Imagery: Auto - Large Table of Contents

EXCERPT page containing first few paragraphs. 2024-03-28 04:38:08
UA_SEARCH_BOT_null @ 54.208.238.160

For full access, subscribe here. Or click title to login.

Testing for Focus Shift and Secondary Color 📹

Detecting focus shift at close range (1:5 to 1:40 magnification) is straightforward. At greater distance, suitable targets are harder to find, but a landscape scene with level and uniform detail can work e.g., a gravel path or any scene with a central subject having good detail and with a fore/background. A good example of this can be seen in the Nikon 14-24mm case study.

Any target similar to the one shown at right will work for a close range test e.g., a ruler. High contrast black and white with regular lines or patterns are most useful, both for ease of focusing and analysis, as well as checking for secondary longitudinal chromatic aberration.

Article continues for subscribers...

Diglloyd Making Sharp Images is by yearly subscription. Subscribe now for about 13 cents a day ($50/year).
BEST DEAL: get full access to ALL 8 PUBLICATIONS for only about 75 cents a day!

Diglloyd Making Sharp Images articulates years of best practices and how-to, painstakingly learned over a decade of camera and lens evaluation.

Save yourself those years of trial and error by jump-starting your photographic technical execution when making the image. The best lens or camera is handicapped if the photographer fails to master perfect shot discipline. High-resolution digital cameras are unforgiving of errors, at least if one wants the best possible results.

  • Eases into photographic challenges with an introductory section.
  • Covers aspects of digital sensor technology that relate to getting the best image quality.
  • Technique section discusses every aspect of making a sharp image handheld or on a tripod.
  • Depth of field and how to bypass depth of field limitations via focus stacking.
  • Optical aberrations: what they are, what they look like, and what to do about them.
  • MTF, field curvature, focus shift: insight into the limitations of lab tests and why imaging performance is far more complex than it appears.
  • Optical aberrations: what they are, what they look like, and what to do about them.
  • How to test a lens for a “bad sample”.

Intrigued? See Focusing Zeiss DSLR Lenses For Peak Performance, PART ONE: The Challenges, or (one topic of many) field curvature.

Target

diglloyd Inc. | FTC Disclosure | PRIVACY POLICY | Trademarks | Terms of Use
Contact | About Lloyd Chambers | Consulting | Photo Tours
RSS Feeds | X.com/diglloyd
Copyright © 2022 diglloyd Inc, all rights reserved.