of large format cameras: tilt, shift, etc) and then use a
small digicam instead of film to snap the picture? I imagine if you make
some sort of fixture to attach the digicam to the back of the large
format camera, and focus on the glass plate, you should be able to snap
*that* image. I never used a large format camera and I do not intend to
venture into this field unless I can do it digitally. I am not into high
resolution stuff, I read some of Ansel Adams books and I am impressed
with what you can do with large format when you can tilt/shift the lens
and the negative as you want. Just wondering if I can "piggy-back" a
cheap point-n-shoot on the back of a large format beast?

You mean like this:

http://clarkvision.com/photo/large-f..._7449b-900.jpg

then zoomed in:
http://clarkvision.com/photo/large-f..._7446b-600.jpg

I had to carefully stretch the image in the
ground glass versus the scene, as the image is dark (on
the ground glass). It was quite visible on the original
digital file. But there is no advantage image wise
to do this. It does not give you any more resolution
than inherent in a direct image with the digital camera.

I often photograph my setup to show the movements I use.

I also use my Canon 10D as a backup (before that Canon Elans
with film) to the large format, photographing the scene
in one frame as well as zoomed in to make a mosaic. I also use
the digital camera as a light meter for the 4x5 (I mentally
have to drop the film speed as I use ISO 50 velvia on the
large format and compensate for the f/stop difference,
e.g. typically f/32 to f/45 on the large format).
The large format images are absolutely awesome compared to
any digital, however, so when I have the time I use
the large format.

By the way, that's a 500mm f/4 telephoto (for the canon)
for wildlife in the first frame. I got a number of birds
in the scene with the large format (not in the above; I shot
the camera setup during a dull moment). Day hikes with the
4x5 and 500mm plus other gear = 75 pound pack (I don't do that
much). If you left the gear in the car, you can't get the
shot, and hey, it's exercise!

Roger Clark
Photography, digital info at:
http://clarkvision.com

chibitul wrote:
Did anyone try to use a large format camera to get an image (with all
the advantages of large format cameras: tilt, shift, etc) and then use a
small digicam instead of film to snap the picture? I imagine if you make
some sort of fixture to attach the digicam to the back of the large
format camera, and focus on the glass plate, you should be able to snap
*that* image. I never used a large format camera and I do not intend to
venture into this field unless I can do it digitally. I am not into high
resolution stuff, I read some of Ansel Adams books and I am impressed
with what you can do with large format when you can tilt/shift the lens
and the negative as you want. Just wondering if I can "piggy-back" a
cheap point-n-shoot on the back of a large format beast?

You mean like this:

http://clarkvision.com/photo/large-f..._7449b-900.jpg

then zoomed in:
http://clarkvision.com/photo/large-f..._7446b-600.jpg

I had to carefully stretch the image in the
ground glass versus the scene, as the image is dark (on
the ground glass). It was quite visible on the original
digital file. But there is no advantage image wise
to do this. It does not give you any more resolution
than inherent in a direct image with the digital camera.

I often photograph my setup to show the movements I use.

I also use my Canon 10D as a backup (before that Canon Elans
with film) to the large format, photographing the scene
in one frame as well as zoomed in to make a mosaic. I also use
the digital camera as a light meter for the 4x5 (I mentally
have to drop the film speed as I use ISO 50 velvia on the
large format and compensate for the f/stop difference,
e.g. typically f/32 to f/45 on the large format).
The large format images are absolutely awesome compared to
any digital, however, so when I have the time I use
the large format.

By the way, that's a 500mm f/4 telephoto (for the canon)
for wildlife in the first frame. I got a number of birds
in the scene with the large format (not in the above; I shot
the camera setup during a dull moment). Day hikes with the
4x5 and 500mm plus other gear = 75 pound pack (I don't do that
much). If you left the gear in the car, you can't get the
shot, and hey, it's exercise!

Roger Clark
Photography, digital info at:
http://clarkvision.com

Leonard Evens wrote in :

Your description applies in the context of special relativity. I would
have to read Brian Greene's book again, but it was my impression it
might be a bit more complicated in the context of general relativity
with wormholes. I thought that some physicists envisioned the
possibility of time travel to the past, but perhaps not in a way whereby
one could interact with oneself. Of course, in that context, it is not
even clear what the past is. Perhaps it refers to an earlier epoch
since the big bang. Greene has a whole chapter devoted to time travel,
but I was falling asleep by the time I got to that point.


