crazy OOF shape

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Paul Furman - 27 Oct 2005 18:15 GMT

This is a screen shot from a movie showing some really wacky gear shaped
bokeh out-of-focus circles:
<http://www.edgehill.net/1/?SC=go.php&DIR=Misc/misc-photos/temp&PG=1&PIC=2>

Also, she used this Hasselblad digital camera:
<http://www.edgehill.net/1/?SC=go.php&DIR=Misc/misc-photos/temp&PG=2&PIC=7>
<http://www.edgehill.net/1/?SC=go.php&DIR=Misc/misc-photos/temp&PG=1&PIC=5>
Is there really such a thing with a top LCD screen? They showed the LCD
with live preview but I assume that was just for effect in the movie and
it works like a DSLR.

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Matt Clara - 27 Oct 2005 18:45 GMT

> This is a screen shot from a movie showing some really wacky gear shaped
> bokeh out-of-focus circles:

<http://www.edgehill.net/1/?SC=go.php&DIR=Misc/misc-photos/temp&PG=1&PIC=2>

> Also, she used this Hasselblad digital camera:

<http://www.edgehill.net/1/?SC=go.php&DIR=Misc/misc-photos/temp&PG=2&PIC=7>

<http://www.edgehill.net/1/?SC=go.php&DIR=Misc/misc-photos/temp&PG=1&PIC=5>

> Is there really such a thing with a top LCD screen? They showed the LCD
> with live preview but I assume that was just for effect in the movie and
> it works like a DSLR.

Are you sure it's digital, and not just a look at the focus screen?

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Paul Furman - 27 Oct 2005 19:10 GMT

>>This is a screen shot from a movie...
>
[quoted text clipped - 8 lines]
>
> Are you sure it's digital, and not just a look at the focus screen?

Is that how those things work, you just look down at a three-inch
viewfinder from a foot away? It is medium format right? I've never seen
one in action. I thought it was portrayed like a P&S live preview LCD
where you could see the action moving on the screen.

She also used a large format camera & the viewfinder for that is shown
as this enormous 1-foot refractor magnifier thing that you look at from
a foot away:
<http://www.edgehill.net/1/?SC=go.php&DIR=Misc/misc-photos/temp&PG=1&PIC=1>

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Matt Clara - 27 Oct 2005 19:16 GMT

> >>This is a screen shot from a movie...
> >
> >>...she used this Hasselblad digital camera:

<http://www.edgehill.net/1/?SC=go.php&DIR=Misc/misc-photos/temp&PG=2&PIC=7>

<http://www.edgehill.net/1/?SC=go.php&DIR=Misc/misc-photos/temp&PG=1&PIC=5>

> >>Is there really such a thing with a top LCD screen? They showed the LCD
> >>with live preview but I assume that was just for effect in the movie and
[quoted text clipped - 6 lines]
> one in action. I thought it was portrayed like a P&S live preview LCD
> where you could see the action moving on the screen.

The photo you offer shows a focus screen looking brighter and clearer than
it typically would from a foot away, but they would have enhanced it for the
movie, otherwise the audience wouldn't make anything out of it. And yup,
that's how they (waist level viewfinders) work.

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Regards,
Matt Clara
www.mattclara.com

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Rob Novak - 28 Oct 2005 14:59 GMT

>The photo you offer shows a focus screen looking brighter and clearer than
>it typically would from a foot away, but they would have enhanced it for the
>movie, otherwise the audience wouldn't make anything out of it. And yup,
>that's how they (waist level viewfinders) work.

Yep.

And the device on the back of the view camera is a Fresnel lens, used
to magnify the image on the groundglass for fine focusing.

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Joe Makowiec - 28 Oct 2005 00:45 GMT

> This is a screen shot from a movie showing some really wacky gear
> shaped bokeh out-of-focus circles:

Which movie?

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Paul Furman - 28 Oct 2005 01:00 GMT

>>This is a screen shot from a movie showing some really wacky gear
>>shaped bokeh out-of-focus circles:
>
> Which movie?

"What the Bleep do we Know?" The main character is a photographer
struggling with emotional problems. She's also deaf not that it matters
much. Then the story alternates with interviews of intellectuals
discussing religion & quantum physics as her solutions to life's
problems unfold. People either love it or hate it, probably.

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Joe Makowiec - 28 Oct 2005 01:47 GMT

> "What the Bleep do we Know?"

Out of theaters, at least near me. I guess I'll have to find it on disc.

> The main character is a photographer struggling with emotional
> problems. She's also deaf not that it matters much.

Marlee Matlin - I thought she looked familiar. I guess that makes sense.

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bjw@mambo.ucolick.org - 29 Oct 2005 00:11 GMT

> This is a screen shot from a movie showing some really wacky gear shaped
> bokeh out-of-focus circles:
> <http://www.edgehill.net/1/?SC=go.php&DIR=Misc/misc-photos/temp&PG=1&PIC=2>

That's what an iris diaphragm looks like when the leaves get
slightly offset from where they are supposed to be. The "notch"
in the gear is the end/corner of the leaf, which normally
should be overlapped by the next leaf over.

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Paul Furman - 29 Oct 2005 07:12 GMT

>>This is a screen shot from a movie showing some really wacky gear shaped
>>bokeh out-of-focus circles:
[quoted text clipped - 4 lines]
> in the gear is the end/corner of the leaf, which normally
> should be overlapped by the next leaf over.

So it's a broken lens, like they tried to stop it up wider than the lens
was designed for. Those are really huge OOF circles too. I might guess
the faster the lens, the larger the OOF circles?

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bjw@mambo.ucolick.org - 29 Oct 2005 08:33 GMT

> > That's what an iris diaphragm looks like when the leaves get
> > slightly offset from where they are supposed to be. The "notch"
[quoted text clipped - 4 lines]
> was designed for. Those are really huge OOF circles too. I might guess
> the faster the lens, the larger the OOF circles?

It's not really broken, but the diaphragm is a little out of
adjustment. That's more common than you might think. I'm a
little surprised to see it in a movie, but perhaps not if it
was a low budget production (that is, a high budget production
would probably use high dollar rented equipment that was more
throughly checked out). It's most likely to show up about one
stop down from wide open. Wide open you don't see the iris leaves.

The out of focus circles (circles of confusion) are proportional
to the physical diameter of the aperture (e.g. 25mm for a 100mm
lens at f/4), when distances of subject and background are fixed.
This is probably in the Lens FAQ if that's still around. A long
and fast lens produces more blur in the background, this is a
well known effect.

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no_name - 31 Oct 2005 18:32 GMT

>>>That's what an iris diaphragm looks like when the leaves get
>>>slightly offset from where they are supposed to be. The "notch"
[quoted text clipped - 8 lines]
> adjustment. That's more common than you might think. I'm a
> little surprised to see it in a movie,

Keep in mind that projected on the screen you probably wouldn't see
those hi-lites in quite the same way you see them in the still image,
since they would be on the screen for only 1/24 of a second before moving.

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Alan Browne - 29 Oct 2005 14:53 GMT

> This is a screen shot from a movie showing some really wacky gear shaped
> bokeh out-of-focus circles:
[quoted text clipped - 6 lines]
> with live preview but I assume that was just for effect in the movie and
> it works like a DSLR.

No. The Hasselblad DSLR's (or backs available for the Hassy's) are
rectangular format, not square; and the display is on the back not the
top. The camera looks like a 500 series Hassy. If it was presented as
"digital" than it was simply the filmmaker's way of illustrating the
story.

On the last link above, you can even see that the back is an A12 film back.

Cheers,
Alan.

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