ND Filters for Long Exposures – Shoot in Manual Mode at ISO 100 on a Sturdy Tripod
The Left Aqua Column is your Standard Non-Filtered Exposure Time.
The Pink Row is your ND Filter Light Reduction in f/stops.
The Table displays your New Shutter Speed with the ND Filter attached.
Shutter Speeds over 30 Seconds (Purple), will require Setting the Camera Shutter Speed to Bulb Mode and Use an Intervalometer.
Example (Shown in Yellow): If you normally shoot at 1/125th of a second (Left Aqua Column) and add a 3 Stop ND8 Filter (Pink Row), your new ND Filter Shutter Speed will be slowed down to 1/15th of a second. Most Digital Cameras can automatically compensate for the addition of ND Filters, and automatically adjust the shutter speed (up to 30 seconds) when you are in Manual Mode.
ND Filters are Essential for shooting Long Exposures and for many Bracketed HDR Shots in Manual Mode at ISO 100 to prevent over exposure. They are used to Smooth Water, Smooth Waterfalls, Long Exposure Fireworks, and Bright HDR Sunsets and Sunrises.
A Circular Polarizer Filter (CPL Filter) is about equivalent to a 2 Stop ND Filter.