* @return Returns the shutter speed as a {@link Rational} value.
*/
public static Rational convertShutterSpeedFromAPEX( int apex ) {
final double n = Math.exp( - convertAPEXToEV( apex ) * LN_2 );
return n > 0 && n < 1 ?
new Rational( 1, (int)fixShutterSpeed( 1/n ) ) :
//new Rational( 1, (int)(1/n + 0.5) ) :
new Rational( (int)(n * 10), 10 );
}