[Konvas] Film thickness? (off-topic)

[Rick Garbutt]

Oh, Adam!

No!  NONONONO!

        > Hey all,
        > This is off-topic, but how do you find out the thickness of a
        >particular  film? I bought an Operators Manual for a FASTAX 16mm
       >camera that came  with a (supposedly) working WF3 Fastax (all I had
        >to do was pay for the  extra $20 for the camera shipping).
> 
        > It says inside the door:
> 
        > CAUTION
        > to avoid damaging camera
> 
        > USE only fresh
        > full pitch (.3000")'

This is NOT the thickness of the film!  The "pitch" is the distance between
correlative points on any two consecutive frames, say, leading perf edge to
leading perf edge.  Or tailing perf edge to tailing perf edge.

In this case, the camera, specifically the sprocket teeth, are designed to
properly slot into film stock with "3000-pitch" perforations.  Meaning
0.3000 inches between them correlative points.

3000-pitch film is USUALLY print stock, as opposed to 2994-pitch (0.2994
inches between correlative points) camera stock.  As print stock is commonly
around ISO 5, it's quite unsuitable for highspeed work, unless you have
convenient access to nuclear weapons.  You have to special order camera ISO
stocks with 3000- (also called "long-pitch") stock.

On 16mm camera stock can labels, you'll see this encoded as 2R-2994 (2 rows
of 0.2994" pitch perforations).  On print stock cans, probably 1R-3000 (1
row of 0.3000" pitch perfs).

Remember print stock has 1 row of perfs because of that optical sound track
that will probably end up there; Super16 camera stock will have 1R-2994
perfs because it will use that extra area for its larger image.

At the risk of being pedantic, the why of it has to do with how continuous
contact printers work.  As they guide the original and print stocks together
in the gate, both films come onto a common sprocket as they prepare to go
past the exposure aperture.  Traditionally (with one weird exception I can
think of in the Uhler Cine Printer, NOT a professional machine!) the
original lies at the bottom of the sprocket teeth; the print stock above it.

If you think about it in profile, both films are passing along an arc of a
circle, defined by the circumference of the main printer sprocket.  And the
print stock's circle is bigger BY THE THICKNESS OF THE ORIGINAL CAMERA
STOCK.  In practical terms, this means that each print frame is kindasorta
"taller" by 0.0006 inches.  Not cumulative.

What this means, in terms of your camera, is that the perfs are likely to be
deformed as they slide down to the bottom of the sprocket teeth.  You MAY
get away with this at lower speeds, but at higher speeds, all sorts of new
rules set in with a vengeance, and you may, indeed, damage the camera.

Peer inside, and you'll find (I'll bet) your sprockets NEED 2R-3000 film.
This is because, especially as you go to higher speeds) the camera MUST pull
the film symmetrically through, or it will tend to twist or torque in the
gate, rendering the insides of the camera into what We In The Sciences call
"schrapnel".  And I'm not kidding!  Some of the forces inside the very
camera you have can render it an extremely dangerous thing to fiddle with.
So don't go defeating safety interlocks, and UNPLUG THE DAMN THING BEFORE
you ever open the door with the intent of sticking personal appendages in!
Seriously.  Unless you and the tips of your fingers have an iffy
relationship you might like .... er .... severed.

The "factory fresh" note is a kind of disclaimer:  film stock MAY shrink,
and MAYBE unevenly, as it ages.  Leading to even more fun with them
highspeed sprocket teeth.  Think of them as your very own tiny table saw,
working in total darkness.  Scary, innit?

> 
        > WOLLENSAK FASTAX FILM

...which was probably repackaged Kodak, thugh Wollensak/Fastax was a
division of 3M, which did make various films, so the Kodak thing isn't a
guarantee.

        > DO NOT let door
        > when removed from camera
        > rest on viewing prism

If you pop the door off its hinge pins (often makes threading easier) be
sure to set it on the viewvinder side.  If you set it on the prism, there's
a good likelihood the prism may become misaligned, hence pointless.  Or you
may damage it.

Alternatively, you could make a little door-holding jig that would stop the
prism from whacking into your table.  A couple of pieces of 2 x 2 lumber and
a piece of scrap plywood will do nicely.

Another caveat here:  you get to thread the camera wrong exactly ONCE.  Any
sort of highspeed film jam is likely fatal.  Even once.

> Looking in the Operators Manual (which has a lot of information, btw,
> and not just related to the WF3 model), all the models that they made at
> the time are listed. It says the following for the WF3:
> 
> Catalog No.: WF3
> Frame size : 16mm FF (full frame)
> Film capacity: 100'
> Min. Speed PPS: 150
> Max. Speed PPS: 8000
> Camera Type: Framing

As opposed to STREAK cameras, which do not have the rotating prism.  I've
seen some of these sold very cheap on eBay, and if anyone thought they were
going to get a "normal" image out of them, they were surely disappointed!

> Lens Mount: FX1

And if you have a good pet machinist, you CAN change this to a Nikon or
Canon mount.  My WF-7 is Nikon-ized.  Can send a photo off-list if anyone's
fascinated.

You CANNOT modify the full-frame (WF-8) 35mm Fastax to Nikon mount, because
the optical and physical thickness of the rotating prism is too great.  If
you were just to be pig-headed and bolt one on, it'd effectively have a
sizeable extension tube on it, and you would only be able to focus on real
macro subjects, and you would never get infinity focus.  For the full-frame,
you need to either leave the original Fastax mount on, or convert to
Hasselblad or Bronica mounts.

