While shooting high school football last Friday night, I had a strobe lighting epiphany. The night before, I was talking to another photographer and he was helping me with using strobe to light a very poorly lit soccer field.
I do have an SB-800, so one would think I could just set it to full TTL and just fire away, getting perfect exposure everytime. Not the case, especially since I often need to fire a few consecutive shots to ensure I get the moment of contact. I don't have an external battery back, so I am severly limited in my ability to do this by the lack of power being provided to the flash and the long recycle times. The solution to this is to shoot with the flash on manual, at about 1/8th power.
I played around with this on Thursday night, but couldn't get a proper exposure, so I went back to TTL and just got what I could. Friday night was a football shoot, and I decided to try again. I set my flash for 1/8th power, set the camera to manual mode, 1/160 at about f/3.5, with an ISO of 200 and began firing away. I was able to get the full output of the flash with a very short recycle time, allowing me to fire off up to about 5 frames in succession, which is what I wanted. The epiphany came when I realized that by adjusting the aperture, I was adjusting the amount of reflected flash that was being recorded. By adjusting either the shutter speed or the ISO sensitivity, I could control the amount of ambient light being recorded. In essence, I picked an aperture that gave me a proper exposure for my subject, then set my shutter speed or ISO to give me a good, balanced, ambient exposure. As the sun went down, I had to adjust my shutter speed slower to let more light in. Problem with this is that I can't stop the action of a football game at a shutter speed below 1/160. This is where I figured out that I could adjust the ISO and would get the same effect.
The shutter speed has no effect on the amount of light being recorded from the flash as the flash is only illuminating the subject for about 1/10,000th of a second, much shorter than any shutter speed on any camera.
Lesson learned, and enjoyed!
Posted by doug at September 12, 2006 02:10 PM