Sam,

Did you have any trouble using shims or rings to get the 55's into the correct focus?

MF3D-group@yahoogroups.com wrote:

Medium Format Stereo Photography

Messages In This Digest (2 Messages)

1a.

Mamiya 55 - focus From: John Thurston

1b.

Re: Mamiya 55 - focus From: Sam Smith

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Messages

1a.

Mamiya 55 - focus

Posted by: "John Thurston" photo3d-list@thurstons.us   juneau99803

Thu Jun 21, 2007 2:20 pm (PST)

Sam, I've been thinking about your Mamiya 55
graft onto the TL120 but I'm wondering what
you're doing for focus?

As I recall, the C330 focused by moving the
entire lens board rather than rotating elements.
Have you incorporated any focus into your
TL120 or are you using your 55 equipped camera
as a fixed focus rig?
--
John Thurston
Juneau Alaska
http://stereo. thurstons. us

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Messages in this topic (2)

1b.

Re: Mamiya 55 - focus

Posted by: "Sam Smith" groups@stereoscopia.com   imn23dru

Thu Jun 21, 2007 6:12 pm (PST)

John,

It's focus free. Preset to 13 feet. At f22, my primary aperture,
everything is sharply in focus from 6 feet to infinity. Point and
shoot MF3D!

Sam

--- In MF3D-group@yahoogro ups.com, John Thurston wrote:
>
> Sam, I've been thinking about your Mamiya 55
> graft onto the TL120 but I'm wondering what
> you're doing for focus?
>
> As I recall, the C330 focused by moving the
> entire lens board rather than rotating elements.
> Have you incorporated any focus into your
> TL120 or are you using your 55 equipped camera
> as a fixed focus rig?
> --
> John Thurston
> Juneau Alaska
> http://stereo. thurstons. us
>

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Messages in this topic (2)

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Dr. Kevin Pernicano
Louisville, KY, USA (Home of the Kentucky Derby)

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Hi,

I've concluded that people tend to suffer from "cardboarding" more
than any other subject matter we can shoot in stereo.

I've read a lot of explanations for cardboarding, but here's a theory
I'm comfortable with regarding the cardboarding of people. I believe
it to be at least a contributing factor...

Humans almost never hold absolutely still. When one person looks at
another, even with their feet planted, they are both turning their
heads a little bit this way, a little bit that way, hips may rotate a
little, chins rise and fall, facial expressions flux during
conversation - the result is that bunches and bunches of z-axis
information describing the shapes of each person to the other is
accumulating with each passing second. Our senses are super-tuned
for data collection on the physical traits of people - for the
purpose of recognition - friend or foe, etc. Babies are born with
this ability. Comparatively, I suspect we're not nearly as good at
accumulating this data with non-human objects. Even the range of
our stereo vision is exaggerated with human subjects. We can
recognize people a long way off - as long as there's some movement,
especially rotation.

When we look at a static stereo image that includes a human subject
amidst other objects, not only is the human we're looking at holding
impossibly still, we're not moving either! A simple tilt of your
head is all it takes to double or triple your stereo base in real
life, but with a stereo viewer, your perspective is frozen - you
can't move, they aren't moving, and thus you are deprived of your
ability to accumulate the data that normally enhances our perception
of another human's form. So... they look flat - like cardboard cutouts.

I'm shooting from the hip here, so feel free to comment, for or against.

Now fasten your seat belt and consider this: Could it be that the
way people look in an ortho stereo view is much more accurate than
the way they look in real life? In real life, we are making everyone
look more bulbous, giving them more z-axis depth than they actually
have in our involuntary quest to catalog them for future
recognition. Perhaps, people really aren't as bulbous as we perceive
them to be. We could be hypering them to see and record a
caricature of reality.

A couple of years ago, I was flipping channels and saw a hot rod show
where they were talking about all the modifications made to a
t-bucket roadster. It had a big supercharger scoop over a motor that
had nearly everything chrome plated, with red and blue annodized
steel braided wiring and hoses, etc. It was beautiful. The thing
that caught my attention though was that when they first walked up to
the car, the cameraman just held the camera fixed, with a wide view
of the whole car as these two guys first stood in front of it talking
about the car, then started walking around it. When they started
talking about the motor though, the cameraman went into a mode I
have never seen before - he came in real close to the motor, so that
the field of view was no more than about one foot square and started
moving very fluidly and without pausing, slowly all over the entire
engine, swooping down and around and behind and overhead and all
around every component. He'd rotate around the starter, then rotate
around the supercharger, then rotate around the distributor, etc...
all the while moving, never stopping. It was WONDERFUL because it
allowed you to accumulate 3D information about the motor and the
relationship of all the parts to each other across a time component -
so it was like 4D with the z-axis missing to give a very effective
"2D + Time" 3D image! Brilliant camera work. Me like!

Mike Davis

I agree that people should not be stiffly posed because the outcome is that
when not engaged in some activity, they appear like
living statues in stereoviews, but definately not flat. I think
cardboarding, which provides a flat layered effect is more the result
of longer focal length lenses which tend to flatten images.

OTOH 50s-style 35mm stereo cameras were equipped with moderate wideangle
lenses, mainly to preserve depth of field and
to simulate the angle of view as seen by humans. WA lenses tend to make for
roundness of subjects and thus are rarely used for
portraits in mono photography. I suspect that if medium-format stereo rigs
were equipped with equivalent WA lenses, there
would be little or no cardboarding as a result.

