Photographers can change the lens aperture settings on the Nikon D70 using the aperture-priority or manual shooting modes. The range of options available to the photographer depends on which lens is attached to the camera body. Fast, or prime, lenses are more expensive than standard lenses but offer the largest apertures.
What Is Aperture?
The aperture, also called the f-stop, is the size of the lens opening. It controls the amount of light allowed through the lens and combines with shutter speed to expose a picture. With traditional film cameras, the aperture is controlled by turning a ring on the lens. In digital SLRs, aperture is set through the electronics inside the camera body. The f-stop number is a fraction calculated by the aperture's diameter divided by the focal length of the lens.
Using D70 in Aperture-Priority Mode
Aperture-priority mode is one of the semi-automatic shooting options for the D70. It's marked as "A" on the camera's main control dial. Using this setting, the photographer chooses the aperture and the camera automatically sets the corresponding shutter speed. Set the aperture using the sub-command dial, found to the front of the shutter button. Rotate the dial and look at the LCD window until you see the correct "F" number appear.
Using D70 in Manual Mode
In fully manual mode, marked with an "M" on the mode dial, you will set the aperture and the shutter speed. This will give you complete control over the picture's exposure. As in aperture-priority mode, turn the sub-command dial to set the aperture. Use the right around the main control dial to choose the shutter speed. Typically, the larger the aperture, the faster the shutter speed that can be used.
Why Aperture Matters
Aperture is important because it controls the depth of field of a picture. A lower aperture allows more light through the lens and creates a shallow depth of field. That means the background of your picture will be blurry while the subject is in sharp focus. A higher aperture sharpens the background focus. You can see the depth of field of a picture by pressing the depth-of-field preview button on the D70 while looking through the viewfinder. The button is on the front of the camera on the lower left side of the lens.