John Beale
March 20 1999
USAGE EXAMPLES - Hints for better video
Exposure issues.
I have used the TRV900 mostly for filming dance performances.
When I'm filming a performance on stage, I notice a large part of the
frame is filled by the flat black stage surface, and background areas in
deep shadow (outside the spotlights). This confuses the camera's
auto-exposure circuit, which boosts the gain so much the blacks are gray,
the performers are overexposed, and the whole image is grainy. One option
is to simply use manual exposure control (I find the "zebra bars"
indicating overexposed areas handy). Remember when you change exposure
settings the picture will jump to the new level; avoid changing settings
while rolling if possible. If want to leave the camera in automatic
exposure mode, go to the menu function labeled "AE SHIFT" and adjust the
setting down a few notches until the picture looks right (if you can-
unfortunately the entire range of AE SHIFT seems only about +/-1
f-stop). If you can AE SHIFT enough, your exposure will have a good chance
of being correct even as the overall lighting level moves up or down.
In contrast to the above situation, I filmed a dance performance
outdoors in the afternoon on a sunny day. Normal settings worked well for
the dancers, but the announcer stood in the shade, and behind him was the
white wall of a house in full sun. The camera closed the aperture to expose
the house properly, putting the announcer's face into dark shadow. A touch
of the "backlight" button (top, near the lens) corrected the exposure of
this scene quite well. Just remember to take the backlight mode off again
when you turn back to the normally-lit scene!
Autoexposure vs. Manual.
For many scenes, I found the camera's automatic exposure system worked
as well or better than what I could adjust manually. However, for the two
unusual cases of very dark and very bright backgrounds, I needed to shift
the exposure myself. The key to getting the best video is to recognize
which situations call for correction... and which don't. It takes
a bit of practice to understand how the image on the LCD viewfinder or
viewscreen will compare to a CRT (TV) image.
I find that LCD displays have a different apparent contrast range than CRT
monitors. This is especially true of the fold-out LCD screen, which of
course has a different contrast level depending on the exact angle from
which you view the display, as well as the brightness setting. The
viewfinder may be more reliable since you view it from a fixed angle, but I
think that for the most accurate brightness/contrast judgement you need an
external CRT display.
If you're trying to capture a one-time only event, don't have an external
monitor, and aren't very comfortable with LCD-CRT differences, consider
that automatic exposure is more likely to give you something roughly right,
as opposed to manual control which can be drastically wrong. This advice
goes for any camera with an LCD viewfinder, by the way.
If you are using manual control, a few hints: video of people is
normally exposed for the most natural skin tones on the face. This is
important due to dynamic range (the range of brightness values which can be
recorded in a single frame). Video cameras in general have very limited
dynamic range (about 6 f-stops, compared to about 11 stops for film) so you
may have to let a very white shirt saturate to white, or a very dark jacket
fall to black. Just remember that the area covered by the "zebra stripes"
will be plain white on the screen, and show no detail at all. Video with a
large region of saturated white usually looks bad (the reason interview
subjects should be convinced not to wear a plain white
shirt). Unless you're filming a skier on a bright white, snowy mountain,
you want to keep the zebra-striped areas fairly small. On the other hand,
remember the limited dynamic range... if there are no zebra-striped dots at
all in-frame, you may be close to a too-dark image.
To repeat myself, I've found it hard to beat the
camera's auto-exposure system for "normal" shooting conditions.
Using a Grey Card.
Camera auto-exposure circuits are designed assuming every scene has 18%
reflectance. This is often approximately right, but if you want to do a
professional job you'll set the exposure based on a known fixed reference
(grey card), which gives you a consistently correct setting regardless of
the actual tones in your scene (assuming they aren't SO bright or dark as
to exceed the dynamic range of the camera). Even the casual user may need
to use this method occasionally if there is unusual subject matter, eg. a
small skier on a mountain of bright white snow.
