How Low Can You Go?
Hand holding by moonlight. No, not your sweetie. Your camera. The question here is how low is the light level where you can reasonably hand-hold the camera without serious risk of shake. The common answer is to use a tripod at any shutter speed slower than the reciprocal of the lens focal length—one 50th second at 50mm, one 100th second at 100mm and so on. But this is only a general guideline and not a hard rule. Some photographers insist on always using a tripod while others claim to be able to hand hold with a wide angle lens for nearly a second.
The Exposure Triangle
The three settings of shutter speed, aperture, and ISO determine proper exposure. In low light, the common approach is to open the aperture, increase the ISO or both in order to reduce the shutter speed to a level that can reasonably be hand held. This usually works, but at a cost. Opening the aperture reduces depth of field and may not be the sharpest setting for a particular lens. Increasing the ISO puts grain or noise in the photo and reduces image quality.
Test Low Light Hand Held Capability
So what about hand holding in moonlight? Even a fully open fast lens and ISO in the stratosphere (or the camera’s maximum setting) will not permit a hand held portrait by the light of the silvery moon. Hand-held night photography is possible in cities with lots of light sources. But even here it is necessary to open the lens and raise the ISO significantly. To test this in a low light situation, set the camera to manual or aperture priority, open the lens wide and raise the ISO until the shutter speed is fast enough to hand hold. Take a few shots at this setting and check that grain is acceptable and there is no shake. It is best to see this on the computer screen rather than the camera monitor.
Hand Holding Doesn’t Always Work
You may discover that always hand holding the camera for low light photography is impractical and marginal at best. This photo was shot for 1.3 seconds at the maximum f3.5 and ISO 1600. Lighting is a street lamp and full moon. The shutter was open way too long to hand hold so camera shake is obvious. Grain is also more than it should be. This is a low light situation where camera stabilization is essential. Low light capability varies among cameras. Test to see what light conditions and combination of ISO, aperture and shutter speed gives you acceptable hand held performance.
Camera Stabilization Is Essential
Even if hand holding is possible in some low light conditions, it is always best to use a camera support. It allows a lower ISO to minimize grain and a smaller aperture for better depth of field. In addition, camera stabilization allows long exposure effects that would be impossible to hand hold—traffic trails for example. Time lapse video and low light HDR also require camera stabilization. Even landscapes by moonlight become possible. In low light get the camera out of your hand and onto a solid support. The best solution is a sturdy tripod, but a pocket size alternative like HandlePod will do the job without the weight and bulk.