getting background underexposed, subject properly exposed

Can anyone lend any tips on how to do this?

I plan on shooting with an ST-E2 on the hotshoe and then 580EX II and 430EX on lightstands. I would like my subjects to pop out from the background more by underexposing the background and then exposing the subject correctly with flash. This is during normal day time, not during the night.

I originally thought I would use Manual mode on the camera and meter the background and adjust settings so the light meter reads -1 for the background. For example, if the background reads correct exposure at f/2.8 and 1/800, then I would use a setting of f/2.8 and 1/1600 to underexpose the background by one stop. My question is how to do I get the subject to be properly exposed? I do not have a flash light meter, so is there a quick way to get the off camera flash to expose the subject correctly?

Originally I was going to put the camera in Manual mode and underexpose the background by one stop like above. However, when you use Manual mode the ST-E2 will transmit ETTL to the flashes and the flashes will expose the scene normally. This is because the flashes are putting out enough light to correctly expose the scene you are shooting...thus me making sure the light meter reads -1 for the background means nothing at all! The flashes will just put out more light to light up the background to proper exposure...

Does this mean I need to put my flashes into manual mode? Is there a way to avoid trial and error? Do I need a flash/ambient light meter to make this easier to do?

thanks in advance..I'm so clueless...

If you're using E-TTL it'll be automagic. Otherwise you're gonna have some trial & error without a flash meter. Flash has nothing to do with the background unless they're positioned to place light on the background, whether it's spilled or aimed directly.

Hi,

I don't use TTL neither a meter, not that I'm against it, I just don't have one.
In your case, I'd start by shooting and finding the right exposure for the background. Once I have that (I'm still in M mode), I would place the subject in front of the camera and try to guess the right flash exposure (also in manual) and by powering down/up the flash or changing the proximity of the flash and subject, I'd get the right foreground as well as background.

cdifoto wrote in post #7820487
If you're using E-TTL it'll be automagic. Otherwise you're gonna have some trial & error without a flash meter. Flash has nothing to do with the background unless they're positioned to place light on the background, whether it's spilled or aimed directly.

In my experience flash exposes the scene automatically in M mode on the camera. I've used bounce flash off white ceilings, and it doesn't really matter aperture and shutter speed I put in, it'll expose the same way. The only thing I can think of that wil drop the background down is a -1 flash exposure compensation, but that takes the subject's lighting down one stop too.

I guess what you're saying is to move the flashes so they are closer to the subject, and just by proximity they will light the subject up more than the background?

And because the flash is hitting the subject directly, this will cut down the contribution that ambient light gives to the subject? If I think about it in portions...the flash portion and the ambient light portion will add up to give correct exposure of the model, but since the background isn't getting the flash portion's contribution, it will be underexposed?

If you are not using flash units to illuminate the background try this.

1) Increase the distance from the subject to the background

2) Decrease the distance between the main and fill light and the subject.

Enjoy! Lon

AliinDXB wrote in post #7820502
Hi,

I don't use TTL neither a meter, not that I'm against it, I just don't have one.
In your case, I'd start by shooting and finding the right exposure for the background. Once I have that (I'm still in M mode), I would place the subject in front of the camera and try to guess the right flash exposure (also in manual) and by powering down/up the flash or changing the proximity of the flash and subject, I'd get the right foreground as well as background.

thanks for the tips. since i tend to change locations or move the model to different poses in different areas a decent amount when i shoot my portraits outdoors (and most of my shoots are outdoors), i guess i'm asking if theres any quick and dirty way to do it isntead of guessing each time i move the model. i'm open to using light meters, i just am clueless as to how to use them, and how to combine a info i'd get from the background reading and the model reading and the flash reading or whatever else!

put your shutter speed at 250, it will pretty much drown out your background
expose for your subject, and the background will automatically "go away" to give you that pop

Sfordphoto wrote in post #7820516
In my experience flash exposes the scene automatically in M mode on the camera. I've used bounce flash off white ceilings, and it doesn't really matter aperture and shutter speed I put in, it'll expose the same way. The only thing I can think of that wil drop the background down is a -1 flash exposure compensation, but that takes the subject's lighting down one stop too.

