The Nikon Autofocus System, 2nd Edition

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Other Considerations

Now that we’ve gone through most details of the Nikon AF system, it’s time to look at other topics that are peripherally related to AF and impact your ability to effectively create sharp images. In this chapter, I’ll cover a variety of topics, including detailed definitions, hyper-focal distance, lens quality issues, and how to fine-tune your AF system with an aftermarket product.

Understanding Focus, Clarity, and Sharpness

Here are the technical definitions of focus, clarity, and sharpness.

Focus

Focus is the point at which light rays converge on an imaging sensor and produce a clear visual definition of a subject (figure 7-1). In digital photography, an object is in focus if light from that object converges on an imaging ...