Using Neutral Density Filters in a Portrait

bettystudios (29)in #portrait • 8 years ago

Neutral density filters are usually the favorite of landscape photographers, but they can be used in portrait work as well. Primarily, these are used when a soft, out-of-focus background is desired, but the light outside is sunny F22. A neutral density filter allows a photographer to use a wide open aperture of 1.8 with a fast shutter speed; the filter acts to bring the light level down several stops for the desired bokeh (out-of-focus) background.

Photographers using a high-powered studio strobe and high-end Pocket Wizards are not limited by shutter speeds, but for photographers on a budget, a neutral density filter can become indispensable in outdoor portraiture. Most Chinese radio triggers have a max sync speed of 1/250, preventing the use of a wide open aperture in situations with a lot of ambient light.

Here’s a shot of model Jenny Von Rose without the use of a neutral density filter. This photo was taken on a sunny afternoon; we were on a side street where the buildings provided a bit of shade already. A single light set-up was used; a Canon 580ex inside a 28” softbox, triggered wirelessly with inexpensive radio triggers.

The photo is pleasant enough, but the light is flat and boring. Here’s a shot of Jenny done with the neutral density filter on. It’s an inexpensive, graduated ND filter set at the lowest setting, ND2. The lowest setting was used because the light was at around F14, instead of F22.

The same lighting set-up was used, but here you can see that there’s some dimension to the light; the soft box was approximately three feet to the model’s left, which provided a nice fall off, and the model stands out from the background.
Here’s another shot with the ND filter on with the same set-up and same camera settings:

If you are going to increase the density of the filter, you may wish to use manual focus instead of auto focus as the camera will have a hard time focusing with so little light entering the sensor. Manual focus is best used in conjunction with Live View on DSLR cameras as the viewfinder is usually quite dark.
It should be mentioned that not all ND filters are the same quality. The more inexpensive filters are equivalent to placing a piece of plastic over the lens, so you will notice some of loss of sharpness when using a lower-end filter. In addition, some filters will produce a noticeable color cast. Cokin filters are noted for the latter. Genus, Hoya, and Lee are all recommended filters.