A few tips for beginners on taking portraits in bright sunshine
In San Diego, where I do my digital photography workshops, the sky is often cloudless and the light is correspondingly hard. It helps to use fill flash in these situations. It's surprising how many people I meet who think flash is just for use indoors in dim light, but using your flash and careful subject positioning will save your pictures on bright sunny days.
What is hard light?
Hard light or harsh light is simply light that creates strong shadows and therefore high contrast between the light and dark areas of a photograph. It is caused by the size of the light source in relation to the subject's distance from it. A cloudy day where the sun's light is diffused across the sky, creating a large light source, gives a soft light absent of shadows. On sunny days, the light arrives directly from the sun as a small point in the sky and the shadows are highly defined.
Using fill flash and subject positioning
Portrait photographers tend to avoid harsh midday light, because getting tonal detail is difficult and the subject ends up with really deep shadows around the eyes and nose. Skin blemishes and wrinkles show up badly in hard light. You find yourself mostly trying to make the best out of a bad lighting situation and fill flash can help. Also, keeping the sun behind you helps, especially as the sky looks bluer away from the sun i.e. less washed out.
Dressing your subjects in outfits suitable for the sun can help your portrait. Harsh light washes out lighter colors, but deep blues and reds in clothing can really pop in sunshine and make your photos look rich.
The angle you shoot from can help a portrait in hard light. If you get down low, you can place your subject against a blue sky and that helps the color too. Also, you could try some silhouette shots by placing the subjects head in front of the sun.
Here is an example shot in a recent workshop of another photographer taken against a blue sky. Notice the strong shadows caused by the hard light. Also notice that there is an out-of-focus palm tree behind the subject. Try to avoid having such objects in the background when using this method!
Hats will make the subjects eyes disappear in the strong shadow under the brim. I sometimes use spot metering between the eyes then and just under expose a bit to stop the background blowing.
Too much fill flash can make your subject look kind of plastic against a seemingly artificial background. Skin tones will also get washed out. If you want to soften the shadows a bit without flattening the scene, you can try off camera flash, which is easy to set up if you have a dslr and speedlight. If you use a point-and-shoot camera or a dslr with just a pop-up flash, you don't have this option.
Left: no flash shows deep shadows under eyes and nose. Middle: Using fill flash automatically often washes out the subject's features. With point-and-shoot cameras your only alternative may be to stand further away from your subject (or try to diffuse your flash.) Right: On-camera fill flash turned down a little to help preserve skin tones. These pictures ae just for demonstration - they aren't examples of good portraits!
Sometimes you will see photographers place a small plastic dome over their flash to diffuse the light. This has no effect outside in bright sunlight. All it does is take more power from the flash to create the same effect as without it. Since light is only softened by increasing the size of the source, you need a large flash diffuser or softbox for this to make a difference. Stick to using your small flash dome for indoors bounce flash.
You can experiment with shots into the sun, using your subject to block the sun. The sky will appear white and your subject will be dark. Under expose the picture (your camera probably has a way to adjust the exposure up or down) if you wish to completely darken the face.
Reflectors are useful, but often require an assistant to position them. Plus, on a bright day they virtually blind your subject causing them to squint. Translucent material can be used to soften the light by creating a tent above the subject. You then may need to add flash to prevent the subject being darker then the background.
What to do?
So, let's suppose you are at a San Diego wedding in bright sunlight. What is your best option for getting usable pictures without bringing an army of helpers? If you can't move people into the open shade to take their picture, your best option is to turn on the flash on your point-and-shoot camera and stand about eight to ten feet from your subject. Try to position your subject to minimize the harsh shadows from the sun on the face. With a dslr, I would use my camera in manual mode exposing for the background, but turning down my flash about 1.5 EV. This preserves skin tones while still softening shadows and producing a catch light in the subject's eyes. See this article for using your flash with fast shutter speeds.
I have heard from workshop attendees new to photography that they assumed sunny days were best for portraits. In fact, the best outdoor portrait lighting is close to sunrise and sunset or on overcast days. If you find yourself faced with taking people pictures on sunny days, your first alternative should be to look for some nice open shade where the light is diffused. It will be much more flattering to your subjects.
The picture on the left was shot in woodland where the dappled shade gave a pleasing effect, but the contrast between background and foreground is maintained. The picture on the far left was shot in bright desert sunlight with fill flash.