When shooting a portrait, the best place to focus is on the tip of the nose.

Depth of field is greater at ƒ/11 than at ƒ/4.

Depth of field is greater when focused at 20 feet than when focused at 10 feet.

At most apertures, at moderate distances, the depth of field extends about the same distance in front of the subject you’re focused on as it does in back of the subject.

All points from front to back within the depth of field are equally sharp.

When you look into a DSLR or SLR viewfinder, you see the depth of field exactly as the digital sensor or film will record it.

The setting at which the greatest possible area falls within the depth of field is called the hyperfocal distance.

A DSLR camera usually has a focal-plane shutter.

An object moving toward the camera can be kept reasonably sharp at a slower shutter speed than the same object moving across the field of view from left to right.

When shooting a distant mountain scene with a 100mm lens, you can produce a satisfactorily sharp image if you handhold the camera with a shutter speed of at least 1⁄60 sec.

To make water appear as an angel-hair veil of light, use an extremely fast shutter speed.

When handholding a camera, shoot at 1⁄100 sec or faster to be sure of producing a reasonably sharp image when shooting with a 100mm focal length.

A skylight filter improves the sharpness of the image.

If nothing is sharp in a picture, the probable cause is camera shake.