Guided Tour of a Monolight
This page describes the basics of a monolight. I'll
go through one particular model of monolight in detail, to explain the
features it has. Most monolights offer fairly similar features,
though they vary in their flash output, flash output controllability,
modeling light and modeling light controls, sturdiness and
construction quality, and perhaps other features.
Here's a monolight. It's a Photogenic 1250, a 500 Watt-second light.
As far as price and features go, it's a step or two above the cheapest
monolights, but well below the top end equipment available. It sells
for about $400.00 by mail order.
You can see the clamp on the bottom of the light, designed to go
on a lightstand. The lever on the top end of the clamp loosens
and tightens a pivot, allowing you to tip the light to point it upwards
or downwards when on a stand.
The flash tube is on the far end, covered by a black plastic
"capitol dome" looking protective device. Since the
flash tube and modeling light get very hot in use,
it's recommended to avoid touching the glass. Skin oils
will cause problems with the glass, shortening the life of
the modeling light and flash tube. If you DO need to handle
the glass, it's recommended to wear gloves and/or use a clean
cloth between your hands and the glass. I always keep the
plastic dome covering the glass during transport and storage.
You can see a carrying handle on the back of the light, along
with a control panel (details below). On the bottom of
the light, there's the AC power cord socket, a little round
fuse holder, a jack for a digital power level display (the
jack looks a bit like a telephone jack),
and a cooling fan.
Here's the control panel on the back of the light.
On the right side you see the power switch, the sync jack, and the
slave window.
Synchronization
If nothing is plugged into the sync jack, then the
slave is active. An electric eye keeps watch and fires the monolight
the instant any flash is fired in the vicinity. But if anything is
plugged into the sync jack, then whatever is plugged into the sync
jack controls the light, and the slave is inactive. The light comes
with a cord that has a PC connector at one end and a 1/4 inch plug at
the other, so the monolight can be fired directly by any camera that
has a PC socket. If you wanted to use a radio slave, a sync cord, or
any other flash triggering device, you'd plug it into the sync jack.
I usually prefer to let the built-in slave trigger the monolights, and
I trigger the slave using a small, fast-recycling flash on my camera's
hotshoe, with a #87 infrared filter taped over it. That way no cords
are attached to my camera.
In a typical studio, you just need to figure out some way to trigger one
flash, and let the others be trigged by their built-in slaves. But in
a public situation where other cameras are being used, such as a wedding,
you may want to investigate radio slaves or some other more "private"
way of triggering your flashes.
Flash and Monolight Power Controls
The two slider controls across the top control the flash power and the
modeling light power. They both offer continuous stepless control
from full power to 1/32 power. The flash control is the top one,
seen here set at 1/16 power.
The modeling light control is the bottom slider, set at 1/2 power.
There are three buttons below it to select various ways of setting
the brightness of the modeling light. When the "manual" button is
pressed, the lower slider controls the modeling light. When the
"Track" button is pressed, then the lower slider is ignored, and the
upper slider controls both the modeling light and the flash power
simultaneously (the modeling light "tracks" the flash power). Push
the track/set button one more time and you can set the point at which
the modeling light goes to full brightness. The "Full on/off" button
allows you to turn the light all the way on or all the way off. The
LEDs above the buttons tell you how the modeling light is being
controlled.
Most cheaper monolights don't offer as much flexibility in
setting the power of the flash and modeling light.
Other Controls
The "Flash Indication" is a feature which swings the modeling light
up to full brightness and down to full off a couple of times as the
flash is recycling after it fires. This feature confirms to you that
the flash really did fire, in case you missed seeing it while the
picture was being taken.
The "Test" button just fires the flash. Next to it is a readylight
that lights up when the flash is ready to fire. Since the recycle time
is only about a second and a half (quicker if you're using partial power),
you don't end up checking the readylight so often as you would on a
battery operated flash.
Here's the monolight firing into an umbrella. Note the protective
cover has been removed from the flash tube, and replaced by the
metal reflector. The two little levers on top of the light release
the reflector or protective cover. The reflector has a small hole
in it for the umbrella shaft to go through. The umbrella shaft
goes through a clamp at the bottom of the light.
Here's a close-up of the monolight's flash tube. It's covered by a
protective glass shell. The modeling light is a long narrow
quartz-halogen bulb running up the very middle. The flash tube is the
glass tube with a wire spiraled around the outside of it, encircling
the modeling light.
The bright white octoganal-shaped thing in the middle of the modeling
light is the reflection of the umbrella which was providing light for
this picture.
Some monolights use standard household bulbs for their modeling
lights. This has the advantage of easy availability, but they usually
aren't as high powered as the 250 watt quartz bulb you see here. By
the time you bounce a 100 watt bulb into an umbrella, there won't be a
lot of light to see, unless you keep your studio very dark. (There's
not an excessive amount of light from this 250 watt bulb, either.) The
small quartz-halogen bulb allows for a more compact head than a
standard household bulb would allow.
Comparison to Battery Operated Flash Units
The main differences betweeen
the monolight and a battery operated flash
such as a Sunpak 383 flash unit are:
-
The monolight has a modeling light, a 250 watt quartz-halogen
bulb that lets you previsualize the effect of the lighting.
-
The monolight mounts directly to the lightstand, and an umbrella
mounts directly into the monolight. In other words, it eliminates the
need for an umbrella clamp, but it obviously can't be used on a
camera's hotshoe.
-
The monolight has a slave built-in, eliminating the need for
any extra slave or sync cord.
-
The monolight is more powerful. My light is 500Watt-Seconds, and this
gives me about four stops more light (sixteen times as much light) as
the GN 120 Sunpak flash unit at full power into similar umbrellas.
Watt-seconds and guide numbers aren't directly comparable, though, so
this comparison doesn't mean that all 500Ws monolights will be four
stops brighter than GN 120 flash units.
- The monolight recycles faster, doesn't use
batteries, and is more adjustable in light output.
- The monolight has no metering facility or autoexposure facility whatsoever;
the assumption is you'll use it with a flash meter.
-
The monolight costs about five or six times as much as a cheap battery
operated flash (but only a little more than a top-of-the line
dedicated TTL flash), is much heavier, and requires AC power.
Further resources for more sophisticated systems can be found on
http://www.photo.net/photo.
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