Flash Question

[veronicacburges]

I have a question about using a flash. I have one for my camera and have read a lot about bounding the light off walls etc..., my question is this; what should the camera's setting be when shooting in manual mode? Is there a chart or something for different lighting scenarios?

[AnnaV]

Just experiment!

Basically the aperture will control how much of the flash light is in your photo, and your shutter speed will control ambient light.

You should have a special flash setting for your white balance.

[inkista]

Originally Posted by veronicacburges

I have a question about using a flash. I have one for my camera and have read a lot about bounding the light off walls etc..., my question is this; what should the camera's setting be when shooting in manual mode? Is there a chart or something for different lighting scenarios?

Nope. This is an "it depends" thing, much like the settings for ambient exposure.

When you take a flash photo, you're combining two exposures in one: the ambient exposure, which is the one you control with iso/aperture/shutter speed, and the flash illuminated exposure, which you control with iso/aperture/power/distance.

Your main thinking should be about how you want to balance those two exposures against each other. Do you want the ambient to be your main illumination, with your flash working only to "fill" in the shadows? Or do you want your flash to be the main source of illumination, with the ambient light completely eliminated (black background). Or something inbetween? (underexposed ambient, with flash illumination to pop the subject). All of these choices are "correct." So, finding a single group of settings that's going to work isn't the solution, as it is when you shoot without flash. This is the biggest leap in thinking you have to take when learning about flash photography.

The other thing you have to realize is that iso/aperture do double duty and affect both forms of illumination, while shutter speed ... well, shutter speed is a special case.

And this is why you also need to know your camera body's X-sync (aka Maximum sync speed). On my Canon XT, it's 1/200s. So, for any speeds below 1/200s, my shutter speed will only affect the amount of ambient coming into the exposure, because the flash burst is so much shorter than the shutter speed, effectively all of the flash illumination will register.

But above 1/200s, I have to use high-speed synch to get the entire frame illuminated evenly (i.e., the slit in my shutter is now smaller than my sensor, and only part of the frame sees the light at any given moment, as the opening sweeps across the sensor. So, without HSS, the flash burst will only illuminate the bit uncovered by the slit, and I'll get a black band at the top/bottom/both of the frame). High-speed-sync drastically reduces the amount of power I have to work with, and so my flash component gets a lot weaker if I'm going above my X-sync speed.

The upshot of all this is that you can't just expect shifting your shutter speed to have the same straightforward effect with flash that it does with ambient.

[veronicacburges]

Thank you all for getting back to me so quickly.

[Samanax]

Flash Photography Techniques