OK - worm holes and time travel. Nice things to speculate about.
But worm holes is just a possible solution to the equations
used in general relativity. There is nothing that says that
all solutions to those equations must be possible to realise
in the physical world. For worm holes to exit there are three
requirements.

1. There must be black holes - VERIFIED!
2. There must be white holes - none seen, none found, ...
And those things should be visible, I assure you ...
3. There must be some kind of path from a black hole
to a white hole - hard to understand how a stable path
could exist and even be created in the first place.

So . forgetting about worm holes - the law of causiality is still
valid in general relativity theory. No time travel in sight (yet?).


/Roland

Gregory Blank wrote:
: In article ,
: (Argon3) wrote:

: Does anyone remember that 4X5 or other LF transparencies can be SCANNED and
: are
: then DIGITAL and can be played with accordingly? Are there really folks out
: there who have so much time on their hands that they have to find Rube
: Goldberg
: solutions to simple problems or have some folks just become so hung up on
: digital that they just can't think in any other terms?
: argon

: Yes some of us actually print our work with "gasp" enlargers. But I will
: share a little secret I've come up with.......scan 4x5 images, ink jet
: print them them photograph the ink jet prints with 35mm for gallery &
: show submissions. It saves me a ton of time (and Money).

Real photographers use film the size of the final print and then contact print.
:-)
--




Keep working millions on welfare depend on you
-------------------

In rec.photo.equipment.large-format Mark M wrote:

: "chibitul" wrote in message
: ...

: yes, that is what I mean. Most cameras have a macro mode, but you can
: also put the camera about 0.5 meters away from the ground glass.
:
: Ok, the image is dim, but this is large format camera here, not sports
: or action. we're talking landscapes, biuldings, etc, right? what's wrong
: with a slow shutter speed?
:
: And do you really need the ground glass? what if you *remove* the ground
: glass, the image will act as an object for the digicam. it should work.

: How will the "image act as an object" without the glass?

I was wondering that myself. Without the ground glass there is no image.

--




Keep working millions on welfare depend on you
-------------------

In rec.photo.equipment.large-format Leonard Evens wrote:
: Mark M wrote:
: "chibitul" wrote in message
: ...
:
:
: yes, that is what I mean. Most cameras have a macro mode, but you can
: also put the camera about 0.5 meters away from the ground glass.
:
: Ok, the image is dim, but this is large format camera here, not sports
: or action. we're talking landscapes, biuldings, etc, right? what's wrong
: with a slow shutter speed?
:
: And do you really need the ground glass? what if you *remove* the ground
: glass, the image will act as an object for the digicam. it should work.
:
:
: How will the "image act as an object" without the glass?

: It won't, but there is an aerial image there even without the gg. Take
: off your gg if you can and use a magnifier or loupe to look at where it
: was. You will see an image. But you have to point the magnifier in
: the right direction. If you don't do that, I'm not sure what you get;
: probably extremely diminished intensity.

I may not know what I'm talking about but wouldn't you then need a lens on the
P&S that's 4x5??

--




Keep working millions on welfare depend on you
-------------------

In rec.photo.equipment.large-format Leonard Evens wrote:
: Mark M wrote:
: "chibitul" wrote in message
: ...
:
:
: yes, that is what I mean. Most cameras have a macro mode, but you can
: also put the camera about 0.5 meters away from the ground glass.
:
: Ok, the image is dim, but this is large format camera here, not sports
: or action. we're talking landscapes, biuldings, etc, right? what's wrong
: with a slow shutter speed?
:
: And do you really need the ground glass? what if you *remove* the ground
: glass, the image will act as an object for the digicam. it should work.
:
:
: How will the "image act as an object" without the glass?

: It won't, but there is an aerial image there even without the gg. Take
: off your gg if you can and use a magnifier or loupe to look at where it
: was. You will see an image. But you have to point the magnifier in
: the right direction. If you don't do that, I'm not sure what you get;
: probably extremely diminished intensity.

I may not know what I'm talking about but wouldn't you then need a lens on the
P&S that's 4x5??

--




Keep working millions on welfare depend on you
-------------------