Make Your Handheld Images Sharper
Telephoto lenses are more prone to camera shake with their heavy barrel, and extreme magnification. Even with Image Stabilizers and Vibration Reduction, you’ll want to use the proper long lens technique for consistently sharp photos.
To determine the minimum shutter speed, follow this equation:
Multiply your chosen focal length by the crop factor of your camera. For example 200mm multiplied by a crop factor of 1.6 gives you an effective focal length of 320mm. Therefore, the slowest shutter speed you should hand hold the camera with this setup is 1/320.