EXCERPT page containing first few paragraphs. 2019-09-23 11:38:58
UA_SEARCH_BOT_null @ 18.207.136.184
Effects of Diffraction Blur on Color Aliasing
Cameras without an anti-aliasing filter are prone to high-frequency artifacts which show up as colored speckles or edges aka color aliasing. These “Christmas tree” effects can be very distracting in an image that is reproduced at a larger size.
By stopping down, diffraction begins to reduce aliasing artifacts by introducing a level of blur by degrading contrast at all structure sizes, and by making a larger blur circle, effectively acts like an anti-aliasing filter. The aperture at which this occurs depends on the size of the photosites, and in rough practical terms, the sensor size*.
* Strictly speaking the sensor size has nothing to do with it, but there is a coupling: larger sensors generally have larger photosites. Moreover, depth of field requires more stopping down for equivalent depth of field on larger formats.
Article continues for subscribers...
Diglloyd Making Sharp Images is by yearly subscription. Subscribe now for about 13 cents a day ($50/year).
BEST DEAL: get full access to ALL 8 PUBLICATIONS for only 68 cents a day ($249.95)!
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.
Leica S2 + Apo-Macro-Summarit-S 120
[low-res image for bot]