Where ambient light needs additional lighting

When the lighting is too harsh or limiting it is normal to use some form of continuous lighting, speed-light-reflector-modifier. This is something any good photographer will understand where and how to craft and shape light to create shadow, depth and form to an image.

Real scenarios below with a mixture of ambient and modified lighting.

As the sunsets on Mawgan Porth with the lighting that you see illuminating the bride and groom they stand out subtly. Without the lighting they would be just black figures. Just behind me are all the wedding guests from this beach wedding in Cornwall (plus the crowd of beach onlookers, no pressure there then!)
CREATING DRAMA
With just one off-camera speedlite in a a 31.5″ octobox with CTO gel. See how I have maintained the dark look in the harbour on this wet and cloudy day.
Rather than have the dress pure white the CTO creates the warm look on the bride which also enhances her natural redhead.
Here I am at Mounts Bay Cornwall with this 14 guest wedding including the blind assistance dog. One naked speedlite and one with a 12″ soft-box. I set my second camera up so that one of the guests could document this image for me.
Using the cloud and B&W for drama
Fun with the guests creating the shot

Utilising ambient light only

Here you can see the contrast between the harbour landscape light streaming through the window creating highlights with natural shadow splitting the image diagonally.

Clovelly harbour wedding