Marshall

----- Original Message -----
From: "Michael K. Davis" <zilch0@primenet.com>
To: <MF3D-group@yahoogroups.com>
Sent: Monday, June 25, 2007 12:14 AM
Subject: [MF3D-group] Cardboard people


> Hi,
>
> I've concluded that people tend to suffer from "cardboarding" more
> than any other subject matter we can shoot in stereo.
>
> I've read a lot of explanations for cardboarding, but here's a theory
> I'm comfortable with regarding the cardboarding of people. I believe
> it to be at least a contributing factor...
>
> Humans almost never hold absolutely still. When one person looks at
> another, even with their feet planted, they are both turning their
> heads a little bit this way, a little bit that way, hips may rotate a
> little, chins rise and fall, facial expressions flux during
> conversation - the result is that bunches and bunches of z-axis
> information describing the shapes of each person to the other is
> accumulating with each passing second. Our senses are super-tuned
> for data collection on the physical traits of people - for the
> purpose of recognition - friend or foe, etc. Babies are born with
> this ability. Comparatively, I suspect we're not nearly as good at
> accumulating this data with non-human objects. Even the range of
> our stereo vision is exaggerated with human subjects. We can
> recognize people a long way off - as long as there's some movement,
> especially rotation.
>
> When we look at a static stereo image that includes a human subject
> amidst other objects, not only is the human we're looking at holding
> impossibly still, we're not moving either! A simple tilt of your
> head is all it takes to double or triple your stereo base in real
> life, but with a stereo viewer, your perspective is frozen - you
> can't move, they aren't moving, and thus you are deprived of your
> ability to accumulate the data that normally enhances our perception
> of another human's form. So... they look flat - like cardboard cutouts.
>
> I'm shooting from the hip here, so feel free to comment, for or against.
>
> Now fasten your seat belt and consider this: Could it be that the
> way people look in an ortho stereo view is much more accurate than
> the way they look in real life? In real life, we are making everyone
> look more bulbous, giving them more z-axis depth than they actually
> have in our involuntary quest to catalog them for future
> recognition. Perhaps, people really aren't as bulbous as we perceive
> them to be. We could be hypering them to see and record a
> caricature of reality.
>
> A couple of years ago, I was flipping channels and saw a hot rod show
> where they were talking about all the modifications made to a
> t-bucket roadster. It had a big supercharger scoop over a motor that
> had nearly everything chrome plated, with red and blue annodized
> steel braided wiring and hoses, etc. It was beautiful. The thing
> that caught my attention though was that when they first walked up to
> the car, the cameraman just held the camera fixed, with a wide view
> of the whole car as these two guys first stood in front of it talking
> about the car, then started walking around it. When they started
> talking about the motor though, the cameraman went into a mode I
> have never seen before - he came in real close to the motor, so that
> the field of view was no more than about one foot square and started
> moving very fluidly and without pausing, slowly all over the entire
> engine, swooping down and around and behind and overhead and all
> around every component. He'd rotate around the starter, then rotate
> around the supercharger, then rotate around the distributor, etc...
> all the while moving, never stopping. It was WONDERFUL because it
> allowed you to accumulate 3D information about the motor and the
> relationship of all the parts to each other across a time component -
> so it was like 4D with the z-axis missing to give a very effective
> "2D + Time" 3D image! Brilliant camera work. Me like!
>
> Mike Davis
>
>
>
>
> Yahoo! Groups Links
>
>
>
>
> __________ NOD32 2351 (20070625) Information __________
>
> This message was checked by NOD32 antivirus system.
> http://www.eset.com
>
>

> OTOH 50s-style 35mm stereo cameras were equipped with moderate wideangle
> lenses, mainly to preserve depth of field and
> to simulate the angle of view as seen by humans.

????

1. For the size of the Stereo Realist format, a 35mm lens is rather normal
and not "moderate wideangle".

2. Where did you read that the choice of 35mm lens was done to "preserve
depth of field"?

3. What does "simulate the angle of view as seen by humans" mean? To
compare the angle of view as seen in real life vs. as seen through a viewer,
you have to compare the FL of the taking vs. the viewing lens. The absolute
value of the taking lens FL is irrelevant.

George T.

> I've concluded that people tend to suffer from "cardboarding" more
> than any other subject matter we can shoot in stereo.

Compared to what? Trees? Houses? Animals? Mountains? Cars?

The ratio of thickness/height for humans is one of the smallest, compared to
other subjects, even animals (because they do not stand up in two legs). I
think that's a factor too.

George T.

Kevin,

I cast, tapped and machined barrels to fit. Sorry, no quick fix here,
especially for the accuracy needed.

Sam

--- In MF3D-group@yahoogroups.com, "Dr. Kevin Pernicano"
wrote:

>
> Sam,
>
> Did you have any trouble using shims or rings to get the 55's into

the correct focus?

>

> The ratio of thickness/height for humans is one of the smallest, compared to
> other subjects, even animals (because they do not stand up in two legs). I
> think that's a factor too.
>
> George T.

just had a closer look and print out of my images from my Canon 5D and the
Loreo stereo lens attachment. Much cardboarding.

Lenses are closer together than Sputnik or the Realist.

Wonder if this is the cause?

M