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Case Study: Contrast Detect Autofocus Error, Nikon D800E
Zoomed-in Live View along with contrast-detect autofocus* are ostensibly highly accurate as a means of obtaining precise focus. If only this were true!
Contrast-detect autofocus is a contrast-peaking type of focus using image data off the sensor itself, not a phase-detect system as with conventional autofocus
My experience over several years of using contrast-detect autofocus on various Nikon camera bodies shows that contrast-detect autofocus can generate significant focus error. While it usually produces a highly accurate result, there have just been too many cases with too many lenses on multiple camera bodies where it does not produce the best result. Consequently, one cannot rely upon it for critical work.
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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.
