EXCERPT page containing first few paragraphs. 2020-01-18 12:08:18
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Focus Shift with the Nikon 14-24mm f/2.8G (Early Tests)
In central areas, the Nikon 14-24 declines in sharpness when stopped down from f/2.8 to f/5.6.
While shooting some field comparisons in summer 2010, I observed that the Nikon 14-24mm f/2.8G declined substantially in contrast from f/2.8 to f/5.6 (see the bristlecone comparison and the road comparison in DAP). I had previously observed this effect, but it hadn’t occurred to me that this could be focus shift, because that’s rare with an f/2.8 lens.
Focus shift to the rear
The Nikon 14-24 is optimized for wide open central sharpness and it offers high contrast without the usual haze. But the compromise was focus shift when stopping down.
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- 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.
