The Royle Family turned into a £100,000 farce due to a mystery camera fault.

"Roderick Stewart" wrote in
message
There is a maximum percentage of the available time for which a frame of
film
*can* be exposed, because the shutter needs to be closed long enough for
the
film to be physically moved. I understand that it is typically 50%, so
film
being shot at 25fps will only be exposed for 1/50 second, and will only
see
half the action. I don't think it's possible for a normal film camera with
a
shutter to have a duty cycle of greater than about 75%.

Years ago I remember seeing a design for a cine camera which was ingeneous
but seemed rather unworkable. It was designed to avoid the problem of only
being able to expose the film for a proportion of the duty cycle, so as to
give better representation of movement and to allow slow film stock to be
used in dimmer conditions.

It used two rolls of film, two shutters and two lenses. One lens/shutter
exposed a frame for the complete 1/24 or 1/25 second, then while the other
lens/shutter exposed a frame on its film, the first film was advanced *two*
frames.

You ended up with two films, each with alternate exposed and unexposed films
which could be interleaved when the negative was printed to positive. It was
wasteful of film (!) and could only be used for negative film where the
unexposed frame was transparent, allowing the exposed frame of the other
film to be seen through it.

A real Heath-Robinson arrangement!!!!


What was the duty cycle of telerecording cameras which filmed a TV screen? I
think they managed to reduce the pull-down time, at the expense of a *very*
noisy mechanism that had a tendency to knacker the sprockets of the film.

Given that telecine equipment often used a rotating prism to allow the film
to be run continuously rather than intemittently, could the same mechanism
have been used in the camera to allow continuous movement of the film?

In article , Zathras
writes
On Wed, 16 Dec 2009 13:08:12 GMT, SpamTrapSeeSig
wrote:

In article , Zathras
writes
I would suggest that both those deficiencies could be overcome by
careful mic work.

Then you are an ideal person for the new media revolution.

LOL..I'm a battered old Broadcast Engineer who, a long time ago, gave
up (professionally) arguing against stupid budgets, cheap setups and
amateurism in broadcasting. We were told by a *very* senior business
manager that if cost cuts caused programmes to fall off air then so be
it. Once that holy grail is bazooka'd then what's the point in
debating (professionally) the merits of quality vs penny pinching in
other areas?

So, if Production want to shoot an improved version of Avatar with
only a DV Camcorder, Mini Maglite and a Tesco laptop, then, as long as
it doesn't impact on my salary - good for them, I say!

My resigned acceptance of the new media revolution shouldn't be
mistaken for me not being the first person to help all those poor
souls onto the "B Ark"..if only..

Points well taken :-)
--
SimonM
----- TubeWiz.com -----
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Try it today! (now with DFace blurring)

In article , Martin wrote:
Given that telecine equipment often used a rotating prism to allow the film
to be run continuously rather than intemittently, could the same mechanism
have been used in the camera to allow continuous movement of the film?

I think this is what they use in Imax cameras, where the film is so big it
would be ripped to shreds by any attempt to advance it intermittently at the
usual speed. It's certainly what they use in the projectors so presumably the
cameras also. Perhaps the extreme precision required is why it isn't done with
the smaller guages.

Rod.
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Virtual Access V6.3 free usenet/email software from
http://sourceforge.net/projects/virtual-access/

On Thu, 17 Dec 2009 05:47:34 -0000, Roderick Stewart
wrote:

Roderick,

Given that telecine equipment often used a rotating prism to allow the film
to be run continuously rather than intemittently, could the same mechanism
have been used in the camera to allow continuous movement of the film?

I think this is what they use in Imax cameras, where the film is so big it
would be ripped to shreds by any attempt to advance it intermittently at the
usual speed. It's certainly what they use in the projectors so presumably the
cameras also. Perhaps the extreme precision required is why it isn't done with
the smaller guages.

No, they use a double claw movement - see this web page.

http://www.in70mm.com/newsletter/199...bsen/index.htm

There would be a reluctance to put a prism in the light path of a film
camera due to the optical problems that would ensue.

Jim.

Dave Plowman (News) wrote:

Good greif. It's snowing...

http://www.thedailymash.co.uk/news/society/london-sacrifices-virgins-after-centimetre-of-snow-200912162316/


--
Mark
Please replace invalid and invalid with gmx and net to reply.

www.paras.org.uk

"Jim Guthrie" wrote in message
...
On Thu, 17 Dec 2009 05:47:34 -0000, Roderick Stewart
wrote:

Roderick,

Given that telecine equipment often used a rotating prism to allow the
film
to be run continuously rather than intemittently, could the same
mechanism
have been used in the camera to allow continuous movement of the film?

