Imagery: Auto - Large Table of Contents

EXCERPT page containing first few paragraphs. 2019-09-23 11:43:52
UA_SEARCH_BOT_null @ 18.207.136.184

Focusing Accuracy When Testing

It is easy enough to prove that a lens is better than itself!

Focusing at center with Live View using a loupe can yield optimal focus for the center easily enough.

But the trick is the zone of focus. Even when there is no discernible difference at center, subtle focus differences can result in significant variation in sharpness at the corners or edges and in front of and behind the point of focus. That’s because there is some depth of field which allows small variations at center, which throw the other areas slightly more into or out of the sharp zone of focus. It is field curvature that is at play, but also just simple depth of field, and slight asymmetries.

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 68 cents a day ($249.95)!

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.

diglloyd Inc. | FTC Disclosure | PRIVACY POLICY | Trademarks | Terms of Use
Contact | About Lloyd Chambers | Consulting | Photo Tours
RSS Feeds | Twitter
Copyright © 2019 diglloyd Inc, all rights reserved.