Join Now
Join ePHOTOzine, the friendliest photography community.
Upload photos, chat with photographers, win prizes and much more for free!
Indicates the output, or power, of an electronic flash. You can use the guide number to work out the aperture or flash to subject distance by dividing either into the guide number.
Related Terms
Join Our Free Newsletter
Awards
Current Competitions
Olympus 'Portraiture' Competition - Win £1000 Worth Of Gear!
30th April 2013 - 31st May 2013
This month, to celebrate the launch of Olympus' new micro site Olympus Image Space, Olympus are giving you the chance to win £1000 worth of Olympus gear!...
Featured e2 Photo
May's Photo Month
Check out ePHOTOzine's inspirational photo month calendar! Each day click on a window to unveil new photography tips, treats and techniques.
Calibrate your monitor so you can see 16 different shades.
ePHOTOzine © 2013 Magezine Publishing
Contact Support | Contact Us | RSS | Terms Of Use | Advertise | Jobs | The Team | FAQs | Support Us | Site Map | Top