For years, as a general rule of thumb, photographers have been taught to select a shutter speed that is no slower than 1 divided by the focal length of the lens. For example, when shooting with a 500mm lens, the shutter speed should be no slower than 1/500th of a second (1 divided by the 500mm focal length). Using a fast enough shutter speed helps minimize the risk of blur resulting from camera movement. The chances of camera movement blur becoming evident in the photograph increase as the lens offers more magnification (as in the case of telephoto lenses with higher focal lengths).

On the other hand, photographers often strive to select a slower shutter speed for certain subjects. A slower shutter speed provides the photographer with an opportunity to lower the ISO setting--which in turn tends to maximize image quality. A slower shutter speed can also give the photographer more flexibility with the aperture setting--which in turn opens up more options for controlling the depth of field for sharpness with the frame.

Yesterday, I tested some limits of how slow I could set the shutter speed while still creating tack sharp images. Keep in mind, if I simply held the camera and fired off frames, a shutter speed of 1/500th would be the guideline. This first image was captured at 1/80th of a second:

Rope gripClose up of the hand and foot of a female gorilla gripping a rope inside the Tropic World exhibit at the Brookfield Zoo in Brookfield, Illinois on February 19, 2014 The next two photographs were captured using a 1/40th of a second shutter speed:

Red-tailed monkeyThe red-tailed monkey (Cercopithecus ascanius) at the Tropic World exhibit at the Brookfield Zoo in Brookfield, Illinois on February 19, 2014 Baby gorillaBaby female gorilla in her mother's arms inside the Tropic World exhibit at the Brookfield Zoo in Brookfield, Illinois on February 19, 2014 And now for the grand finale! This last photograph was captured at an unbelievably slow 1/8th of a second:

Gorilla portraitGorilla inside the Tropic World exhibit at the Brookfield Zoo in Brookfield, Illinois on February 19, 2014

So, how can one create sharp photographs at such slow shutter speeds? I used the following approach:

1. Secure the camera to a tripod.
2. Use a sturdy ballhead or gimbal head.
3. Use flash to "freeze" subject movement.
4. Wait for the subject to remain relatively still.
5. Use good long lens technique--gently roll your finger over the shutter button and lay your left hand on top of the lens to minimize vibration when the mirror pops up.

Good luck out there!