ISO settings are held over from film cameras. Film photographers had to choose the proper film speed to capture the correct image. For example, some speeds work best in bright daylight, while others are ideal for sports photography. Setting your ISO on your Nikon D40 is exactly like choosing a film speed. Designed for amateur and beginner photographers, the D40 includes Auto-ISO settings to help take the guesswork out of photography.
What ISOs Do
An ISO is an exposure setting, helping to change the amount of light a camera takes in with each photo. It works in conjunction with other settings, such as shutter speed. Lower ISOs, such as 200, are slow speeds. They allow less light to enter the camera than faster speeds, such as 1600. Slow speeds are most often used for stationary items, such as portraits and landscapes. The images produced by slow speeds are usually sharp. Faster speeds are used for action and sports shots, or some low-light shots. These faster ISOs help prevent blurring, but the images are often grainier than those taken at lower speeds. Photographers adjust ISOs as they shoot to account for lighting changes, such as clouds temporarily covering the sun during an outdoor photo session.
Program Modes
The Nikon D40 offers several automatic program modes for the novice photographer. These modes include Landscape, Portrait and Sports. When you activate these modes, the camera will always use its Auto ISO feature to set the exposure speed. The camera will use the program mode you chose to set the exposure parameters, and it will change the ISO within those parameters based on the light it senses. For example, if you have it set on the Sports mode, it may set the Auto ISO to fall between 800 and 1600 ISO, based on the lighting conditions.
Manual Modes
The Nikon D40 allows more experienced photographers to set manual modes. These modes include shutter priority, aperture priority and full manual. You must change your custom settings for Auto ISO to work with manual modes. While adjusting your settings, you choose the ISO parameters for each mode. When you use the modes, the camera will automatically adjust the ISO for you.
Manual Mode Settings
When setting your ISO parameters for the manual modes, there are several options. Choosing "Off" means the ISO must be manually set. This is the camera's default setting. Choosing "On" means the camera will automatically adjust your ISO for each photo. If you select "Max Sensitivity," you can enter a certain ISO range from which the camera can choose when automatically adjusting your ISO. This is especially helpful if you're trying to get a specific shot, such as a blurred athlete running in front of an unblurred fence. Only a certain range of ISOs will create such a shot. Your final Auto ISO choice in the manual modes is "Min Shutter Speed." This allows your Nikon D40 to automatically adjust the ISO only when the light at your chosen shutter speed falls below the level required for that shutter speed.
Tags: camera will, automatically adjust, manual modes, adjusting your, camera will automatically, certain range