diglloyd publication
Imagery: Auto - Large Table of Contents

Criticality of Focus

This page establishes a baseline for understanding just how important focus accuracy is to exploiting the 24+ megapixels of the Nikon D3x. The goal is not any absolute metric, but rather simply to show that small focus differences (eg 1% of the subject distance) can produce subjectively quite different results, with high or lower contrast and more or less color fringing.

Resolution target

A resolution target was photographed at a distance of approximately 9 feet (2.7 meters) at a reproduction ratio of approximately 1:24. A tripod, mirror lockup and remote release were used on the D3x. Live View was used to focus wide open at f/2 on the Zeiss ZF 100mm f/2 Makro-Planar, zoomed in maximally for the best possible accuracy.

As seen below, the target shows some vignetting at f/2, and some uneven illumination (numerous Solux bulbs for near-daylight). We are concerned only with the center portion.

Article continues for subscribers...

Already a subscriber? CLICK HERE TO LOG IN

Since 2006, Diglloyd Advanced Photography is the authoritative review and reference for DSLRs and their lenses: Canon and Nikon primarily, but also Pentax and some medium format. Reviews of key DSLRs are included, but the primary focus is on lens performance. Also included is a wealth of technique and workflow approaches.

DAP includes thousands of pages of exclusive coverage and high resolution Retina-grade examples detailing Canon and Nikon DSLR bodies and their lenses, with in-depth analysis of sharpness and contrast, color, bokeh, vignetting, distortion, MTF, and flare, behavioral and practical usage.

  1. Explore the table of contents
  2. View Lloyd’s Blog
  3. SUBSCRIBE NOW for $ per year.
resolution target
The well-used target. The strip of center patches is stacked, for “depth”.

diglloyd Home Page | Terms of Use | PRIVACY POLICY | Contact
Copyright © 2008-2016 diglloyd Inc, all rights reserved.