Exposure Table for the EOS 430EX in Manual Flash Mode

pathfinderpathfinder Drive By Digital Shooterwestern IndianaSuper Moderators Posts: 14,620 moderator
edited April 4, 2008 in Technique
I have been ruminating on my promise to Icebear to repeat his color balancing evaluation of the Expodisk versus the WhiBal and other balancing gadgets.

In the meantime, I sat down and worked up an exposure table for a Canon EOS 430ex in straight on frontal flash at 50mm zoom at ISO 100. I chose the 430ex because it is smaller and easier to pack for the travelling, and offers enough fill light to be very useful out of doors.

I mounted the flash on a tripod, and measured the distance to my Sekonic 358 with a tape measure and wrote down the readings. The meter was set to assume a shutter speed of 1/200th to minimize ambient light. I shot this in my garage which has white walls, so the values may be a little brighter than they would be out of doors, but I suspect they are pretty close.

So here are the tables

One point of interest is that exposure for bright sunlight at ISO 100 at f11 is 1/200th sec. So any distance the flash is set for smaller apertures than f11 ( f 16, f 18 , f 22 or f29) means that at those distances and power settings the flash is brighter than full sunlight, and thus the sun can be used as fill with the flash as main light in a cross lighting arrangement.

The table is only done for ISO 100, but ISO 200 would be 1 stop smaller for each distance, and ISO 400 would be 2 stops smaller, etc. Or the same aperture can be used, but the flash distance would be moved 2 stops for ISO 400 eg 4 feet -> 5.6 feet -> 8 feet, or 8 feet -> 11 feet -> 16 feet for a 2 stop decrease in power.

An Impact 42 inch folding reflector with a silk scrim can be placed in front of the flash as a diffusion panel with the cost of about 1 stop of light if a bigger, softer, source of light is needed.

Pathfinder - www.pathfinder.smugmug.com

Moderator of the Technique Forum and Finishing School on Dgrin


  • ziggy53ziggy53 Still learnin'still lovin Super Moderators Posts: 22,399 moderator
    edited April 3, 2008
    Nice, Very nice! thumb.gifthumb
    Moderator of the Cameras and Accessories forums
  • rwellsrwells Let the shootin' begin... Registered Users Posts: 6,084 Major grins
    edited April 4, 2008
    I just found this "The Photographic Cheat Sheet" today.

    Look on the right side of the page, then click on the Cheat Sheet.

    Impressive thumb.gif

    BTW, thanks Pathfinder for your hard workclap.gif
Sign In or Register to comment.