It must be spring, because I’m thinking of waterfalls photography and how to create that silky, soft look with water. If you’ve been following my photography, you know that many of my photos use that effect to even out the surface of Lake Superior or the ocean to carry the sky’s color throughout the scene. Recently, I upgraded my filter system to Singh-Ray’s Mor-Slo filters and want to write up a primer on how to use Singh-Ray’s Mor-Slo filters to create long exposures — I get asked this during my Lake Superior photography workshops and wanted to write something for folks that can’t make it to my workshops. Last year, I wrote about how to use vari-nd filters for waterfall photography, so this year, I decided to write about how to use solid neutral density filters to do something similar.

Create Long Exposures with Singh-Ray’s Mor-Slo Filters

Singh-Ray’s Mor-Slo filters currently come in three different intensities: 5-stops, 10-stops and 15-stops. The more stops that the filter has, the darker it is, which means that you can create a longer exposure. Each stop that the filter has doubles the length of exposure from the last stop. So, a 5-stop filter would double the exposure five times. I have both the 5-stop and the 10-stop. The longer exposures blur action, so the surface of the big lake or ocean looks like fog (see the header image).

I find that during the sunrise and sunset, because the light conditions change so quickly, the 5-stop seems to work better for me. With a 5-stop, I can keep my exposures around 30 seconds to 1 minute. With a 10-stop at sunrise and sunset, I find that exposures are often as long as 8 minutes. The light changes significantly during that time frame, so I’ve found that you just don’t get the best color during sunrise and sunset with an 8 minute exposure. For something that long, the color needs to stay constant if you want to capture it.

Click the following images to see them larger for examples of a shot with the filter and one without the filter. The shot without it is 1/30 of a second long the shot with the 10-stop Mor-Slo filter is 30 seconds long.

To use Singh-Ray’s Mor-Slo filters to create long exposures just follow these steps (Note: this works with any ND filters):

1. Put your filter holder on your lens.
2. Compose and focus.
3. Turn off your focus system (see How to Use Rear Button Focus for a better autofocus setup on your camera).
4. Switch to manual mode.
5. Set your aperture based on the depth-of-field you need. For landscape photography, usually around f/11 to f/16.
6. Adjust your shutter speed to center the exposure scale.
7. Shoot a test shot and adjust your exposure as needed.
8. Insert your Mor-Slo filter or other ND filter into the holder. Make sure that it’s in the closest slot to the lens.
9. Adjust your shutter speed based on the number of stops. See below for the ways to do this.
10. Take the picture.

Adjusting the Shutter Speed for ND Filters

You can adjust your shutter speed several ways to account for the density of Mor-Slo filters. The first involves math. You simply double the length of the shutter for each stop. For example, if you’re using a 5-stop Mor-Slo and you start with an exposure of 1 second before you put the filter on, you end with an exposure of 30 seconds.

• 1st stop: 1 second x2=2 seconds
• 2nd stop: 2 seconds x2=4 seconds
• 3rd stop: 4 seconds x2=8 seconds
• 4th stop: 8 seconds x2=15 seconds (note that in camera stops the next step is 15 and not 16)
• 5th stop: 15 seconds x2=30 seconds

The second way is you download an app to do the calculations for you. Usually, you have to select your shutter speed without the ND filter and then select the intensity of the filter and it will tell you how long you need to set your exposure.

There’s also this handy chart that I made for you. To use the chart, you find your shutter speed without the filter in the left column and then follow the row to your filter and it will show you the exposure. This way is one of the easiest ways. You can download a pdf of the chart formatted to fit on a 4×6 inch index card.

• Download: ND Filter Exposure Chart [pdf] — A filter chart that shows the required shutters speeds when you add a 5-stop, 6-stop or 10-stop Mor-Slo filter or the Lee Little or Big Stoppers.

The way that I like to do it is by just counting the number of turns on my shutter speed dial. I have my camera set up to adjust my shutter speed by 1/3rds, so three turns of the dial equals a change of one stop. You can find out how you have your’s set up by checking your menu items or by setting your camera on manual and setting your shutter to 1 second. Turn it to 2 seconds and count the number of clicks it takes to get there. If it’s three, then you have it set up for 1/3rd. If it’s two, then you have it set up for 1/2th. For thirds, multiple 3 by the number of stops to get the number of clicks you need to turn it. For 1/2, multiple 2 by the number of stops to get the number of clicks you need to turn it.

• 5-stop: 1/3 = 15 clicks; 1/2 = 10 clicks
• 6-stop: 1/3 = 18 clicks; 1/2 = 12 clicks
• 10-stop: 1/3 = 30 clicks; 1/2 = 20 clicks

You can also count it off by stops. For example, 1-2-3 turns = 1 stop, 1-2-3 turns = 2 stops, etc…

But if you’re just learning, it’s nice to have a chart to check in the field, because they you can concentrate on the photography and not the math.