Telephoto Prime. With a focal length equivalent to 200mm after sensor-crop factor, the 300mm f/4 is a high-quality prime that reaches out to a very popular telephoto focal length. Its reach makes it great for portraiture and some sports photography. Keep in mind it’s an older design, so don’t expect it to keep up at a NASCAR race.

Autofocus/Manual-Focus Clutch. The 300mm f/4 ED IF uses a clutch design to switch between autofocus and manual focus, giving you fast access to make minute manual focusing tweaks.

Internal Focusing. The internal-focus design means the focusing group is much smaller and easier to move. Not only does this enable the lens barrel to stay in place while focusing, but it also increases focusing speed.