how to shoot night portraits with background in exposure

I want to shoot a portrait at night time with the background (city lights) in xposure, i have 2 soeedlites at my discretion. I want to be able to freeze the subject with a flash and get the background (night city lights & ocean)

can someone help me? shooting with 5d mkii & 24-105 & 50mm

Best way I can think of is 2 shots, one for subject and one for background, then layer the subject onto the background in PS. Remember to manual focus and keep the focus the same for your subject and background shots so you can achieve your desired bokeh/dof.

Thats what I was thinking, How ever is there any other way the doesnt involve as much pp

it's really quite simple, especially if your background in the shot with your subject is mostly or completely black, then it's just magic want tool, delete the black background, overlap on background, done.

BTW, are you on pbnation? Just noticed your username.

You can do it with one shot can you not? Shoot a long exposure which exposes the background, then put your flashes on second curtain and hit the flash at the end - freezing the subject?

I completely forgot about second curtain..do that.

Something like this http://www2.metrotimes​.com/30/08/artists/Alc​ott.jpg

paintballkidz wrote in post #12956048
Something like this http://www2.metrotimes​.com/30/08/artists/Alc​ott.jpg

That is a composite. One image exposing for the subject, and a second image exposing for the 'background'. Then put together in photoshop.

Why wouldnt you just meter for the background, putting your subject into shadow, then use the flash to bring the subject up to equal or slightly brighter than the background?

C.Michael wrote in post #12956021
You can do it with one shot can you not? Shoot a long exposure which exposes the background, then put your flashes on second curtain and hit the flash at the end - freezing the subject?

JakAHearts wrote in post #12957739
Why wouldnt you just meter for the background, putting your subject into shadow, then use the flash to bring the subject up to equal or slightly brighter than the background?

That's what I said, and it definitely would be the easiest way. No need for stuffing around in PS.

I was agreeing. Dont be afraid to use high ISO to get an acceptable shutter speed too.

JakAHearts wrote in post #12957739
Why wouldnt you just meter for the background, putting your subject into shadow, then use the flash to bring the subject up to equal or slightly brighter than the background?

Yes, definitely. Meter for the background, flash for the subject. With proper use of the flash, there's no need to use multiple exposures or compositing .

(Of course, special circumstances notwithstanding... if you want to put your subject into the middle of a busy street, as shown in the link above, then multiple exposures are a great idea).

First, with your subject out of the frame, meter to expose the background. You probably will need to let the camera's meter think it's slightly underexposed, to get some of that ambient nighttime feeling. Take some test shots with the subject out of the frame, and see how they look. Remember to check the histogram; if you're in a dark place while looking at the LCD, the image will seem brighter than it actually is.

Then put your subject in the frame. Use the exact same camera settings as before, only this time use the flashes to light your subject. You said you had two Speedlights, right?

Use the first light as your main light, at an angle to the subject - the general rule is 45 degrees above, and 45 degrees to the side. If you have a modifier on the main light, such as an umbrella, put it as close to the subject as possible without actually getting in the frame. Depending on the camera settings for your background exposure, you'll probably need a moderately low power setting.

Use the second light as your fill light, at a very low power setting, near the lens axis.

If you had a third light, you could set it as a rim light or a hair light.

Alternately, you could use your second light as a rim or hair light, and use a reflector in lieu of a fill light.

The problem is I will be shooting at night, when its very dark out the background is the city lights/ocean. I want to be able to get a nice long exposure of the background while freezing the motions of the subject. I have 2 speedlites 580 & 430 that will be triggered with a yongnou triggers.

It may help to think of flash photography as two separate exposures with one press of the button.

You have the exposure that you get from the ambient lighting - this is your background, and the exposure comes solely from the camera's settings (ISO, aperture, shutter speed). Then you have the exposure that comes from the flash - this is your subject, and the exposure is affected primarily by the flash power, and also by the aperture and ISO. The flash exposure is NOT affected by the shutter speed, as long as you don't use a shutter faster than your sync speed (1/200) - which you won't, because you're doing a long-exposure background shot.

If you use a fast shutter speed (up to 1/200) you can take a picture of just your subject, and the background will probably be solid black, depending on your ISO and aperture. If you keep the same aperture and ISO, you can use a longer shutter speed to increase the exposure of the background, but the exposure of your subject will essentially be the same - the flash is an instantaneous burst of light that will be the same regardless of shutter speed. This is called "dragging the shutter."

So, you have the shutter speed that affects the background only; the aperture and ISO which affect both the subject and the background; and the flash power/positioning that affects only the subject. Use those four variables to get the exposure you want for both the subject and the background.


One other note: If there's NO ambient light falling on your subject, you can use any shutter speed longer than 1/200. Heck, make it a full second, five seconds, thirty seconds. However, if there's a little bit of ambient light on your subject, you'll need to be a little more judicious with your choice of shutter speed, or else you'll get "ghosting" around the edges of your subject. Setting the camera's flash control to "2nd curtain" will help improve the appearance of any ghosting, by causing the ghost trails to lead up to the subject, instead of away from the subject.

I'm also assuming you're using a tripod for the exposure. You'll need it for the background, but it won't make a difference on the subject - the flash is faster than any camera-shake anyway.

nathancarter wrote in post #12962845
If you use a fast shutter speed (up to 1/200) you can take a picture of just your subject, and the background will probably be solid black, depending on your ISO and aperture. If you keep the same aperture and ISO, you can use a longer shutter speed to increase the exposure of the background, but the exposure of your subject will essentially be the same - the flash is an instantaneous burst of light that will be the same regardless of shutter speed. This is called "dragging the shutter."

Won't the ambient light from the long exposure infect the flash exposure?

I would think that in order for this to work, the subject area must be completely black during the long exposure sans flash.