Appreciation through Understanding
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: