Curtis N
30th of July 2006 (Sun), 12:08
While discussions will go on forever over which flash modifier is best, a point often made about the Sto-Fen product is that it wastes light. So I decided to try the Omni-Bounce and compare it to other options in quantitative terms only.
The method I used was to set the flash at full power in various configurations, shoot a neutral gray target and adjust the aperture to get a centered histogram spike.
The indoor tests were conducted in a 13 ft. x 15 ft. room with an 8 ft. high white ceiling. The walls, floor and furnishings were mostly dark-colored. The camera and target were about 5 feet high.
While some people (including me) think it's nuts to use the Omni-Bounce outdoors, nevertheless there are those who claim that it somehow "softens" the light in that environment. So I included outdoor tests which were conducted at night.
Keep in mind that the flash zoom settings are based on the field of view of a 35mm film camera. So for example, when the flash is zoomed to 105 mm, it will cover a 65mm lens on a 1.6x camera.
My observations/conclusions:
1) In either environment, the Omni-Bounce provided the same amount of light as using the 17mm wide panel on the flash.
2) Regardless of angle, the Omni-Bounce was brightest when the flash was zoomed to 28mm. For this reason I used the 28mm setting for all tests with the Omni-Bounce attached.
3) I was surprised that there was no measurable difference in the outdoor vs. indoor readings with the Omni-Bounce pointed at the target. I expected the ceiling bounce effect to provide a bit more light indoors.
4) The guide number calculations (multiply the aperture x 10) with direct flash were about 1/3 stop less than specified in the flash unit's documentation. It's fairly common knowledge that flash unit manufacturers exagerate their power to some extent.
5) For those who use the Omni-Bounce for fill flash in the sun, keep in mind that it dramatically reduces your range. My tests indicate a guide number of 63 feet with the Omni-Bounce. This is only about a stop more than the built-in flash! In the sun you'll need an aperture around f/10 at 1/250 shutter. So you'll have an effective range of only 6.3 feet for full flash exposure or about 9 feet at -1 FEC. You'll get about 1/3 stop less with the 430EX and 1/3 stop more with the 580EX.
The method I used was to set the flash at full power in various configurations, shoot a neutral gray target and adjust the aperture to get a centered histogram spike.
The indoor tests were conducted in a 13 ft. x 15 ft. room with an 8 ft. high white ceiling. The walls, floor and furnishings were mostly dark-colored. The camera and target were about 5 feet high.
While some people (including me) think it's nuts to use the Omni-Bounce outdoors, nevertheless there are those who claim that it somehow "softens" the light in that environment. So I included outdoor tests which were conducted at night.
Keep in mind that the flash zoom settings are based on the field of view of a 35mm film camera. So for example, when the flash is zoomed to 105 mm, it will cover a 65mm lens on a 1.6x camera.
My observations/conclusions:
1) In either environment, the Omni-Bounce provided the same amount of light as using the 17mm wide panel on the flash.
2) Regardless of angle, the Omni-Bounce was brightest when the flash was zoomed to 28mm. For this reason I used the 28mm setting for all tests with the Omni-Bounce attached.
3) I was surprised that there was no measurable difference in the outdoor vs. indoor readings with the Omni-Bounce pointed at the target. I expected the ceiling bounce effect to provide a bit more light indoors.
4) The guide number calculations (multiply the aperture x 10) with direct flash were about 1/3 stop less than specified in the flash unit's documentation. It's fairly common knowledge that flash unit manufacturers exagerate their power to some extent.
5) For those who use the Omni-Bounce for fill flash in the sun, keep in mind that it dramatically reduces your range. My tests indicate a guide number of 63 feet with the Omni-Bounce. This is only about a stop more than the built-in flash! In the sun you'll need an aperture around f/10 at 1/250 shutter. So you'll have an effective range of only 6.3 feet for full flash exposure or about 9 feet at -1 FEC. You'll get about 1/3 stop less with the 430EX and 1/3 stop more with the 580EX.