These three pictures were made from through focus stacks consisting of 18 frames using the 'Do Weighted Average' macro. They are of the tip of the abdomen of a small midge, using transmitted light. The Logitech webcam used was set to three different exposure times, 1/100th, 1/50th and 1/30th of a second.
Notice that none of the pictures shows all of the detail, the dark picture shows the outlying detail but not much in the darker areas, the lightest picture looses the bristles and some detail in other light areas. Even the middle picture cannot show the bristles in full. This happens because the camera can only detect a limited range of brightnesses, less than the range of the human eye. One solution is to combine all three pictures so the result contains more detail, the drawback is that the 256 values of the 3 basic colour components of each pixel define the range of colours available which is constant in the initial pictures and the result so that to produce the result there is bound to be some loss in colour depth. I beleive some commertial programs get round this by adjusting the colours on a local basis, but this can lead to halos around some areas.
The picture above was produced by stacking using an experemental function in CombineZM. It uses a weighted average techniqui followed by reassignment of the colour values, all calculated at greater accuracy than the 0-255 colour value steps, and finally adjusted to fit these values.