Need Advice for Portraits with a City in Background

I need some advice on taking a few portraits in front of a city at night (specifically Pittsburgh on Mt Washington in case you know the area). I am working with an off camera flash 430ex ii, either a 50mm f1.4 or 24-70 f4 and the flash can be in a softbox if needed. I want the subject to be properly exposed but also get some sparkling city lights in the background. Going out to play with this setup tonight so any advice you have on what camera or flash settings would be appropriate would be appreciated. First time using off camera flash at night thanks for the help!

You will need a tripod and to 'drag the shutter' meaning the flash will fire and freeze your subject, but then the shutter needs to stay open to properly expose the city. Your subject will need to stay still.

So figure out the shot by first figuring out the exposure needed for the city, then adding the model and appropriate flash level for exposure and you got it. You may want to bump the iso a bit so the exposure isn't too long.

^ This advice is a s good as it gets.

Good luck OP, let us know how it comes out!

Bryan

This is where you need to get a grasp on the idea that a flash photo has 2 different exposure values in one shot. The first value is the ambient value, basically what your camera records without the flash. In this case its the cityscape. So you need to start by in effect setting up for a landscape photo. Lets guess that you can get the city lights to look good at 1/5 of a second @ f8 ( just a hypothetical ) in manual mode. Then you add the subject and turn on the flash. If you are using ETTL flash it will get close to correct exposure, then dial in flash exposure compensation to fine tune. If you are using manual flash then start at low power 1/16 or so and add more power each test shot until you are happy. Keep in mind that in these circumstances shutter speed has almost zero effect on the flash exposure. So you can adjust the background exposure by lenghthening or shortening the shutter speed without changing anything else. If you change the aperture it will change both the background and the flash exposure so its best to pick the aperture you want for creative reasons and adjust shutter speed and flash power to get the balance between the two elements.

gonzogolf wrote in post #17255978
This is where you need to get a grasp on the idea that a flash photo has 2 different exposure values in one shot. The first value is the ambient value, basically what your camera records without the flash. In this case its the cityscape. So you need to start by in effect setting up for a landscape photo. Lets guess that you can get the city lights to look good at 1/5 of a second @ f8 ( just a hypothetical ) in manual mode. Then you add the subject and turn on the flash. If you are using ETTL flash it will get close to correct exposure, then dial in flash exposure compensation to fine tune. If you are using manual flash then start at low power 1/16 or so and add more power each test shot until you are happy. Keep in mind that in these circumstances shutter speed has almost zero effect on the flash exposure. So you can adjust the background exposure by lenghthening or shortening the shutter speed without changing anything else. If you change the aperture it will change both the background and the flash exposure so its best to pick the aperture you want for creative reasons and adjust shutter speed and flash power to get the balance between the two elements.

Just as long as you don't go above flash sync speed (usually 1/200 or 1/250) which won't be a problem here as you are probably dealing with really low ss. If you go above flash sync speed you will effect the flash or subject exposure.

Thank you all! Do you think I need to do a rear curtain when flashing too? Or does it not matter?

Jeannine wrote in post #17256320
Thank you all! Do you think I need to do a rear curtain when flashing too? Or does it not matter?

It wont matter in this circumstance. Second curtain is only a factor when you anticipate movement in the subject.

If you can, paste a card to the back of the flash, then bend the flash up to "bounce" it

I might also suggest trying to schedule the shoot at dusk rather than in full darkness. This will render the sky a nice deep blue rather than inky black and will even out the overall exposure of the scene. Google "Gregory Heisler Guiliani" for an example of a portrait with a cityscape background.

Shooting in aperture priority on a Canon will cause the camera to meter for ambient and then flash for fill light on your subject.

You also have to pay attention to the background separation and the subject. Even though your background will be made of lights you still have to be aware that subjects with dark hair can blend into dark parts of the scene. So take care to either pose the subject so that an area of light is directly behind your subject's hair. You can add dimension to the scene by adding a rim light from behind and to the side.

One more consideration is a mismatch in color between the flash and the glow of the city lights. The city lights will have a warm yellow brown glow if you use the flash white balance. If Pittsburgh has gond to LED streetlamps it might be less so. If you do get a yellow tinge you have the option of gelling the flash to match. An orange gel like a 1/2 or 1/4 CTO and a custom WB would whiten up the city lights a bit.

So the event I needed the advice for was a surprise proposal. I was extremely nervous because this is out of the norm for me to shoot night portraits and its such an important moment for the couple. I had recently purchased equipment to do an OCF and this was the first time using it in the field. I practiced the settings the prior night and I am pretty happy with how they turned out.The attached images is not retouched or anything. If I could do it again I would just try to think slower and get all the shots I want, watch the shadows, and maybe make the city a bit brighter. Thank you for all of the advice I had it on the 'cheat sheet' in my pocket in case I totally blanked out!

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You did great, now go out and experiment with a willing model sometime - experience on the location is never a bad thing. In this case, an additional flash behind the couple, and low to be blocked by them may have added some rim light to help his black jacket from fading into the bg. Worth getting someone in a black jacket and playing around till you find the right combo for you.

Yup a slightly longer shutter speed would have lightened the backgound just enough to get the hair to stand out.

ksbal wrote in post #17255942
You will need a tripod and to 'drag the shutter' meaning the flash will fire and freeze your subject, but then the shutter needs to stay open to properly expose the city. Your subject will need to stay still.

So figure out the shot by first figuring out the exposure needed for the city, then adding the model and appropriate flash level for exposure and you got it. You may want to bump the iso a bit so the exposure isn't too long.

looks like the 'dragging the shutter' technique worked