Shooting outside is great for realism, but the sun can present problems, especially as Rich noted, on figures with large areas of fleshtones or light colours. there's a couple of things you can do. Firstly, sometimes it helps if you can turn your subjects around a little so that the sun is lighting the shot from a different angle rather than full-on. This can also give you nice dramatic shadows across faces, etc. If that doesn't work, you could try moving your shot to a shaded area, where you'll still get a nice outside shot minus the glare. Failing that, just wait for an overcast day. I love shooting on overcast days, you get a really smooth, even light which can make for some awesome looking shots. Hope that helps!

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"The future's uncertain and the end is always near." - The Doors "Roadhouse Blues".