It wasn't obvious to me at first how to use a standard 18% grey card with
the camera. This requires that you let the camera set the exposure based on
the grey card, but then "lock" that setting while you compose the real
scene. It isn't a single button-press, you need the following procedure:
First, set the exposure control switch on the side near the rear of the
camera (labelled "Auto Lock/Hold") to the middle position (auto lock
release) but make sure no exposure adjustment is active (no indicators on
in the viewfinder). Now fill the camera's field of view with the grey card
(illuminated as the subject will be). Now, press the "exposure" button (but
don't turn the adjustment wheel!). You'll see the camera's automatic
aperture setting (f/stop) appear in the viewfinder. Now pull the auto lock
switch down to the "Hold" setting and you'll have the correct exposure
locked in. Repeat the above whenever your lighting angles change.
Video Outdoors
Using the camera outdoors, many people find that it tends to overexpose,
and have less color saturation. What can be done? First, make sure to use
the internal ND filter when called for. According to
my measurements the TRV900 internal ND filter is very close to 3 stops
(maybe 2.8 or so).
With the internal ND filter, but normal gain (0 dB), 1/60 second
interlaced, f/4 the camera just barely saturates on a target which a
photographic spotmeter indicates is EV 13.4. This means at f/11 (which is 3
stops down) it will saturate at EV 16.4. The standard ND filters I see in
the photo store are worth 2 stops of attenuation, so with internal and a
2-stop external you will saturate at a spotmeter reading of EV 18.4, or
with internal -3dB gain about EV 19.
The highest incident reading I've been able to measure, in full sun (clear,
California day) is EV 16.1 (photo meter, assuming an 18% grey). 18% grey is
2.5 stops down from 100% so the brightest diffuse reflector (white
clapboard house, sheet of paper etc) will register EV 18.6 on a spotmeter.
However a specular reflection of the sun from a mirror-like surface would
certainly go higher.
So, you should be able to handle any natural lighting scene with the camera
as-is plus standard 2-stop ND filter. If you don't want your specular
reflections to oversaturate, or you want to open up more than f/11, you'd
need more filter strength.
Unusual Viewpoints.
I tried shooting from an airplane window at 27,000 feet over New Mexico. As
you would expect when looking through that much air, the
picture
had a
bluish cast and had low contrast, but the image overall was better than
expected. The morning sun cast long shadows that brought out the landscape
relief. Some airplane windows are clearer than others. Don't use a
polarizer; you'll just get a rainbow-colored smear (stress birefringence in
the window plastic, possibly). I also tried an infrared filter, rumoured to
decrease haze. On the TRV900 it did not give very good results, but that
camera is always less sharp on red colors. IR filters might be better with
a different camera.
American Airlines lists a number of devices in their in-flight magazine as
"operation is NEVER permitted onboard" (not just during takeoff and
landing), among them cell phones and "commercial video cameras". I assume
this has to do with FCC Part 15, class B certification (accepted for
residential use) which limits RF emissions. The TRV900 is a class B
device. I think devices which haven't been so certified are labelled "for
commercial use only" (like my Panasonic AG-1980 SVHS deck, which I am
flagrantly using in my apartment. Don't tell the FCC.)
More about lighting
From: "Carl Franklin"
Newsgroups: rec.video.production
Subject: Re: Lighting
Ryan Eagan wrote in message <36996D1F.43D@epix.net>...
I'm producing a small film and I'm using my new JVC GR-AX830 VHS-C
camcorder. What I want to get away from is that home made look. I
imagine most of that is in lighting. Any tips?
Don't know how much this will help, Ryan, but I've been using some of my
"skills" learned in still photography for my video work. A lot of the same
theory applies, and that's especially true when it comes to lighting.
So . . . here's a few "pointers" I've picked up over the years.
1. Consider the Light Source.
When it comes to photography (videography) we must recognize that there is
only 1 true "natural" source of light on our planet. That's the sun.
Everything else is either reflected light (such as off the moon or a mirror)
or artificial light. With that in mind one must also recognize that the
source of the light (either direct sun, reflected sun, or artificial light)
will have different effects on the subject.
