"When hand-holding a telephoto lens with no VR, you always have to make sure that your shutter speed stays fast enough not to cause camera shake. Always remember that the longer the focal length of the lens, the more prone it is to camera shake.

A general rule of thumb is to keep your shutter speed faster than the focal length of the lens. So if your focal length is 300mm, then your shutter speed should be faster than 1/300 of a second. If you use a DX camera, then don’t forget to multiply the number by 1.5x, which in this case would be around 1/450. Obviously, it all depends on your hand-holding technique.

If you have very strong hands and a good hand-holding technique, you might be able to get great results with much slower shutter speeds, while those with shaky hands might need to increase the shutter speed even more to get acceptably sharp images. I explain all this in detail in my “how to photograph birds” article."