> Std Lens: 2" f/2.0
> Te*: 1 / 3 x PPS
> (someone has written above it: 1 / 3 x 4000 = 1 / 12,000 sec)
> Size and Weight: 12" x 12" x 12"  25lbs.
> Shipping Size and Weight: 17" x 16" x 16"  50lbs.
> Voltage Requirements:
> WF01 Goose AC Volts: 30 Min / 280 Max
> WF300A DC Volts: 11 Min / 28 Max
> 
> The mathematical formula Te* (actually, the "e" is extremely small, but
> I am typing in ASCII) looks to mean the effective shutter speeds. I
> believe PPS means "Pictures Per Second". Btw, there are a good many
> other cameras, with their information, listed.

PPS = Pictures per Second, indeed.

T<sub>e = 1/3 x PPS does give you effective exposure time.  Why 1/3 and not
1/2?  Well, for starters, the spinning prism costs you at least 1/2 stop due
to absorption; as you creep up past about 200 PPS, you start getting
reciprocity failure effects setting in, and you have to de-rate the stock.
And what's one of Rick's favorite mantras?  <all together, now>  SHOOT SOME
DAMN TESTS BEFORE YOU SHOOT PRODUCTION FOOTAGE.

1/3 x 4000 = 1/12,000 must have been for the arithmetically and/or
memory-challenged.

If I'm using my regular light meters (instead of the gen-yoo-wine Wollensak
Fastax meter I do own, which factors in reciprocity failure and absorption)
I derate the stock at least 1 1/2 stops to keep the exposure in the
ballpark.  As a starting point.
 
> On another page, it lists the camera as a "Category I" and shows the AC
> and DC speed curves. DC is listed from 8 Volts (2.3 Amps) to 28 Volts
> (3.0 Amps). It shows a graph with "Applied Voltage", which is higher,
> and "Operating Voltage", which is lower - so an 11V applied voltage is
> an 8V operating voltage.

DC is used for the lower camera speeds, as there's better torque with DC
than AC at low speeds, and the camera won't tend to stall out and just sit
there, humming with an offended tone.  (If you look at the thing, you'll see
the camera body and takeup spindle are both driven by big, dumb, clunky ol'
brush motors, which, seriously, would do just fine running a vacuum cleaner.
They're rated at about 1/3 to 1/2 hoursepower.  Your homework assignment is
to calculate what that is in watts.)  I'd suggest getting that MPJA
(www.mpja.com) DC speed controller, which will more stably control the
camera at low speeds, and allow you to use it considerably below 150 PPS.
And the kit is 14 lousy bucks + shipping, last time I looked.  Alas, the
MPJA controller doesn't come with the niceties of the official Wollensak
GOOSE controller, which allows controllable millisecond delays between the
event firing a sensor and the camera automatically taking off.  MANY slow
motion events happen far, FAR too fast for a human trigger to reliably start
the camera.  If you can coordinate a 7,000 fps camera to get a bullet
leaving the muzzle of a gun barrel, I want to take you to Vegas.

> Actually, for as boring as it may look, it is absolutely fascinating
> stuff. The schematics, curves, and everything else are in there, so if
> the camera does work (and I can find film with a thickness of .2992 to
> .3000), then I can start doing really cool things like film hummingbirds
> and bees, work with miniatures, and other cool stuff...

There's a grimly funny story about the bees.  If you look at the 1940s-ish
SMPTE articles about studying bee flight (to resolve the "according to the
laws of aerodynamics, the bumble cannot fly.  The bumblebee, not having
studied the laws of aerodynamics, flies anyway" arument) involved GLUING the
poor creatures to supports (well, panning a 50-pound highspeed non-reflex
camera to follow a zippy insect a half-inch long is kind of way beyond Zen
for an Operator!) for filming.  Camera stocks were low enough speed such
that HUGE, focused lights were needed, so the sequence of events went
something like this:

    1.  Glue bee to post.  Trust us:  bee WILL be flapping its wings.
    2.  Strike huge arc lamp.
    3.  IMMEDIATELY Fire camera.
    4.  Kill huge arc lamp.  About 4 seconds will have elapsed since Step 1.
    5.  Wet index and middle fingers to extinguish smoking bee carcass.
    6.  Process film.

I doubt PETA would comment favorably on that technique today.  And, yes, I
know what the "according to the laws of aerodynamics...." resolution is, and
you're going to have to beg for it.  And, no, I was never a party to
incinerating bees in the name of furthering aeronautic science.  Or anything
else, for that matter.

I envy you the manual, for in the process of acquiring the 5 Fastax and 1
PhotoSonic rotating prism cameras I have, I haven't managed to score one.
The subject is truly fascinating, but be warned it's very deep end of the
pool.  If I can bribe you for a photocopy, please drop me a note off-list.
TA!
 
> But, if it doesn't work, I can always use it as a really heavy
> paperweight for when another hurricane blows through...
> 
> Whoops, I just realized I was digressing big-time. Back to my question:
> how do you find out the thickness of film?

Even though you don't need it for your project (see diatribe above) you can
find out this, and all SORTS of other exotic film info (includibng what
"pitch" is all about for 16mm and 35mm films, including diagrams) in Kodak
Publication #H-1, which I'm still convinced should be required reading for
anyone presuming to pick up a camera.  And there should be a TEST.

Very best to all,
Rick (just back from his 2nd Burning Man!) Garbutt, soc