For instance, imagine that you're sitting in the stands of a baseball park
in late August and it's 3:00 p.m. You're probably imagining harsh-direct
sunlight. Now, imagine the same scene except it's now 9:30 p.m. You've
probably substituted halogen (or other gas) lights for the sun.
Each of these light sources will affect your subject (and thereby your
"picture") in a different way. So, one must first consider the light source
when composing the photo/video. The light source can go a long way in
producing the desired effect or in ruining an otherwise great shot.
2. Consider the Light Location
Have you ever taken what you thought was going to be a great picture only to
find out later that the it looks all wrong? Chances are the light location
was wrong and it made the subject look different on film than what you
thought you were seeing when you took the picture. What was a great picture
in the mind's eye turned out to be dull and lifeless when developed on film.
A chief culprit in this problem is poor light positioning.
One of the biggest problems to arise when dealing with light positioning is
shadows. This is especially true when dealing with people's faces. Light
coming from the side will highlight those bumps and ridges on a person's
face. Likewise, harsh light from overhead will make the eyes appear to be
sunken. And lighting from too low produces a ghoulish effect that no
horror film maker would ever give up.
So, the long and short of it is that you've not only got to consider the
light source but you've also got to consider where the light is coming from.
How will that light affect your subject and the various shadows that will be
produced.
3. Control the Light if Possible
Even if you're shooting outside you can still control the amount of light
and the angle from which the light will shine on your subject. One of the
earliest lessons I got from my photo instructor was how to control light
with various gadgets. The reflective screens and other tools of photography
apply equally in videography. So . . . take some time to get to know how
you can control the light.
A great series of articles on lighting for photography is in the last two
issues (Nov/Dec. 1998 and Jan/Feb 1999) of Photo Techniques Magazine.
4. Compose your work
What this means is that you - as the artist - must compose your work just as
a painter would compose a fine painting. Don't just snap a photo or push
the "record" button on the camcorder until you know exactly what you're
shooting and why.
For me this means that I "storyboard" everything that I do. When I set out
to make a short documentary for my classroom I have a specific purpose.
Unlike shooting "home movies" I set out to shoot a "professional" video. I
script everything (with a few exceptions) and set up my scenes very
carefully.
I hope some of these recommendations are what you were looking for when you
asked for input.
Carl Franklin
carlf@dustdevil.com
http://www.dustdevil.com/ppl/carlf
Lighting equipment
From: Ken Preston
To: trv900 at onelist com
>Okay, so everyone tell me what kind of indoor/stage/studio lighting you use.
>Specifically what brands, wattages, etc, for specific lighting needs--i.e.
>for fill-lights, key-lights, spot lights, etc. I am going to be making a
>small (low-budget) movie. I need all your input. Thanks. --Ed
I think this depends on what type of movie you're making. What style, or
look, do you want to see in the finished product? How big are the sets
(or locations)? This will somewhat dictate the type of light units you
will need. Big sets sometimes equals big lights - depending on what you
need to see in the set.
I've been making some "behind the scenes" type videos of still photo
shoots. I have been using Kinoflo 4 foot lightbanks to light up the set
(kinoflo.com). The still shoot is
using strobes and the amount of light that the Kinoflos put out is more
than enough for the 900 to make very good looking pictures but not enough
light to affect the lighting on the still set. The strobes over power the
Kinos with no problem and since I'm using the daylight balanced tubes in
the Kinos, there are no color problems.
BUT.... if I was making a movie that needed more dramatic lighting, I'd
probably use tungsten lights in Chimera light banks (chimeralighting.com) for the keys
and Arri (arri.com) or Pepper lights (by LTM, ltmlighting.com) for accents and back
lighting. General set fill could be with any source bounced into a big
white card or foamcore. The Kinos could also be used for general set fill
- with the tungsten tubes.
In small rooms, I use 1000w Lowell Tota-lights in the Chimeras. I think
they provide the most even lighting inside the Chimera and hence the most
even light output from the front of the light bank. To control the
spread of the light out of the Chimera, I use the aluminum or fabric
light grids.
Here's a word of advice, rent if you can. All lighting is expensive.
