22 Jun 2011

Exercise: Contrast and shadow fill

Adding more lighting elements, this exercise asks us to examine the effect of reflected light.  The set up asks for a simple subject initially lit by a straight forward lamp put at right angles to the camera line of sight.
The result looks like this:

 Simple lamp
I deliberately turned the figure away from the slight source so that we could easily register the changes to the shadowed area as the reflectors are brought into play.  We can see that there is no diffuser on the lamp as the shadows are hard edged and there is no spill over of light.  This is going to the the photograph that shows the greatest contrast of this set.

From this point on the images are taken using a soft box and a reflector, apart from the first one which uses the soft box alone.  The set-up looks like this:

With the softbox illuminating the figure there is less contrast and the shadow edges are less obvious.  Of interest, the background is now receiving light which spills over from the softbox giving the figure greater contrast from the background.  This shouldn't be confused with the lesser contrast that the lighting gives the figure alone.

The first photograph with a reflector has it positioned opposite the softbox at a distance of 1 metre.

White reflector at 1 mtr

With the addition of the reflector a small amount of detail becomes obvious within the shadowed areas.  It is, perhaps, easiest to see around the base where previously the black rim blended with the black surface underneath it.  Now the two can be identified as separate areas.  The detailing around the middle of the figure is also starting to be apparent.

White reflector at 1/2 mtr

Since light obeys the Inverse Square Law, halving the distance of the reflector to the model will increase the light it produces by a factor of 4.  The effect on the dark areas of the subject is obvious with considerably more detail colour apparent.

Flat dull silver reflector

The white reflector has now been replaced with dull metal foil which, although not as reflective as shiny foil is still one step more efficient at returning the light than the plain white reflector.

Flat shiny silver reflector

With the foil turned to the shiny side yet more light is given to the shadowed areas of the figure but it isn't quite as easy to register as the other steps have been.  Try viewing the expanded view of the image by clicking on it to see the increase in detail that can now be seen.

Crumpled shiny silver reflector

The final part of the exercise required us to crumple the silver reflector so that it looked like this.

The effect this has is to reflect the incoming light from the softbox at many random angles, effectively diffusing it but not reducing its intensity by as much as a semi transparent diffuser membrane would do.  So we see that some corners of the figure that hadn't previously received light have now been revealed.

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