Actually the flash is exposing the subject. It doesn't care about the scene overall. The reason you're getting the entire scene exposed that way is because you're bouncing the flash and it HAPPENS to be a small enough area for the flash to cover. When you use direct flash though, it's more apparent the way the metering works. The flash goes for the subject and the camera is bringing up or down the ambient (background) depending on the settings used.

Sfordphoto wrote in post #7820516
I guess what you're saying is to move the flashes so they are closer to the subject, and just by proximity they will light the subject up more than the background?

It would be more helpful to get both the subject and the flashes further from the background.

Sfordphoto wrote in post #7820516
And because the flash is hitting the subject directly, this will cut down the contribution that ambient light gives to the subject? If I think about it in portions...the flash portion and the ambient light portion will add up to give correct exposure of the model, but since the background isn't getting the flash portion's contribution, it will be underexposed?

Yeah. Depending on your camera settings though. You can use an ISO and shutter speed combination that brings the background up (it's called dragging the shutter).

i guess the one stop difference in light could be done as follows?

get a meter

meter the combination of flash and ambient light in the background...say correct exposure for the background is f/2.8 at 1/800

meter the combination of the flash and ambient light on the model, mess with the flash settings until correct exposure for the subject reads as f/2.8 at 1/1600 (less exposure time needed because flash is directed more at model than the background)

this would yield a underexposed-by-1-stop background if i put my camera in manual and shot f/2.8 and 1/1600?

If you had a flash/ambient meter it would be super easy. Meter your background. Then meter and adjust your lights until they read a stop up from the background.

An alternative if you go all manual with the lights and camera is to simply meter your lights, get your aperture and ISO set up, then use a shutter speed that puts the background where you want it exposure-wise. You gotta keep the shutter at or below sync though, which is 1/200th or 1/250th depending on your camera (with exceptions of course like the 1/500th 1D original, etc).

cdifoto wrote in post #7820562
Actually the flash is exposing the subject. It doesn't care about the scene overall. The reason you're getting the entire scene exposed that way is because you're bouncing the flash and it HAPPENS to be a small enough area for the flash to cover. When you use direct flash though, it's more apparent the way the metering works. The flash goes for the subject and the camera is bringing up or down the ambient (background) depending on the settings used.


It would be more helpful to get both the subject and the flashes further from the background.

Yeah. Depending on your camera settings though. You can use an ISO and shutter speed combination that brings the background up (it's called dragging the shutter).

thanks a lot cdfolito. Using a higher ISO and/or slower shutter will bring the background up?

Sfordphoto wrote in post #7820580
thanks a lot cdfolito. Using a higher ISO and/or slower shutter will bring the background up?

Yes but remember if your flashes are in manual you can't adjust those on the fly because your lights are locked in for a certain ISO and aperture. Changing those means you have to compensate your lights accordingly.

cdifoto wrote in post #7820579
If you had a flash/ambient meter it would be super easy. Meter your background. Then meter and adjust your lights until they read a stop up from the background.

An alternative if you go all manual with the lights and camera is to simply meter your lights, get your aperture and ISO set up, then use a shutter speed that puts the background where you want it exposure-wise.

Just want to make sure I understand correctly...when I meter the subject the meter will read the combination of the flash and the ambient light on the subject correct? My understanding is that some meters will actually split the reading up and tell you each light sources contribution (flash component, ambient component)...but the main thing is it will give you a shutter/aperture/iso combo to use for correct exposure? Never used a light meter, so excuse my ignorance and thanks for your patience.

The bolded part...upon using faster shutter speeds, the flashes will put out more light to compensate? I'm assuming we are still using ETTL mode. This light won't hit the background and thus the background will be underexposed is my understanding.

I would think metering (with the camera) the BG at a stop under exposed and then adjusting the FEC for the flash would bring the subject up nicely. Outdoors in daylight could present issues with getting the BG proper while still keeping within the parameters of the flash units (max sync speed) but high speed sync is also an option.

Or perhaps we have your BG figured wrong? I assume trees or buildings, etc...rather than a studio type BG.

cdifoto wrote in post #7820594
Yes but remember if your flashes are in manual you can't adjust those on the fly because your lights are locked in for a certain ISO and aperture. Changing those means you have to compensate your lights accordingly.

understood. in your experience is it best to shoot with flashses in ETTL or manual when you are using a light meter to get a background and subject reading?