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Detecting and Mitigating
One way to see field curvature without even taking a picture is to use the Live View feature of most cameras (at maximum aperture). A test chart or newspaper taped to a wall can work well, so long as the camera is parallel to the subject.
Using Live View, focus at center, then move towards the edges, observing image sharpness. Refocus off-center and determine if the image becomes sharper—if so, you’re seeing field curvature (assuming you’ve aligned the camera squarely to the target). Keep in mind that off-center, there are other aberrations getting stronger, so the effect can be less than obvious with some lenses.
For more on testing a lens for field curvature, see How to Test a Lens — Field Curvature.
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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.