Posted by Garry Tyler on June 01, 2015
Using just a single light source with a lot of direction can often produce a very harsh and direct light, bleaching out your highlights and creating very dark hard contrasting shadows. This leaves us with an undesirable finish in portrait.
This has two effects on the original direct light, firstly with it being broken down into smaller sections the light will become more directional, this is caused by the light having to pass though each section of the grid and when used with the right modifier at the correct distance can help to create a natural vignette on your backdrop, as seen in the image to the right. The second effect that a grid has when used on a direct light source is to soften down that harsh contrast created by having a single light source. This happens due to some areas of the light being flagged out on different areas of the subject by the gridded sections. In this example, we simply used a single light with a 1x1- 40° tight grid to create a very tight light source.
Due to the working space in the studio, creating the image on the left, I had to have my rim lights very close to the model to get the desired effect. I then had the problem of get the angle I wanted to get the light falling onto the edges of the face, along with stopping the lights from creating a little lens flare, again I used grids on each of my backlights with them facing almost across the lens, this allowed me to get the correct light where I wanted it, but also that 2x2 - 30° kill to the light stopped it going where I didn't want it, this then coupled with a beautydish at a very low power to put a little tone back into the face and eyes, up high over the models head. Wanting to bounce a little bit of light back up under the chin this was then done by removing the grid from the beauty dish to allow for some fall off to hit and bounce from reflector under the chin.
When taking control of that light source, grids allows for many uses and with the massive range of grids available for a massive range of lighting modifiers and softboxes to beauty dishes and standard or deepdish reflectors, changing the aperture of the grid along with the depth of the grid allows us as the photographer to control the light source as we require.