EXCERPT page containing first few paragraphs. 2020-07-02 14:03:18
UA_SEARCH_BOT_null @ 188.8.131.52
Brand-new blur is not confined to any brand or price level.
A slight defocus can help reveal lens problems that are otherwise muted by depth of field; if a lens has asymmetry: a slight defocus can make one side sharp and the other blurred. Alternately, a non-planar subject such as a gently upward-sloping hillside with generally similar subject matter can show a cut of sharpness that is skewed forward on one side.
As shown below, a brand-new Leica 180mm f/3.5 APO-Elmar-S had asymmetric sharpness. Several tests all confirmed the same problem. A 2nd sample of the 180/3.5 was not available, so a camera lens mount to sensor misalignment cannot be ruled out. However, no asymmetry was seen with the the 70mm f/2.5 Summarit-S ASPH on the same scene on the same camera body, and camera misalignment is generally more noticeable with a shorter focal length.
Article continues for subscribers...
Diglloyd Medium Format is by yearly subscription. Subscribe now for about 33 cents a day ($120/year).
BEST DEAL: get full access to ALL 8 PUBLICATIONS for only 68 cents a day ($249.95)!
These systems are hugely expensive, so make the right choice for your own needs (full frame vs medium format).
- In-depth lens evaluations covering behaviors not likely to be found anywhere else, based on real-world field shooting.
- How to configure menus and buttons and best operating practices, gotchas and how-to.
- Real world examples with insights found nowhere else. Make sharper images just by understanding lens and camera behaviors.
- Jaw-dropping image quality found nowhere else utilizing Retina-grade images up to 100 megapixels filling up to 5K display, 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.