Using Neutral Density Filters

Shooting Winter scenes isn’t as easy as it looks, especially on a bright, contrasty day. Exposure usually maxes out at around 1/1000 at f/22. Since the exposures are so short a lot of shadow detail gets lost. One way to combat this is using neutral density, or ND filters.

ND filters block light from entering a lens. This makes longer exposures possible in bright, high contrast lighting situations. ND filters come in different graduations, such as 0.3, 0.6 and so on. Each one reduces the light entering a lens by twice the amount.

This is a point of confusion with ND filters, since there are many designations for them. For example, a clear filter, such as a UV zero, reduces light by zero stops. An ND 0.3 filter lets 1/2 of the light pass, so it reduces the light by one stop. An ND 0.6 filter lets 1/4 of the light to pass, so it reduces the light by two stops. This decimal representation is called an Optical Density Number.

ND filters also have “ND 1” numbers. A 0.3 ND filter is ND 101, a 0.6 filter is ND102, and so on.

If you look at the markings on the outside of an ND filter, the designation is almost always given by its optical density number, or ODN. I use this as a guide to correlate the ODN to the number of reduced f-stops.

I made a small ND filter table available as a downloadable PDF. The table is small enough to print out and take with you on shoots. I printed it, cut it out, laminated it and keep it in my camera bag.

ND FILTER TABLE

I was shooting on a cold, clear day this February at a park with a lot of snow on the ground. I shot with my Mamiya 645E using Tri-X at IS0 400. I developed the negatives in Ilfosol 3. Normal exposures tended around 1/1000 shutter speed at f/16 or f/22. Shooting at this speed washes out the highlights and shadow detail, which winds up muddying a black and white negative. Here’ s an example:

BridgeNoFliter

To get more shadow detail I used a 0.6, 0.9 and 2.1 on this shoot.

Here’s a shot using the 0.6 filter. Much better tonal separation and shadow detail.

Bridge306Filter (1 of 1)

Here’s a shot with the 0.9 filter. The 0.9 seemed to work well on this shoot, brining out more subtle shadow detail.

Bridge209Filter (1 of 1)

Here’s a shot with the 1.2 filter, taking the exposure down 4 stops.

Stream12Filter

ND filters help on bright days. It takes the exposure down allowing you to capture more shadow detail. I find them especially useful when capturing Winter scenes.