Appreciation through Understanding
According to Google, “Circle of Confusion” is a song, an entertainment company, and the name of a website. It also has some connection with photography. In this article it is all about CoC in photography, and why it is important. Of course, you can look up discussions of the CoC concept, its history, and associated calculations online. However, in a few paragraphs I think I can clarify the concept for photographers and show why it is useful.
The complete (476 KB) article can be found here.
We are bombarded with images from television, computer screens, newspapers, and magazines. There are advertisements, illustrations for news stories, snapshots from social media, and on and on. From time to time there are news stories expressing outrage about manipulated photographs in advertisements and, heaven forbid, enhanced photos in news stories. There are rants about “fake” photographs, and prestigious publications such as the New York Times proclaim their purity. In the nytco web site1 we find, “Images in our pages that purport to depict reality must be genuine in every way.”
The complete article (507 KB pdf) can be found here.
Also, the article has been published on Luminous-Landscape.
I recently purchased a Samyang (Rokinon, Bower, Walimex) 14mm lens after reading glowing reviews of it. For example: “It is insanely great” Tim Ashley’s Blog, “ I think it’s an insane bargain for a very sharp lens” Roger Cicala of Lensrentals, and “…may be the surprise product of the season.” Photozone.de. Overall this is a great lens, and similar lenses from the big name manufacturers cost five times as much. However, one should be aware that the Samyang beast is strictly mechanical. One must get used to that. There is no electronic contact with the camera for focus or exposure. Fortunately, focus is manageable given the large depth of field; and exposures are sort of automatic on my Canon camera in the aperture priority mode.
The complete article (414 KB PDF) can be found here.
I am doing macro photography with focus stacking again and that has forced me to revisit depth-of-field calculations as well as diffraction broadening effects. In both cases the effective F-stop of the lens is an essential parameter. So what is the effective F-stop of my macro lens?[Read More]
I like to photograph the night sky in such a way that the stars appear to be bright points of light and not lines or streaks. This is possible if the exposure time is adjusted so that the images of the stars move on the camera sensor by amounts that are not evident in enlarged images. My calculations of the required exposure times are described in the following pdf document.
“Science for the Curious Photographer” is now being shipped with the corrections that I have reported. Also, I am happy to note that photographs, illustrations, and tables have been appropriately improved. I did not see any indication that this is a “second printing.” One way to check that you have a corrected copy is to look at Table E.1 in Appendix E. In the latest printing, the table contains a left hand column giving numbers 1 – 17 for the rows.
You can find all of the reported errors listed in my December 6, 2012, blog entry. There is also a link to high resolution copies of the photographs.
A great use for iPads is the presentation of photographic portfolios. Indeed the images are beautiful, and they tend to have greater impact than similar sized paper prints. Now a new iPad has been released that offers twice the resolution of iPads 1 and 2. So the obvious question is, “how much better will my photographs appear?” To read my conclusions download the following document: