Synchronizing Inexpensive Digital Camera Shutters

Allen wrote on Sun, 12 Aug 2007 14:18:15 -0500:

A Dave Cohen wrote:
?? Pooua wrote:
?? I have not found any stereoscopic cameras that meet my
?? needs, so I would like to assemble something that might.
?? I want to rig two point- and-shoot digital cameras
?? together so they will record a stereoscopic image. The
?? problem is synchronizing the shutters. It should
?? be possible to use one camera for focusing, with the
?? other camera set as a slave. But, I don't know what
?? circuitry would allow for this. Does anyone have any
?? suggestions?
??
?? Thank you.
??
?? I suspect the reason you can't find any stereoscopic
?? cameras is the same reason I have a bunch of 35mm slides
?? that are never viewed, it's a pain to have to use a
?? special viewer but that's just my opinion so no flaming.
?? They used to make stereoscopic film cameras but they seem
?? to have gone out of fashion, again I suspect (but cannot
?? prove) due to viewing problems. Actually, you can train
?? yourself to view two side by side images in stereo without
?? a viewer. I doubt you'll have any luck jury rigging
?? anything except a gizmo that lets you slide the camera and
?? take two shots. Fine for stills. They used to sell an
?? accessory that would put two images on film using a mirror
?? arrangement, but again I haven't seen anything like that
?? recently. Have you figured out how you would view or
?? display the final result. Dave Cohen
A That rings a bell; I have a mental picture of what they
A looked like. Did the late lamented Spiratone sell the mirror
A thing? Soooo many photo gadgets have come and gone over the
A years, some of which should never have gone away, and some
A of which should never have appeared. I wish I still had the
A many years of back issues of Pop Photo, Modern Photo, US
A Camera, American Photo, Camera Magazine that I have disposed
A of. I'd really enjoy going back and looking at the ads.
A Allen

I managed to find my old collection of stereo viewers after
reading this discussion. While searching for sources of stereo
pairs on the web I came across this
http://www.loreo.com/pages/products/loreo_3dcap.html
The date on the URL is 2007 so the products should be available.

It is claimed to work with digital cameras tho' I know nothing
much else about it. The company does also make an inexpensive
viewer. I wish I could find a source of the Hubbard stereo
viewers that I used to use for stereo prints in scientific
journals. They were cheap enough that I could encourage people
to steal them from my laboratory!


James Silverton
Potomac, Maryland

E-mail, with obvious alterations:
not.jim.silverton.at.verizon.not

Dave Cohen wrote:
I doubt you'll have any luck jury rigging anything except a gizmo that
lets you slide the camera and take two shots. Fine for stills. They used
to sell an accessory that would put two images on film using a mirror
arrangement, but again I haven't seen anything like that recently.

Why? It was done with film cameras for decades. Rig up something
that pushes 2 cable releases at one time.

Have you figured out how you would view or display the final result.

Simple: 2 LCD projectors with polarizers at 90 degrees,
then wear polarizing glasses. About a year ago I
attended a stereo slide show that was astounding.
The main issue was 35mm slide projectors are dim, and
you have the polarizers on the projectors and your
head, reducing light levels a lot. LCD projectors
are much brighter which overcomes that problem.

There are (expensive) monitors with built in polarizers that
change polarization fast between two slides, and you wear
polarizing glasses that are synced to the display.
You see 3D quite well with the system.

Roger

"Roger N. Clark (change username to rnclark)" wrote in
message ...


There are (expensive) monitors with built in polarizers that
change polarization fast between two slides, and you wear
polarizing glasses that are synced to the display.
You see 3D quite well with the system.


Don't you mean they had goggles with an LCD shutter in them and the monitor
displayed alternating images which the shutter passed to the left or right
eye as required.
IIRC Imax do that now.

In article , change username to rnclark
wrote:

There are (expensive) monitors with built in polarizers that
change polarization fast between two slides, and you wear
polarizing glasses that are synced to the display.
You see 3D quite well with the system.

sharp made a laptop that had a lenticular 3d screen that did not need
goggles at all. i saw one at a recent camera show and the 3d effect
worked fairly well but it was highly dependent on one's head position.
unfortunately, the laptop itself was big and heavy.

http://www.pcmag.com/article2/0,1895,1386949,00.asp

On Aug 12, 4:27 am, Cliff H. wrote:
On Sun, 12 Aug 2007 01:53:22 -0700, Pooua wrote:
On Aug 11, 11:58 pm, "Frank ess" wrote:

Are the photos you require "action" shots? I have seen rigs for one
camera on a sliding base that can expose two frames within a second or
so.

