The D7200’s auto ISO feature isn’t just for beginners. It can also help experienced photographers get sharp shots at the lowest possible ISO – automatically.
If you go to the ISO sensitivity settings on the Photo Shooting menu and switch Auto ISO sensitivity control on, you’ll see that you can then choose two further settings: Maximum sensitivity and Minimum shutter speed.
The Maximum sensitivity is the highest you want the camera to go. Set this according to your own personal opinion about when the quality drops below an unacceptable level. I generally choose ISO 6400.
The Minimum shutter speed is the slowest speed you want the camera to use before it starts increasing the ISO setting. You can choose this manually (you might think you can be sure of sharp handhelds shots at 1/30 sec, for example) or you can set it to Auto and leave it to the camera to work out a minimum shutter speed based on the focal length of the lens you’re using.
Once you’ve done this, the camera will measure the light for each shot and increase the ISO only enough to achieve your minimum shutter speed. You’ll get shake-free shots at the lowest ISO possible.