Another word of advice - hire someone to light your sets (if it's not
your thing) and try to find someone that comes with their own lights.
They will probably know how to use the lights and have all the
accessories needed - like stands and gels and flags and scrims and, and,
and, and......... Someone that knows this stuff will improve the
quality of your finished product a thousand percent!
Ken Preston (koasis at earthlink net)
Dramatic Lighting: An Example
Lighting idea: #001
Title: Dramatic light for medium shots and closeups
Date: August 22, 1999
Author: Victor K. (moviemaker at sprint ca)
Equipment: 1 unit - 4' X 8' foam core or cardboard
1 unit - 250/500 watt light source with stand
1 unit - diffusion filter of your choice
1 unit - camcorder
1 unit - sharp knife
1 sheet - non-flammable, light diffusion gel
multiple candles
Instructions:
-------------------------
1. Cut squares in the 4' x 8' board.
2. Trim pieces of the light diffusion paper/gel to fit the shapes
you have cut.
3. Setup the set according to the diagram below and TURN OFF ALL OTHER
LIGHTS. The "i" represents a candle with a flame.
|
| O Subject - sitting, standing,
Light source ==> | i /|\ on a sofa, couch,
| | i bed, etc.
4' x 8' w/ cut holes | / \
| i i
4. Set shutter speed to 60th of a second.
5. Set aperture from Open to maximum F4 - F4.8 for shallow depth of
field.
6. Vary the height of the light for desired effect.
7. Dolly or pan left-right for desired effect.
8. Set white balance to yield a warmer (more orange\yellow) look.
9. Shape the coverage of the light source using barn doors (the movable
flaps attached to some lights) or shape light by wrapping it with black
foil\wrap or even aluminium cooking foil.
10. Vary intensity and coverage of the light for desired effect.
This setup will yield interesting shadows and light from the cut holes of
the board while yield nice, soft light from the diffusion gels.
Used in combination with a diffusion filter over the camera gives a
beautiful romantic light for a touching, sensitive scene.
Another option is clamping a coarse linen cloth to the board with cut holes
on the subject side. Next, put a fan on the light source side blowing
through the cut holes. This will cause the linen to move and cast shadow
play on the scene.
Victor moviemaker at sprint ca
----------------------------------------
Founder - Digital Video Group
Producer, Director, DoP, Screenwriter, Actor
http://www.geocities.com/Hollywood/Location/5272/index.htm
Simulating black and white grain with TRV900
Date: Fri, 26 Nov 1999 23:16:59 -0800
From: Victor Khong (moviemaker at sprint ca)
If you wish to simulate 8mm or 16mm black and white look and film grain
with your TRV900, you can try this.
Mount a red filter on your camera. I used a 3 f-stop Cokin #003 COEF+3
Red (A size). By using a 3 f-stop filter, you have reduced the amount of
light entering the lens. This is good because this will cause the
camera to use slower shutters speeds or use digital gain to make the
necessary exposure. The red filter also enhances certain colors in
black and white. Remember to white balance the camera WITHOUT the red
filter or the effect will be lost.
Next, set your camera's PICTURE EFFECT (that's the button on the side
behind the LCD screen) to "B&W" for black and white.
Next, if you are using PROGRAM modes, select the SPORT mode (that's the
one with the icon of a guy swinging a golf club). This forces the
camera to use a faster shutter speed to capture fast motion.
Correspondingly, the APERTURE of the camera will go into digital gain in
order to capture the image. This causes the camera to record the image
with video noise - simulating black and white film grain.
If you are using MANUAL exposure mode, then fix your shutter speed at as
high a shutter speed as you can while maintaining enough digital gain to
create visible noise in the image. This is usually achieved when gain
(the exposure beyond OPEN) is cranked above 6 db gain to 18 db gain.
The fine-ness of the visible grain will depend on how much digital gain
you trigger in the EXPOSURE of the camera.
In this instance, I find it generally easier to use the SPORTS program
mode with the red filter to achieve this effect.
