Neutral Density Filters and Exposure Times at Sea

Neutral Density Filters and Exposure Times at Sea

A neutral density filter allow long exposure times, even when there is a lot of light. It flattens water surfaces when the exposure is long enough. But don’t use it at sea just because you have one. Use it only when necessary.

A sea is a dynamic place. The vast water surface is always in motion. At the shore, the waves turn into a surf. Especially with rocky shores, the surf can be quite impressive. The force of the sea shapes the shoreline, moving rocks and forming dunes that protect the land from the raging waters.

Sandy beaches are nice, but the beaches with rocks and stones offer even more impressive moments to capture. That is why I chose a Lee Big Stopper a long time ago. It allowed me to shoot longer exposure times at sea. But it had one downside I never thought of when purchasing the filter. The impressive force of the water wouldn’t be visible anymore.

The flow of the water captured by using a ten-stop ND filter.  The large water speed together with the strong winds prevented a flat water surface during the long exposure time.

Think Twice About Using Strong ND Filters

During my workshops, a lot of participants grab their ten-stop filter the moment they arrive at the sea. Although the filter can give great results, it is wise to think first about the effect you want to achieve. Do you want to see the movement of the sea or do you prefer a flat water surface without any movement at all?

Today, I use the Haida M10 filter system with Red Diamond filters.

A lot of photographers seem to think about two sorts of images: the short exposure with frozen water movement, where every drop of water is visible in the image, or the long exposure, where there is no movement visible at all. In a way, it’s like a zoom lens is used by many. Just like all the focal lengths between the two ends, there is also a whole range of exposure times between frozen water and a flattened water surface.

Choosing the best exposure time is perhaps the most important thing at sea. How do you want the water to appear in the frame? It not only depends on your wishes but also the circumstances. Is there a lot of movement going on or not? Are there rocks or is it a sandy beach? Is the tide coming in or going out? How is the wind influencing the water?

Shooting at Etretat in France. For this image, I preferred a longer exposure time to flatten the water surface.

Movement or Not?

First of all, don’t think a ten-stop filter will show the movement of the water. It will give a flat water surface without any detail, eradicating every evidence of movement. 

On the other hand, a very short exposure time will show the waves crashing onto the beach or against rocks. It will freeze any motion and in a way, it also stops the movement. You will be able to make impressive images, but you won’t show the motion of the water itself. 

Just look at the difference between a long exposure and a shorter exposure in the before-after image below. Which one do you prefer?

To show the movement of the water, it is best to choose an exposure time that isn't too long or too short. A shorter exposure time will freeze the water movement too much. A longer exposure time will eradicate the movement. The best results are often found between 1/8 second and 2 seconds.

I used a 1/4 s exposure to show the movement of the incoming tide. This could not be captured with a ten-stop filter.

If you have a lot of experience, it is possible to determine the best possible exposure time just by looking at the situation and the water movement. But if you’re not that experienced, it is always good to start with an exposure time of one second. Make a few test shots and work your way from that starting point to the best possible exposure time. It may take a couple of tries and it may vary depending on the force of the waves, but you will get a good indication of what works best.

Water movement with 1.6 s exposure

Water movement with 4 s exposure

Water movement with 13 s exposure

Water movement with 120 s exposure

Incoming and Outgoing Water

Depending on the tide, there is a big difference in the speed of the water. During incoming tide, the water will flow much faster and more wildly compared to the outgoing tide. But the direction of the water makes a lot of difference as well. Incoming water has a larger speed compared to outgoing water. Just look at it for a while before setting up your equipment. See how the speed is and the best movement to photograph.

Incoming tide can give a large water speed. This is with a 4 s exposure time.

Between incoming water and outgoing water, there is a moment where the water is at rest. This image had a 2.5 s exposure time.

When the water is flowing back, it will be much slower. This image has a 2 s exposure time.

Using Filters Can Make the Exposure Time Way Too Long

Don’t grab your ten-stop filter too soon when you are at sea, but try to find out which exposure time you need for the wanted result. Chances are you won’t need the filter at all. Or perhaps you need a three-stops filter instead of ten-stop.

This is the reason why I always advise photographers to buy not only the popular ten-stop filter but also six-stop and three-stop. If you’re using a polarization filter, it will work as a one-stop ND filter also. This way you have all the necessary ND filters to get the right exposure time. Today I use the Haida M10 filter system for that, together with the excellent Haida Red Diamond filters.

When Is a Ten-Stop ND Filter a Good Choice?

Up until now, I was talking about the surf. But if you love shooting the large water surface of the sea itself, a long exposure time may give you a great effect. Just imagine, the waves and the force of the water are only visible when they hit land. The water surface itself is tranquil to the eye, and a ten-stop filter will exaggerate this.

Using a Fast Shutter Speed at Sea

I can think of only one situation when a fast shutter speed is the best choice at sea. This is when large waves are crushing into the shoreline or onto rocks, especially during storms. It allows you to capture the enormous force of the sea, frozen by a short exposure time. But then again, perhaps a longer exposure time can also turn out quite nicely.

The spray of water and the waves crushing onto the rocks are best captured with a short exposure time. This is 1/400 s.

If you’re a photographer that also loves to take photos at sea, how do you prefer to capture the water? Do you use strong ND filters to flatten the water or do you prefer to show the movement of the water? Please share your thoughts in the comments below.

Nando Harmsen's picture

Nando Harmsen is a Dutch photographer that is specialized in wedding and landscape photography. With his roots in the analog photo age he gained an extensive knowledge about photography techniques and equipment, and shares this through his personal blog and many workshops.

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Great article and examples! (And thanks for writing an actual article and not making a video!)