A 10-stop neutral density (ND) filter can transform moving water into a silky blur, smooth out ocean waves, or turn passing clouds into dramatic streaks. But there’s one frustrating problem: your camera may struggle to focus once the filter is attached.
That’s because a 10-stop ND filter reduces the light entering your lens by approximately 99.9%. Even in daylight, your camera’s autofocus system may struggle to see enough detail to lock onto a subject.
Fortunately, there’s a simple technique that makes focusing with strong ND filters much more reliable.
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The Secret: Focus Before Attaching the Filter
The most dependable approach is to establish focus before the ND filter blocks the light.
Here’s the process:
- Compose your shot without the ND filter. Mount your camera on a tripod and frame the scene exactly how you want it.
- Focus on your subject. Use autofocus or magnified live view to focus precisely on the important part of your composition.
- Switch to manual focus. Once focus is confirmed, switch your lens or camera to manual focus so the camera won’t attempt to refocus.
- Attach your 10-stop ND filter. Carefully screw on or slide in the filter without touching the focusing ring.
- Calculate your new shutter speed. A 10-stop filter requires approximately 1,024 times the original exposure time.
- Take the photograph. Use a remote shutter release or self-timer to minimize camera movement.
For example, if your correct shutter speed without the filter is 1/125 second, adding a 10-stop ND filter increases the exposure to approximately 8 seconds.
What About Back-Button Focus?
If you use back-button autofocus, you already have an advantage. Once you’ve focused using the AF-ON button, you can release it and take the photograph without triggering autofocus again, provided your camera is configured to separate focusing from the shutter button.
This eliminates the need to switch between autofocus and manual focus for every exposure.
However, be careful not to accidentally press AF-ON after attaching the filter.
Can You Focus Through a 10-Stop ND Filter?
Sometimes! Modern mirrorless cameras with sensitive autofocus systems can occasionally focus through strong ND filters, particularly in bright conditions.
But reliability depends on the camera, lens, available light, and contrast in the scene.
If autofocus begins hunting back and forth, don’t waste time fighting it. Remove the filter, establish focus, and reattach it.
A useful trick: If you’re using manual focus, magnify your camera’s live view display to 5x or 10x before attaching the filter. This makes it easier to confirm sharpness on distant buildings, rocks, or other stationary subjects.

Photo captured with a 10 stop ND filter and a 30 second shutter by Benjamin R.
Don’t Make This Common Mistake
One of the easiest ways to ruin a long exposure is to accidentally change focus while installing the ND filter.
This is especially common with screw-on filters because twisting the filter can also move the lens’s focusing ring.
After attaching the filter, check that the focus ring hasn’t shifted. On some mirrorless cameras, you can also verify the focus distance using the camera’s distance scale.
For lenses with electronic focus-by-wire systems, remember that switching the camera off or changing certain settings may reset the focus position.
Bonus Tip: Focus Stacking Isn’t Always Necessary
Landscape photographers sometimes assume they need to focus at infinity for every long exposure. But that isn’t always the best choice.
If your composition includes foreground rocks, a waterfall, or other nearby elements, focusing at infinity may leave those details soft.
Instead, choose an appropriate focus distance and aperture to achieve the depth of field you need. For many landscapes, f/8 or f/11 is a useful starting point, although the ideal setting depends on your lens and composition.
If both very close foreground objects and distant scenery must be perfectly sharp, focus stacking can help—but moving water and clouds may complicate blending the exposures.
Final Thoughts
A 10-stop ND filter doesn’t have to make focusing difficult. The key is to focus first, lock your focus, and attach the filter afterward.
This simple habit can save you from discovering that a carefully composed 60-second exposure is completely out of focus.
And when you’re working with long exposures, getting the focus right before pressing the shutter can save a surprising amount of time.
Pro tip: Before beginning a series of long exposures, take one quick test shot without the ND filter and zoom in to confirm sharpness. It’s much better to discover a focusing mistake in a fraction of a second than after waiting several minutes for an exposure.
Want to Master Long Exposure Photography?
Nailing focus is only part of the process. Our new Long Exposure Photography Guide & Cheat Sheets (currently 70% off today for our
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You’ll also learn how to avoid common mistakes and edit your long exposure photographs for professional-looking results.
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