We may earn a commission when you purchase through affiliate links. Learn more.
When shooting long exposures during the day, many DSLR cameras experience light leakage around the viewfinder. These light leaks can cause strange and unwanted effects in your photos as light enters through small spaces around the viewfinder and illuminates the sensor.
These light leaks are small and typically not an issue when shooting photos using very brief exposure times, but when the shutter is left open for several seconds and even minutes at a time during a long exposure, the light leakage can become extremely obvious, ruining your photos. While some cameras don’t seem to have any viewfinder light leaks, it’s not an issue confined only to more inexpensive models — even professional level DSLR cameras often experience light leaks.
Preventing a viewfinder light leak is simple — all you need to do is cover the viewfinder! On many Canon DSLR cameras, the neck strap that comes with the camera actually includes an eyepiece cover on it, designed to cover the viewfinder during long exposures. Other cameras like the Nikon D810 have an eyepiece shutter that allows you to flip a small lever to block the viewfinder and prevent any light from entering. For cameras which don’t offer any easy method to cover the viewfinder, a piece of black gaffer’s or electrical tape will work — if you’re out in the field without tape, often draping a thick shirt over the viewfinder will get the job done too, but you’ll want to make sure the shirt doesn’t catch the breeze and shake your camera.