I always bring a couple of speed-lights on light stands which I use for fill flash.
I struggled for a long time trying to figure out how to take control of light at the beach. The sun is changing quickly, my subjects are backlit, there are reflections. If there’s a harder type of lighting scenario I haven’t encountered it yet. One of the things that helped me the most was learning how to use metering modes properly.
What is Metering?
Metering is how your camera determines what the correct shutter speed and aperture should be, depending on the amount of light that goes into the camera and the sensitivity of the sensor. Back in the old days of photography, cameras were not equipped with a light “meter”, which is a sensor that measures the amount and intensity of light. Photographers had to use hand-held light meters to determine the optimal exposure. Obviously, because the work was shot on film, they could not preview or see the results immediately, which is why they religiously relied on those light meters.
Today, every DSLR has an integrated light meter that automatically measures the reflected light and determines the optimal exposure. You can see the camera meter in action when you shoot in Manual Mode – look inside the viewfinder and you will see bars going left or right, with a zero in the middle. The most common metering modes in digital cameras today are:
Matrix Metering or Evaluative Metering mode is the default metering mode on most DSLRs. It works by dividing the entire frame into multiple “zones”, which are then all analyzed on individual basis for light and dark tones. One of the key factors (in addition to color, distance, subjects, highlights, etc) that affects matrix metering, is where the camera focus point is set to. After reading information from all individual zones, the metering system looks at where you focused within the frame and marks it more important than all other zones. There are many other variables used in the equation, which differ from manufacturer to manufacturer. Nikon, for example, also compares image data to a database of thousands of pictures for exposure calculation. You should use this mode for most of your photography, since it will generally do a pretty good job in determining the correct exposure.
Using the whole frame for determining the correct exposure is not always desirable. What if you are trying to take a headshot of a person with the sun behind? This is where center-weighted metering comes in handy. Center-weighted Metering evaluates the light in the middle of the frame and its surroundings and ignores the corners. Compared to Matrix Metering, Center-weighted Metering does not look at the focus point you select and only evaluates the middle area of the image. Use this mode when you want the camera to prioritize the middle of the frame, which works great for close-up portraits and relatively large subjects that are in the middle of the frame.
Spot Metering only evaluates the light around your focus point and ignores everything else. It evaluates a single zone/cell and calculates exposure based on that single area. If you were taking a picture of a person with the sun behind but they occupied a small part of the frame, it is best to use the spot metering mode instead. When your subjects do not take much of the space, using Matrix or Center-weighted metering modes would most likely result in a silhouette, if the subject was back-lit. Spot metering works great for back-lit subjects like that.
Source: Photography Life