using flash outdoors creatively

using gels on your flash

your flash has a “daylight” colour temperature of about 5600K
tungsten lighting has a colour temperature of 3400K
the sun's colour temperature is least red at midday when it is about 5500K, and then by sunset drops to about 3200K
the light from clouds gives a colour temperature of 6500-7500K
the light from blue sky gives a colour temperature of 9000-12,000K, which is why shadows on a sunny are very blue
a full CTO gel (orange) effectively converts your flash to tunsgten colour of 3400K
a 1/2 CTO gel will convert it to 3800K
a 1/4 CTO gel will convert it to 4500K
a 1/8 CTO gel will convert it to 4900K, and is often used by wedding photographers to give the bride's skin a bit of warmth
a 1/2 CTS (straw) gel is often used in preference to CTO for sunset warmth as the skin is said to look better

note: this is NOT going to give you a warm sunset sky, but it will be a touch warmer than in reality thanks to the white balance setting
set exposure to under-expose for the ambient light
set camera white balance to cloudy or shady to create more warmth - esp. in ambient lit areas
place a 1/4 or 1/2 CTO gel on your “sun” flash to warm it up, and set power to over-expose a little
use a flash without gel in an umbrella or soft-box as your subject's main light - this will provide warm skin tones
to get even more creative, you can use:
- a flash fired through a large umbrella or softbox using a 1/4 CTO gel to mimic the diffuse warm light of the sky around the sun
- and a 2nd flash in FRONT of, and perhaps below the umbrella with a 1/2-3/4 CTO gel and flash set at lower power to mimic the actual setting sun

this is called key shifting
set camera white balance to tungsten (this makes the sky and all ambient lit areas blue)
place a full CTO gel on your flash(es) to light your subject and have normal skin tones

step 1. the whole reason for shooting at sunset is usually the warm lighting, so step 1 is to take control of your camera's white balance, and consider setting it to around 4000-4500K depending upon how warm you want it
step 2. set camera to shoot in RAW mode so you can more readily fine tune your white balance later
step 3. consider setting your camera to manual exposure so you can control how dark you want the skies - they usually look best and more saturated if under-exposed a touch
step 4. set aperture to around f/8 on a full frame camera so that you have sufficient depth of field (DOF) to keep the clouds reasonably sharp
step 5. decide on the type of image you want

this is the easiest - just under-expose the sky and your subject will appear almost black depending on how bright the sun is still or it it is above the horizon or not.
no flash!

using the sun or the glow from the sunset to sidelight your subject while still allowing you to hopefully get some nice skies in the background
the subject's shadow areas may be too contrasty, these can be assisted by either:
- use of a reflector, or,
- a fill in flash, perhaps with a 1/4 or 1/2 CTO to help match the main light from the sunset

to get a lovely, under-exposed sky, you will need to under-expose the sky and thus your subject, which then will require you to use a flash as a main light for your subject
the flash should preferably be in a soft box or umbrella to provide a nice, diffuse unobtrusive light, and should have a gel to match your desired white balance setting