I think this is what they use in Imax cameras, where the film is so big it
would be ripped to shreds by any attempt to advance it intermittently at
the
usual speed. It's certainly what they use in the projectors so presumably
the
cameras also. Perhaps the extreme precision required is why it isn't done
with
the smaller guages.

No, they use a double claw movement - see this web page.

http://www.in70mm.com/newsletter/199...bsen/index.htm

There would be a reluctance to put a prism in the light path of a film
camera due to the optical problems that would ensue.

Why would there be more of an optical problem with a camera than a
projector/telecine?

On Thu, 17 Dec 2009 08:20:12 -0000, "Martin" wrote:

There would be a reluctance to put a prism in the light path of a film
camera due to the optical problems that would ensue.

Why would there be more of an optical problem with a camera than a
projector/telecine?

Apart from any glass quality problems, the major consideration might
be how you would fit it in if you wanted to keep the camera body of a
reasonable size.

Another problem might be registration. In a register pin camera the
film is locked in position when the shutter is open giving a steady
image. Granted 16mm cameras like Aaton don't have a register pin, but
they have a sophisticated claw mechanism which allows a steady frame
during exposure. A rotating prism would have to be synchronised very
accurately to the moving film to ensure that the frame pitch was
exactly correct and that might be difficult to achieve in a piece of
portable equipment running under a wide variety of conditions. And
the camera is the originating piece of equipment and its steadiness
should be as near perfect as is possible to get.

I've also just done a check and as far as I can see, a rotating prism
was used in the Rank Mk1 telecine many moons ago. Other methods of
transferring film to video used different methods of transferring the
image from the MkII onwards. Rotating prisms have been used on film
editing equipment for years - like Steenbeck flatbed machines - but
the quality and steadiness was good enough for editing.

Jim.

In article , Ivan
wrote:


"Jim Lesurf" wrote in message
...
In article en.co.uk,



Or maybe this was a deliberate attempt to make the result have the
same visible defects of 24/25 frame/sec film can exhibit. I can only
speculate on why it was allowed to happen in any particular case.


From what I've read in the past on various newsgroups involving people
in the broadcasting industry, discussing the 'dropping of frames' and
various other 'filmic effects', I think that your speculation would be
the most likely reason.

I confess I would not be astonished if that were the case. :-)

I can understand why some content might be felt to be 'art' and benefit
from reminding the viewers that they were seeing a 'film'.

But it baffles me that they do it with a documentary about the natural
world. Perhaps it is another sign that the people actually making the
programme have no real interest themselves in the content, so instead want
to make a 'feature' of various visual effects. That seems particularly
common with 'science' documentaries in recent years. Can sometimes be so
distracting that the content becomes inaccessible.

Slainte,

Jim

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On Wed, 16 Dec 2009 10:32:10 +0000, Zathras
wrote:

The most obvious things missing from those are 'only' pertinent to sound.
Like decent acoustics and sound proofing. Even more important in these
days of the whispering actor.

Being partially deaf, I hate those. Worst one at the moment is the
scientist in Paradox, who whispers with a Scottish brogue and hardly
moves his lips!

I would suggest that both those deficiencies could be overcome by
careful mic work. Even the cheapest shows, I'm aware of, go through a
pretty full-on sound dubbing process where 'acoustics' and other
missing effects can be added. Nevertheless, I'm aware of one Soap that
added sound proofing matting to their hangar walls.

Matting, while having a deadening effect, would not stop sound. No
substitute for thick heavy walls.
--
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It's only Usenet, no one dies.
My opinions, not the committee's, mine.
Simple RFDs www.ckdog.co.uk/rfdmaker

In article ,
Geoff Berrow wrote:
The most obvious things missing from those are 'only' pertinent to
sound. Like decent acoustics and sound proofing. Even more important
in these days of the whispering actor.

Being partially deaf, I hate those. Worst one at the moment is the
scientist in Paradox, who whispers with a Scottish brogue and hardly
moves his lips!

You want to try recording them ;-(

--
*Constipated People Don't Give A Crap*

Dave Plowman London SW
To e-mail, change noise into sound.