It's never a good idea to do portrait photography in bright sunlight.
If you do this, then there will be really harsh shadows on your models's face. Also, because of the bright sunlight, your model will be squinting.
These two things will not give you a very flattering portrait…
So, if you have no option but to do your portrait photography in bright sunlight, then I suggest you follow these sure-fire techniques to improve your photography.
The first thing you need to do is to put the sun behind your model. With the sun behind, there won't be any harsh shadows on the face and the model definitely won't be squinting.
However, putting the sun behind our model will produce an unfortunate effect: to properly expose the model, the background will be overexposed! Just take a look at my photo below. My face is properly exposed and side-lit, but the background is very, very bright.
A solution to this problem is to add a “kicker” light.
The cheapest solution is using a reflector. Just aim the light back to your model and your model's face will be lit. The downside to this is a reflector can also be blinding! And this can make your model squint. Also, you are at the mercy of the ambient light. If the sun, say, gets blocked by clouds, then the amount of light reflected back will diminish.
A better solution is to use an external speedlite. With this, you can control the amount of light that you want to illuminate the model with. Also, you can place the kicker light anywhere you want. The only thing you would have to consider is the power ratio between the sun and your speedlite. And of course, you need to diffuse the speedlite or else it will cause harsh shadows on your model's face.
Also, a positive outcome of putting the sun behind your model is the sun will serve as a rim light. No need to bring, or buy a secondary speedlite just for this purpose. And nothing beats free!
I hope this will help you in your next outdoor photography. And don't listen to those who say you can't shoot in harsh sunlight. You just need to be wise about it. :)
Check out my set up for the photo shoot. I absolutely love the Rogue FlashBender and the Phottix Ares. I also used my Lowepro bag to weigh down my light stand. Also, I believe that it's critical to use a radio transmitter for your off-camera speedlite(s). With the bright sunlight, the infrared used by the camera system might get drowned out by the strong visible light spectrum.
Gear used to make this post: