Metering bounced flash

<p>I have a flash mounted on a tripod pointed at a flat white celing(about 3 ft below it). I will also be using an on camera flash that has no tilt or swivel. I will be firing the off camera flash with an optical slave. My question is this: If I point the dome of my flash meter toward the celing from the subjects location & fire the off camera flash with its "test" button, will I be measuring the "ambient" light that the flash produces? Can I then set the on camera flash a stop or so lower & be assured of a good exposure? I'm using film & don't have the immediate feedback of digital.<br>

Thanks in advance Jim</p>

<p>Point the dome straight at the light sources individually (i.e., once at the ceiling and once at the camera) to gauge your ratio, making changes to power settings and distances to get the ratio where you want it, then with both flashes on, point the meter at the camera.</p>

<p>Van</p>

<p>"then with both flashes on, point the meter at the camera."<br /><br />I would point the dome at the main source of illumination, which would not be the camera if the on-camera light is the weaker of the two.</p>

<p>Thanks for the answers. Here's what I am getting for readings.</p>

<p>Dome pointing upward from subjects position.... F8 & firing off camera flash only.</p>

<p>Dome pointed toward camera.... F5.6 with on camera flash only</p>

<p>Dome pointed toward camera & firing both flashes ... F8</p>

<p>Dome pointed upward at subjects position & firing both flashes .... F11</p>

<p>It looks like I should be using F8</p>

<p>Yes. Also drop the on camera flash at least another stop. You'll have way too much fill at -1.</p>

<p>It depends what effect you want. I recommend you use different settings and test. With experience you should be able to predict results up to a certain extend. But with film, the use of a polariod is important for detailed lighting control. Also using on camera flash for fill gives you ungly fill shadows. It may be better to get a swivel head flash, if that's the way you want to go. I usually trigger my lights with bounce flash, unless that would give me too much fill for an extremely low key photo, or it is unreliable, for instance in bright sunlight.<br>

If you have one off-camera flash available, it is probably best to get fill from a reflection screen. (I regularly use one of those silvery screens that are sold for keeping heat out of a car. For a softer effect a white bedsheet gives good results.)</p>