my personal observation

[ReneR]

Daylight in a portrait
I don't know whether you aware of this tip or not, anyway, I'll state it one more time. Hope it will be useful somehow.

Shooting outdoor always bear in mind that bright sunlight can often prevent you from getting a natural facial expression in the photo. Lights might fall into the eyes and as a result, the model begins to squint and all this looks unnatural.

To avoid this, place the sun behind so that the light will not fall on the face but instead will fall on the back of the head and shoulders. So in this way, you'll get rid of the problem, and also get a nice illuminated halo around the shoulders and head. Though if the face turns too dark, then use a flash or reflector.

 

[KmH]

With the sun behind the subject, just be sure your subject isn't underexposed.
If your subject isn't underexposed then the background or large parts of the background is usually blown out/clipped (pure white/no detail).

To make sure the subject of the portrait is the brightest thing in the image or has the most visual weight use flash to illuminate the subject and balance the flash and camera settings to balance the flash/background exposure. The technique is also known as dragging the shutter.

 

[ReneR]

thanks for adding

 

[chuasam]

shoot in open shade

 

[Breezy85]

shoot in open shade

This. But also you don't want the sunlight in your own eyes as well. I would recommend spots where you're in the open shade, the sun is not in the model's eyes or your own. Personally I prefer to shoot where there's at least some cloud cover so watching the sun can be avoided.

 

[TCampbell]

You can massively improve the quality of outdoor shots by using a decent flash. By "decent" ... it needs to have adequate power for the shot (the pop-up flash built into many cameras is fairly limited).

This massively improves the situation where a bright sun creates such strong highlight areas that the shadows are much too dark.... by filling in the shadows.

There's a concept called "flash contribution" (basically what percentage of light came from the flash vs. ambient sources such as the sun). I typically set the flash-exposure compensation (FEC) to about -1 ... that means I want the flash to be under-powered by 1 stop (or about 50% power) relative to the Sun. This creates an exposure where roughly 2/3rds of the light comes from the sun and 1/3 comes from the flash. But you really should play with your FEC to determine what works best in your situation.

(Just don't forget that you changed the FEC and remember to change it back when you're done... or you'll be scratching your head the next time you need to use the flash when it wont give you the light that you want.)

 

[smoke665]

@TCampbell, as always useful information, but what of those like myself that don't use TTL? Derrel put me onto a really great video by Dean Collins and Chormozones I've used this in studio, and found it to be quite accurate. I haven't put it to the test outside yet, but I suspect the same method or slight variation of would work outside with a flash equally well.