The reason I want to do this is so I can capture ordinary, natural
shots outdoors. Things like leaves blowing in the wind and water
falling down a waterfall are the subjects I want to capture. They
aren't all that fast, but I can't catch them using a single camera to
take sequential shots. I would like for the shutters to synchronize
within 1/250 sec of each other.

Have you also considered building an optical device that splits a single-frame
down the middle? One could be constructed fairly easily using four small
1st-surface mirrors. Example (view in a fixed-pitch font):

(scene)
| |
| |
\---\/---/
||
(lens)

Angled lines are mirrors, vertical & horizontal lines are the two light paths.

If you do find two digital cameras where you can sync the shutters with a common
electrical shutter-release you'll have to make sure they are also capable of
being run in full manual mode so that exposure, white-balance, f-stop, zoom,
etc. are at identical settings for both cameras. This means that you'll have to
take the time to manually adjust both cameras for each shot. By using an optical
method with one camera, as above, you wouldn't have to worry about that.
Matching zoom settings would be by far the most difficult thing to do.

I already have one of these for my Canon Rebel G film camera, from a
company called Loreo. They call this product a "3D Lens in a Cap." The
size of the frames of different cameras are different, so Loreo makes
beam splitters to fit the various types of cameras. It works OK, but
of course splits the frame in half, meaning that it has a narrow field
of view. Taking photos with it is like taking photos through a
keyhole. I would like to have two full frames. And, if I use 2 cameras
to do it, I might be able to adjust the lens separation, meaning that
I can make stereoscopic photos of larger objects.

On Aug 12, 4:48 pm, "dennis@home"
wrote:
"Roger N. Clark (change username to rnclark)" wrote in
...

There are (expensive) monitors with built in polarizers that
change polarization fast between two slides, and you wear
polarizing glasses that are synced to the display.
You see 3D quite well with the system.

Don't you mean they had goggles with an LCD shutter in them and the monitor
displayed alternating images which the shutter passed to the left or right
eye as required.
IIRC Imax do that now.

There is no need for both the projector and the goggles to have
alternating shutters. If the projector alternates the image on the
screen, a simple pair of polarized glasses (with the left and right
eyes rotated 90° to each other) is sufficient. The Imax polarized
goggles don't require any sort of external connection, and they are
fairly lightweight (though heavier than ordinary sunglasses).

On Aug 12, 10:12 am, Dave Cohen wrote:
Pooua wrote:
I have not found any stereoscopic cameras that meet my needs, so I
would like to assemble something that might. I want to rig two point-
and-shoot digital cameras together so they will record a stereoscopic
image. The problem is synchronizing the shutters. It should be
possible to use one camera for focusing, with the other camera set as
a slave. But, I don't know what circuitry would allow for this. Does
anyone have any suggestions?

Thank you.

I suspect the reason you can't find any stereoscopic cameras is the same
reason I have a bunch of 35mm slides that are never viewed, it's a pain
to have to use a special viewer but that's just my opinion so no
flaming. They used to make stereoscopic film cameras but they seem to
have gone out of fashion, again I suspect (but cannot prove) due to
viewing problems. Actually, you can train yourself to view two side by
side images in stereo without a viewer.
I doubt you'll have any luck jury rigging anything except a gizmo that
lets you slide the camera and take two shots. Fine for stills. They used
to sell an accessory that would put two images on film using a mirror
arrangement, but again I haven't seen anything like that recently.
Have you figured out how you would view or display the final result.
Dave Cohen

I have been using Pokescope software and hardware to view on my
computer and from prints of images that I made with a Loreo Lens-in-
Cap. This works OK, and has impressed several people in my office at
work. But, I would like something better than half a 35 mm frame. The
field of view from the lens-in-cap is so narrow that it is difficult
to get very much of the scene in the image. I don't know if that is
always going to be a limitation, or if widescreen scenics are
practical, but I would like a wider field of view.

[A complimentary Cc of this posting was sent to
Pooua
], who wrote in article . com:
There is no need for both the projector and the goggles to have
alternating shutters. If the projector alternates the image on the
screen, a simple pair of polarized glasses (with the left and right
eyes rotated 90=B0 to each other) is sufficient. The Imax polarized
goggles don't require any sort of external connection, and they are
fairly lightweight (though heavier than ordinary sunglasses).

A couple of years ago Metreon's IMAX switched from using
shutter-goggles to polarizing goggles. This is *enormous* decrease of
viewing quality.

Shutter goggles were giving practically infinite contrast ratio. The
polarizing goggles have a contrast ratio which looks like 10:1; so you
have very noticable ghosting. Each object is seen in triplicate: one
main image, and two ghosts to the left and to the right.

Hope this helps,
Ilya