EXCERPT page containing first few paragraphs. 2024-04-19 13:53:44
UA_SEARCH_BOT_compatible_botmozilla/5.0 applewebkit/537.36 (khtml, like gecko; compatible; claudebot/1.0; +claudebot@anthropic.com) @ 3.133.109.30
For full access, subscribe here. Or click title to login. 
(prototype)
Field Curvature at Distance, Zone of Focus Placement (NYC Buildings)
This example turns out to be an excellent demonstration of how focus placement can lead to erroneous conclusions about peak sharpness: small changes in focus can bias the zone of focus in a way that will soften the edge areas relative to t.he center: field curvature.
General discussion
Even at f/4 as here the zone of sharp focus can render some areas very sharp with small changes in focus. But those same small changes might render the edge areas sharp or slightly soft while still leaving the center at peak sharpness. For absolutely best results, one has to balance the placement of the zone of focus for the particular, and this is true of just about every lens. See the MTF discussion for the 55/1.4 APO-Distagon to see this in chart form. Your author has also seen “through focus” MTF charts which further clarify the behavior, but regrettably these are not available for publication.
Article continues for subscribers...
Diglloyd Guide to Zeiss is by yearly subscription. Subscribe now for about 21 cents a day ($75/year).
BEST DEAL: get full access to ALL 8 PUBLICATIONS for about 75 cents a day!
Diglloyd Guide to Zeiss offers comprehensive integrated coverage of Zeiss DSLR lenses for Canon and Nikon. Nearly a decade in the making, it covers everything you need to know for every lens in the ZF.2, ZE, Milvus and Otus lines. Guide to Mirrorless and Zeiss ZM rangefinder lenses in Guide to Leica.
- Make better images by learning how to get the best results right away. A “cheat sheet” saving months of ad-hoc learning—Guide to Zeiss is much more than lens reviews.
- Save money by choosing the right lens for your needs the first time. A year’s subscription covering ALL these lenses is a tiny fraction of the cost of just ONE lens.
- Make better images, a sort of “cheat sheet” saving yourself months or years of ad-hoc learning—Guide to Zeiss spells out best practices.
- Real world examples with insights found nowhere else. Make sharper images just by understanding lens behavior you won’t read about elsewhere.
- Jaw-dropping image quality found nowhere else utilizing Retina-grade images up to full camera resolution, plus large crops.
- Aperture series from wide open through stopped down, showing the full range of lens performance and bokeh.
- Optical quality analysis of field curvature, focus shift, sharpness, flare, distortion, and performance in the field.
Want a preview? Click on any page below to see an excerpt. And see Lloyd’s articles for Lenspire.Zeiss.com.
Nikon D800E + 55/1.4 APO-Distagon prototype