EXCERPT page containing first few paragraphs. 2019-03-18 17:39:23
UA_SEARCH_BOT_null @ 18.104.22.168
This page shows focus shift of the Nikon AF-S NIKKOR 70-200mm f/2.8E FL ED VR at 200mm at a reproduction ratio of roughly 1:7.
The ratio of 1:7 was chosen because this is a tight head shot distance, thus making that reproduction ratio highly relevant to real world shooting. Sharp eyes are critical in a portrait, hence focus shift is a key performance attribute.
Nikon AF and focus shift
There is a major contextual consideration as to whether the focus shift matters or not: evidence suggests that some cameras such as the Nikon D810 with the latest firmware in fact modify the autofocus system to compensate for focus shift. Thus if the shooting aperture is set to f/5.6, the camera optimizes focus for an assumed shooting aperture of f/5.6, which means that through the viewfinder the image could appear slightly soft!
Article continues for subscribers...
Diglloyd Advanced DSLR is by yearly subscription. Subscribe now for about 16 cents a day ($60/year).
BEST DEAL: get full access to ALL 7 PUBLICATIONS for only 68 cents a day ($249.95)!
Diglloyd DAP is DSLR-oriented, but also contains workflow and other topics. Much of the focus is on Canon and Nikon but also Pentax and Pentax medium format.
Special emphasis is placed on lens evaluation, focusing on Canon and Nikon and Sigma lenses, but with a few others like Rokinon/Samyang.
- Make better images by learning how to get the best results right away.
- Save money by choosing the right lens for your needs the first time, particularly some of the new Sigma Art lenses vs Nikon and Canon.
- Workflow discusses image organization, raw conversion and post processing. Many examples show processing parameters for direct insight into how the image was converted.
- Jaw-dropping image quality found nowhere else utilizing Retina-grade images up to 28 megapixels filling up to 5K display, plus large crops [past 2 years or so].
- Real world examples with insights found nowhere else. Make sharper images just by understanding lens behavior you won’t read about elsewhere.
- 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.