In a couple of weeks I'll be taking individual photos of students in my daughter's dance class. I thought this was the perfect excuse to buy some more gear and try my hand with off-camera flash. I've taken some test shots and would be very appreciate of forum members' feedback on how I might improve.
The attached photos are sooc, except I boosted the contrast slightly in DPP. Equipment used: Canon 7D with on-camera 580EX II and two off-camera Yongnuo 560 IIs. The last photo shows the setup: on-camera flash bounced to camera left and off-camera flashes on either side of the seamless white background. Camera and flash settings: 1/250, f/5.0, ISO 800, on-camera flash at full power, and off-camera flashes at 1/8+0.5 power.
I see at least two issues with the test shots. First, I think the flashes lighting the background are reflecting toward the camera and washing out the picture just a little. This goes away if I reduce the power on the off-camera flashes, but then the background doesn't blow out.
Second, in each photo, there is a shadow just behind the subject, almost as if there were a wrinkle in the background -- but the background seemed quite smooth to me. You can see this on the pull back shot, too.
Not sure what to do about either of these issues.
Also, I'd like to lower the ISO, but I'm already at full power with the on-camera flash and don't want to sacrifice depth of field. Do I need a soft box to accomplish this or is there something I'm missing.
I really appreciate any advice. I've pretty much reached the limit on my budget for photo equipment, so economical advice would be especially helpful.
Thanks,
Justin



Comments
The first thing you'd want to do is remove the flashes from behind the background and position them in front, at an angle where the light does not reflect back to the camera (remember the law of reflection says the angle of incidence equal the angle of reflection).
My 1st suggestion would be to flag the speed lights. The side closest to the camera should be blocked by nothing more that a piece of black construction paper if that's all you have access to. In a pinch I have used index cards.
The black spot on the background is probably just an under exposed area of the background due to the very fast fall off from having the light that close to the background. Try making sure the speed lights are at or nearly at the widest end of there zoom. Maybe put the speed lights on chairs and try feathering the aim of the light till you get an even pattern. Getting them pointing downward instead of up will help. I have very limited room indoors and have the speed lights about 5 feet from the background at the same power settings to clip the back ground to white. If its a little under you can clip it the rest of the way in post and mask your subject.
It looks like you have some room there-move your subject away from the background. At least 5 feet to HELP avoid the contrast killing spill (the flags will help somewhat with that issue) A white background is very reflective. Use your lens hood if you did not.
I am not familiar with the canon setup you are using. I presume your on camera flash is being used to trigger your background lights? The ocf will not give you the spread of light to keep the background in front of your subject white or be completely flattering.
I shoot the same setup at 1/200 (or whatever kills the ambient but stays under Max sync) 200 iso at 6.3 -7.1. I use an umbrella and a speed light in place of the ocf. Those are just ref numbers and not really anything you should try to repeat. I am confident you have enough flash power there to do it with out being at 800 iso. I hope I helped even the smallest amount.
Justin
I made three changes to the setup. First, I flagged the two flashes lighting the background. Second, I moved the flashes lighting the background about five feet closer to the camera. Third, rather than point the flashes directly at the background, I angled each flash toward the opposite corner of the background. The result is below.
Regarding improvement ... About two-thirds of the way down the photo the white background becomes not so white. This is the position of the flash units lighting the background. I think one way to mitigate this issue would be to follow Zach Arias' tutorial (see link above) and use 4'x8' white tile boards.
Finally, I'll mention that I'm lucky to have a model who accepts payment in kind -- fruit snacks in this case
Justin