If you have been looking into flash photography, you will notice a term often used, off-camera flash. You may wonder how a flash not sitting in the hotshoe of your camera is to be triggered in sync with the shutter press. This is where triggers come into use. There are two main types of wireless triggers are optical and radio.
Optical triggers operate as their name suggests, optically. When the sensor inside the trigger senses an impulse of light, usually caused by another flash, a circuit is closed and the flash is triggered. Optical triggers are the most basic in wireless triggering and can be the cheapest. The triggers are limited in range, requiring the sensor to be able to see the flash from other flashes. Also, bright lights or other flashing lights could interfere with the reception.[1-3]
Radio triggers are the other usual option. They can get more range than optical triggers and you aren't limited by corners or out of sight flashes. Radio triggers can get a range of 1600 feet, giving you plenty of leeway. Because a radio signal is being sent between two units, they do require batteries to use. With many brands and options available, prices can vary widely. The lower end units are usually Chinese made triggers that work at about 30 feet. One of the more popular brands among the professionals are Pocket Wizards ®. They are one of the pricier options available but have great range and reliability.[4]
Sources::
[1] Fulton, W. (n.d.). How to trigger speedlights Off camera.Scanning Basics 101 - All about digital images. Retrieved March 25, 2011, from http://www.scantips.com/lights/trigger.html
[2] Smart Optical Slave Flash Trigger - Digital Photography Tips and Techniques. (n.d.).Digital Photography Tips and Techniques. Retrieved March 25, 2011, from http://dptnt.com/2010/03/smart-optical-slave-flash-trigger/
[3] Hobby, D. (2010, July 28). Strobist: Understanding Optical Slaves, Pt. 2. Strobist. Retrieved March 25, 2011, from http://strobist.blogspot.com/2010/07/understanding-optical-slaves-pt-2.html
[4] Hobby, D. (2006, March 21). Strobist: Lighting 101: PC Cords and Pocket Wizards.Strobist. Retrieved March 25, 2011, from http://strobist.blogspot.com/2006/03/lighting-101-pc-cords-and-pocket.html
I have used off camera flash before. It was pretty handy to get different lighting fairly easily and it certainly makes more interesting lighting situations possible than just the flash a lot of cameras come with.
ReplyDeleteI believe I used an optical one during a photo shoot a year or two ago and I enjoyed it. Other lights did interfere sometimes, like you mentioned. It took a few attempts for everything to work correctly.
I did not know a lot about radio trigger previously but they do sound pretty neat! I might try out that type of trigger sometime. Thank you for the good information.