If you are trying to simulate a flashback scene in black and white where
a person gets shot or killed and you want to see in in grainy black and
white in slow motion without lip syncing dialogue, then select the
TWILIGHT PROGRAM mode (looks like a candle). This will make the camera
use a slow shutter speed about 1/8 or 1/4 of a second. This will result
in a slow-shutter strobe which looks like blurry slow motion. You can
of course slow it further in editing.
If using MANUAL exposure mode, then set for a slow shutter speed like
1/4 or 1/8 of a second with the exposure set between 6 db to 18 db
gain. To reduce enough light to make these settings possible when
shooting in daylight, you may have to add a neutral density filter and
also trigger the TRV900's internal neutral density filter. If shooting
at night, then this should not be a problem.
Let me know how it works for you.
--
Victor
More about sound
Date: Wed, 14 Jul 1999 17:51:55 -0700
From: Victor (moviemaker at sprint ca)
Subject: DV audio for shooting movies: mics and mixers
Gary Grady wrote:
How do you connect the FP33 mixer to the TRV900? Does the FP33 have a mic
level output, and if not is it sufficient just to use a Radio Shack
adapter/attenuator? Also, how do you set the level on the TRV900 if
you're going to be riding level with the field mixer?
You use a professional XLR (refers to the connector) mic like the ME66
and line into the Shure FP33. The FP33 will take up to four mics (if
memory serves me right). Each mic channel has its own volume level and
a Master level for the entire output going out of the FP33. The sound
recorder operating the FP33 wears hi-quality headphones to monitor the
signal going into the mixer.
The FP33 needs to line into a BeachTek (or equivalent XLR adaptor box) in
order to convert the line level into the mini-jack mic format for audio in.
Set the TRV900 volume to a fixed input level - usually something
reasonable at about 5 out of 10. Next the levels on the FP33 are set and
your location sound recorder will dynamically adjust the levels of the
sound (if and when required) of the FP33's signal going out to the
TRV900. When shooting a DV movie - depending on the type of movie you
want to shoot and directorial\artistic style, you use your rehearsal
prior to rolling video to spot audio hotspots and know beforehand which
audio spikes (if any) which will be performed during the shot. The
rehearsal is also used to establish boom lines by your boom operator and
your camera operator.
Once the level on the TRV900 has been set, you don't touch it and use
the FP33 to adjust the signal strength going into the camera. This
makes it much easier for feature film shooting. If you are an event
videographer, this of course is much less feasible.
Lastly, the camera operator must also wear hi-quality (walkman
headphones will do also) headphones to monitor the audio signal going
into the camera. Because audio recordings on video tape are synched
together on the videotape, unlike conventional film camera audio
recordings where the audio and picture are separate, the cam-op. must
verify the audio signal going into the camera. This is ultimately the
signal that will be recorded to tape. This is because the little
connectors sometimes come loose during production, changing setups, etc.
If cam-op. does not wear headphones, the audio going into the camera may
be compromised even though the signal going to the field mixer is fine.
In DV filmmaking, some filmmakers have opted to separate the video and
audio recording. Some use DAT (digital audio tape) or Nagra or Sony's
Minidisc to record sound. In my experience so far, I have not found it
to be necessary as DV sound quality is either 12-bit or 16-bit and can
record up to 48khz which is greater than CD sound at 44khz.
The weakness of consumer DV is the RC code it uses instead of SMPTE time
code. If you need extensive post-production audio sweetening, you will
be better off laying your final cut audio to a BetaSP or Digital Betacam
with SMPTE so the sync. between your audio and video will be flawless.
Some users have opted to use a high quality boom mic mounted to the
video camera itself.
The most important thing to practice your equipment setup and
operators. Not everyone is suited to be a sound recorder or boom
operator. So find the people you will work with and practice and
listen\view your work before actual production. It will save you much
grief and heartache.
Victor
moviemaker at sprint ca
---------------------------
Writer, producer & director
for DV movies
Note: The Shure FP33A is a professional-grade, portable field
mixer. My accessories page has links
to it and some other portable mixers also. -jpb
john beale
beale@best.com
Using the TRV900
