Off Camera Speedlights
by Dennis Ruga
Caveman Camera Club
April 21, 2010
The following assumes that we are using speedlights in MANUAL MODE.
Key: When shooting with flash, we have to account for TWO separate exposures:
- One for the natural light (at times, underexposed to create shadows)
- One for the flash exposure (used to fill the shadows)
- F/Stop controls the flash exposure
- Shutter speed controls the ambient light
What can I do with just ONE simple strobe?
Use it in conjunction with natural light, as the main/side/backlight to give you nearly studio lighting and now light a subject with “two” lights.
COLORING LIGHT
Gels are used to both color/warm light, & balance color temperature of existing “bulb” light (incandescent/fluorescent)
SOFTENING & HARDENING LIGHT
Closer to the bounce/umbrella, the softer the light. Using a “snoot” to focus the beam hardens the light.
FOCUSING LIGHT
A tube or “snoot” over the strobe can focus the light beam, or create a spotlight effect. (also used as hair lights)
MOTION ANALYSIS
Manual flash power, when turned down, uses very short flash durations, (10-25,000 sec.) this is the equivalent of a using an extremely high shutter speed. Use it to freeze motion and illuminate at the same time, unlike just a high shutter. Experiment with it to reveal what you can’t normally see.
PRACTICE CREATING LIGHT:
You can now carry all the light you need in your pocket to both fill existing light or be the all light in your shot.
When using multiple strobes. Shoot off one at a time to see the effect & determine proper exposure for each. Then turn on all for the final shot.
Use snoots/backlights/fill lights to “shape” flat objects.
Remember the cabbage shot? That’s how it was created.
REMOTE TRIGGERS
Enable you to hide and/or set lights off from 200ft +.
Stash in night shots. Long time exposures can now also render defined clarity with a subject in them. Transmitter required on hot shoe. Receiver required on flash.
Paul C. Buff remote triggers
(my recommendation for performance/value. Call if you have questions before buying)
http://www.alienbees.com/cybersync.html
CyberSync™ Trigger Transmitter (CST) $59.95 (mounts on hot shoe)
CyberSync™ Battery Powered Trigger Receiver (CSRB) $69.95 (connects to each flash unit*)
* see link above to verify flash connection/hot shoe required for your flash.
GET STARTED EQUIPMENT:
Please NOTE: I chose the equipment below for maximum portability/backpacking. If this is not your need, you might want larger umbrellas, etc.
- Your Speedlight
- Light stand & clamp
- Umbrella
- Gels
- Manfrotto Umbrella Bracket/Swivel 026
http://www.mpex.com/browse.cfm/4,430.html
Flash Gels
- To correct color & add effects
Compact Light Stand
- Manfrotto 5001b Nano Light Stand (3373/001b)
http://www.mpex.com/browse.cfm/4,4944.html
BALANCING FLASH with Ambient Light: DAYLIGHT
Indoors: interiors to about 1/60th at f/4 at ASA 400. Keep the aperture at f/4 and go to a 250th of a sec., or go to 125th at f/5.6. Whatever.
The idea is to build an ambient-light-only exposure that would result in an underexposure of 2 stops.
That will be your lighting ratio. You can choose another ratio (and you should experiment) but 2 stops is a good starting point.
Move your lights accordingly.
Outdoors:
Step one: Think of the sun as your main light, and your strobe as a secondary light. Set your camera at the highest shutter synch speed (i.e. lowest aperture) to ease the burden on your flash. Now, get your base (ambient) exposure.
Call it a 250th at f/11 at ASA 200.
Now, with your strobe on manual and on a stand, set it to somewhere around a quarter to half power if you are working close.
If you are not lighting a large area (and you usually are not) zoom the flash to a 70mm or 85mm lens angle to make it even more powerful.
Pop a test frame and eyeball it.
If your flash-lit area is too bright, dial the flash down or move it back. If it is too dark, dial it up or move it forward.
For Nikon users ONLY:
Nikon CLS: wireless capability ALREADY built into your camera with Nikon strobes.
Nikon has their own completely wireless capability with most cameras after the D 70,
and their flash units.
http://www.kenrockwell.com/nikon/ittlslave.htm
I would be happy to show anyone who needs a demo.
How Light Changes with Distance/Moving Flash/Altering Flash Power
Illumination Falloff:
The Inverse Square Law
It’s useful to know a little about the inverse square law especially when using flash or studio lights. Basically all the inverse square law says is that an object that is twice the distance from a point source of light will receive a quarter of the illumination. So what it means to us photographers is that if you move your subject from 3 meters away to six meters away, you will need four times the amount of light for the same exposure. This can most easily be achieved by opening the lens aperture two f-stops or using a flashgun that is four times as powerful.
CHALLENGE:
Try to use flash in conjunction with natural light in your next great shot!
I would be happy to answer anyone’s questions or help them out as necessary.
Dennis Ruga
djruga@ix.netcom.com
http://ruga.zenfolio.com
660-9168