How to: flash and burn

[jdepould]

Sometimes, you have really great ambient light, but you want to be able to control the light falling on your subject. By default, your camera will simply expose for the flash, and ignore the ambient. This can lead to a properly exposed person floating in a black hole. To avoid this, you need to flip your camera to M and engage your brain.


5" at f/13 and ISO200

The key thing to remember is that shutter speed controls your ambient exposure, and aperture controls your flash exposure. Adjusting ISO affects everything, so it's best to leave that alone.

First, you have to think about how you're going to light your subject. Most people will probably use a speedlight. If your speedlight has TTL, this reduces the amount of thinking you need to do.

Most cameras default to a shutter speed of 1/60s for flash exposures. In a lot of cases, this is too fast for a good, low ISO ambient exposure.

Set your ISO to 100 or 200.

Then pick your aperture, since aperture is one of the ways to control your flash exposure. I like anywhere from f/8 to f/16.

After you set your aperture, balance your in-camera light meter as if you aren't using a flash. This means adjusting your shutter speed.

The flash will freeze your motion, but if you really really need a faster shutter speed, bump the ISO, and pick a smaller aperture or reduce the power on your flash.

If you're outdoors or using daylight for ambient, you're ready to shoot.

This process leads you to 2" at f/16 and ISO200, and a picture that looks something like this:


If your ambient is artificial light (tungsten/incandescent or fluorescent), then you need to gel your flash to match. Or you can gel your flash to mis-match for fun effects.

Tungsten gel against daylight ambient:


You can make your own gels from a sample kit, or buy them (I have the Nikon SJ-1 set).

Sometimes, you're really in the dark, so you need to increase your ISO.
Trial-and-error comes into play here:
3" at f/8 and ISO800, flash at -3.0EV


One last thing to consider is when you want your flash to fire. The default is usually a first curtain sync, which means the flash fires at the beginning of the exposure. I prefer second curtain (or rear) sync, because motion during the exposure looks more natural.

[candleman]

wow, i'm really surprised.. 3" !
did you get them to stand still or did they walk away after the flash? i'd be worried about the background slightly showig up or getting faint ghosting, particularly if they already have a fairly strong natural light. (IE fixed lighting at the event/location)

i wasnt expecting the flash to freeze them in the frame THAT much.

great post, thanks.
i reckon this deserved to be doubled up in the tutorials section.

[jdepould]

Originally Posted by candleman

wow, i'm really surprised.. 3" !
did you get them to stand still or did they walk away after the flash? i'd be worried about the background slightly showig up or getting faint ghosting, particularly if they already have a fairly strong natural light. (IE fixed lighting at the event/location)

i wasnt expecting the flash to freeze them in the frame THAT much.

great post, thanks.
i reckon this deserved to be doubled up in the tutorials section.

He was standing there the whole time. Small amounts of motion aren't usually visible, and the flash was at the end of the exposure. It's all about the balance. If you have stronger ambient, you can use a faster shutter speed.

I thought about putting this in the tutorials, but it's a lighting thing. Meh.

[candleman]

Originally Posted by jdepould

the flash was at the end of the exposure. .

aaah. i see, sneaky.
i'll lock that in my memory banks for the day i finally get my off-camera friend.
thanks again. its helped.

[PhotoNewt]

One added advantage of using second curtain flash is that people usually stay still for a photo until the flash fires; the flash being fired at the end of the exposure can reduce subject motion some more.

Very good post, short and informative.

[RussHeath]

Good explanation of the topic and excellent examples, Jamie. I particularly love the last shot with the waterfall in the background.

[jdepould]

Originally Posted by RussHeath

Good explanation of the topic and excellent examples, Jamie. I particularly love the last shot with the waterfall in the background.

We had a great time, and screwing around with the fisheye was especially fun. Niagara Falls in winter isn't for the faint of heart though, that's for sure.

[shutterbug_wannabe]

Jamie, Help me understand first curtain, second curtain flash sync. How do I achieve this? I use a D90. This is something I would love to play with and never have. I have seen such wonderful and creative images using these techniques, but haven't wrapped my mind around it (there's not alot there to wrap either so be gentle!) Thanks

[ni2sml]

Great explanation and examples!

[jsanders]

Great article. Which colour filters did you use in 2 and 3?