Capturing a natural smile in your photographs can be difficult. All too often people grimace or give a forced smile when asked to smile for the camera. This is a natural reaction when asked to imitate what is normally a spontaneous emotional reaction. Each person's natural smile is slightly different but most have a few common features.
Relaxed Face - Most natural smiles are accompanied by a relaxed face everywhere but the mouth and the very corner of the eyes. A face that has furrowed eyebrows or drawn in cheeks triggers instinctual programming that tells us this is not a happy smile.
Slight Eye Involvement - A natural smile almost always involves a very slight narrowing of the eyes and tiny crinkles at the outside corners of the eyes. This is due to the smile pushing the cheeks up and not due to tension in the eyes. Some people will naturally widen their eyes just a bit to compensate for the reduced visual range from the pushed up cheeks.
Head Movement - Many people will instinctively tilt their heads slightly (either front to back or to the side) when producing a genuine smile. While a slight head tilt can enhance the look of a smile in a photo, be aware of your timing so that you do not wind up with a blurred face due to motion just as you trip the shutter.
Now that you know what to look for in a smile, let's find out how to capture that smile.