If you check any landscape photographer’s bag, I’ll bet you’ll find at least one neutral density (ND) filter. ND Filters are a creative tool for long exposure photography. It’s a secret weapon that allows the camera to capture dreamy cascades of water in broad daylight. This filter is essentially a dark piece of glass in a neutral color which blocks light from entering your lens. Think of ND filters as a pair of sunglasses for your camera. It darkens the scene to allow the shutter to remain open longer. While ND Filters are an essential tool which can elevate images to a new level, it allows light leak to creep into your images at the same time.
When I started the journey of learning photography, I heard the term “light leak” and simply brushed it aside. Since I had not experienced it while shooting, I didn’t read too much about the issue. However, when you’re in the field dealing with light leak, you’ll wish you were prepared to deal the havoc it can wreak on your images.
My first frustrating introduction to light leak was in Iceland of all places. While visiting one of Iceland’s insanely beautiful waterfalls, I knew I wanted a few shots from the water. With that in mind, I donned my fashionable pair of fishing waders and set up my equipment with my selected ND filter. Next, I steadily made my way to the middle of the cold river and firmly planted my tripod for a long exposure shot. Feeling on top of the world, I released the shutter. Click. When the image preview appeared on my viewfinder, I was puzzled and confused. My inexperience and lack of preparedness meant I didn’t know how to stop the light leak right there on the spot. While I missed the shot, the experience motivated me to learn the light leak lesson and avoid any future issue. This post is designed for you to learn to defeat light leak and not to miss your shot!
Light leaks are a common occurrence in long exposure photography. Light leak appears as streaks, banding, or color casts on the image. The stronger the ND filter used, the more susceptible your camera’s sensor becomes to light leak through the viewfinder eyepiece. In addition, light leak can creep into your camera through any ports and doors on the camera body. It can also seek through the gaps between your lens and the filter(s).
While light can seep in from a variety of places during long exposure photography, avoiding light leak is straight-forward. If possible, move your camera and shoot from a shaded spot or wait for clouds to cover the sun. This reduces the amount of light hitting your camera directly.
Cover the Viewfinder Eyepiece Opening
Since changing your location or the weather isn’t always possible, the next step is to block any ambient light from the viewfinder eyepiece. Some camera brands have caps or shutters either attached to the strap or built into the camera body. If your camera does not have this feature, apply a piece of gaffer tape over the eyepiece works. Personally, I prefer gaffer tape over duct tape since it does not leave residue on your equipment.
Cover Any Ports or Doors
If you cover the viewfinder eyepiece and still notice artifacts on your image, try also covering any ports or doors with gaffer tape. For example, if you are using a shutter release cable, light may be getting in through that port.
Cover Any Filter Openings
Another issue could be the area between your filter holder and camera lens. Square filters are simply more prone to light leak because of the distance between the filter and the lens. Truth be told, almost any square filter leaks light when the filters are stacked. First, ensure that your ND filter is in the closest slot to the lens, minimizing the distance between the filter and the lens. The more distance between the filter and the lens risks reflections and light leaking behind the ND filter. Next, cover the top and sides of the filter(s) and holder with gaffer tape, a lens cloth, or a hat. Use anything that you have on-hand to block the light from that area.
Prepare for Battle
Now I always keep some gaffer tape wrapped around the top of my tripod’s leg. The next time I suit up in my waders and walk out into the middle of an icy river, I won’t be losing to light leak or missing the shot. I hope you won’t either.