In some shooting environments, flash photography is strictly prohibited. Often, the ambient light is so poor that the shutter speed becomes very low. In this situation, the photo can be easily affected by blurs caused by camera shakes and subject movement.
If you are handholding a lens, the rule of thumb says you typically need 1/f (f is the focal length in millimeter) second of shutter speed. For example, if you are shooting with a 200mm lens handheld, you need about 1/200s or faster shutter speed to avoid most of the camera shake. This is for average people. Some one may have very steady hands, others may have especially shaky ones. If you have a lens with vibration reduction (VR), image stabilization (IS), or vibration cancellation (VC) functions, the speed requirement can be greatly relaxed. Often, you can shoot with up to 4 stops (or 16 times) slower shutter speed.
Another obvious option is to use a monopod or tripod if possible. Correct shutter release technique helps too. Avoid poking the shutter release button. Try to place the finger flat on the shutter release button and gently roll the finger from front to back to release the shutter.
The above tips are for avoiding camera shakes. Subject movement can also cause blur in the photo. The shutter speed needed to freeze movement depends on many factors, such as how fast the subject is moving, the distance between camera and subject, the focal length, etc. 1/500s is likely ok for human subject playing sports, but 1/5000s or even 1/20000s may be needed to freeze the hummingbird wings. 1/15s may be OK for people standing still.
In some cases, blur in photo is intentionally introduced to create sense of motion. However blur is not suitable for all photography situations. So, what can be done?
For properly exposed photos free of unwanted blurs, you need to achieve sufficient shutter speed. To do that, you can
- Use a fast lens. A lens is fast if it has large maximum apertures. This typically means lens with aperture at least f/2.8, and preferably larger, such as f/1.8 or f/1.4. Lenses become more expensive as the maximum aperture increases, especially for the ones with long focal lengths. Fortunately, 50mm or 85mm lenses with maximum aperture of f/1.8 can be bought for reasonable prices. Opening up the aperture also reduces the depth of field (DOF), which will reduce the margin of error for focus.
- Use a lens with vibration reduction (VR), image stabilization (IS), or vibration cancellation (VC) functions. This type of lens will greatly reduce blurs caused by camera shakes but will do little to freeze subject movement. For the latter, you need to have sufficient shutter speed, which you can achieve with fast lens and increased ISO. Alternatively, you can turn-on the built-in vibration reduction function if your camera has it.
- Increase the sensitivity (ISO) of the camera. The trade-off is noise. When it comes down to a blurry photo or a photo with a lot of noise, you’ll have to make your choice.
- Shoot more frames. Sometimes in a series of shots, you could find one frame that is mostly free of blurs. This helps when you really cannot get the shutter speed you need.
Using a flash can greatly enhance the quality of the pictures you take in dim light conditions. Even though I found the above tips helpful for myself, I would still prefer to use flash if possible, especially for parties and ceremonies. For concerts or shows with stage lighting, flash photography does not really help because if washes out the colors from the stage lights and removes the mood of the environment.
Keywords: Available Light Photography, Photography tips