Friday Jan 10, 2014

Confusion about the circle-of-confusion

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.

Sunday Dec 22, 2013

Corrections to "Science for the Curious Photographer"

There are no additions to the list.  The latest printing of "Science for the Curious Photographer" is identified by the CRC Press logo that appears at the lower right hand corner of the front cover, on the spine, and on the back cover.  Most of the typos have been corrected, but unfortunately a few remain.  The updated list of corrections with the remaining ones shown in red can be found here.

Thursday May 23, 2013

What is a Fake Photograph?

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.

Monday May 13, 2013

Samyang 14mm Lens: Revisiting the Hyperfocal Distance

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.” 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.

Saturday May 04, 2013

What is the Canon 6D Good For?

One gets the impression that the Canon 6D was designed without serious consideration about what the competition might do. The 6D is an affordable full frame DSLR, but its feature set looks very weak when compared with that of the recently released Nikon D600.1,2 The D600 offers 14 stops of dynamic range at low ISO,3 a 24 megapixel sensor, dual card slots, 39-point AF system with 9 cross-type AF points, built-in flash, and 100% viewfinder coverage. In contrast, the 6D lags in all these areas and is missing the dual card slots and the flash unit. As some compensation, the 6D offers build-in Wi-Fi and GPS. In essence the 6D is a full frame version of the Canon 60D (APS-C sensor) with the serious omission of the flash and the articulated LCD screen.[Read More]

Sunday Apr 07, 2013

The Effective F-Stop of Your Macro Lens

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]

Monday Mar 18, 2013

Update to corrections for SCP

The latest printing of "Science for the Curious Photographer" is identified by the CRC Press logo that appears at the lower right hand corner of the front cover, on the spine, and on the back cover.  Most of the typos have been corrected, but unfortunately a few remain.  The updated list of corrections with the remaining ones shown in red can be found here.

Sunday Mar 03, 2013

Should APS-C Camera Users Consider Moving to the Micro Four Thirds (mFT) Format

These comments concern mainly amateur nature photographers who would like to reduce the size and weight of their gear. I am the happy owner of a Canon 7D that I use primarily for wildlife photography with telephoto lenses. I also use a Canon 60D for landscapes, macrophotography, and night sky photography. When I travel with two camera bodies and a set of lenses including my Canon 100-400mm, my backpack is too heavy. Why not switch to one of the new mFT cameras and cut the weight by a factor of two? The Michael Reichmann’s recent review1 of the Olympus OM-D on and the in depth review2 of the same camera on indicate there will be little, if any, loss in image quality relative to APS-C with the smaller format.[Read More]

Saturday Mar 02, 2013

Landscape Astrophotography without Star Trails

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.

Landscape Astrophotography without Star Trails (647kb)

Latest printing of "Science for the Curious Photographer"

“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.

Thursday Dec 06, 2012

Corrections for the first printing of "Science for the Curious Photographer"

Errors and typos found in the first printing of SCP are listed here.

Saturday Aug 11, 2012

Focusing on stars for night sky photography

Years ago I enjoyed astrophotography with an Olympus OM-1 35mm camera mounted on a 5” Celestron telescope, but only recently have I realized the accessibility of great astrophotography to anyone with a DSLR and a tripod. Night sky photography is so much easier and better now with digital cameras. If you have not discovered the wonders of the sky at night, I suggest you look at Manel Soria’s article on Landscape Astrophotography at Also Phil Hart’s eBook, Shooting Stars, provides an excellent introduction.[Read More]

Wednesday Jul 04, 2012

Southern Utah again and again with a bit of Arizona

We only discovered the scenic wonders of Southern Utah in 2011, and we have made up for lost time by visiting there two more times since then. Our first visit was in the spring of 2011, and I reported on that trip in my post of July 11, 2011. We returned in the fall of 2011 and revisited Arches, Canyonlands, and Bryce Canyon NP’s.[Read More]

Monday Jul 02, 2012

Iceland Anyone?

Iceland is only about five hours from New York, and probably offers the greatest scenic diversity in the world for an area only about the size of West Virginia. I hardily recommend Iceland for interesting vacations and wonderful nature photography. We visited Iceland in 2006 and took the Ring Rider road trip that was offered by Iceland Air. That included a car and “farm stays” spaced around the island. We saw magnificent waterfalls, geothermal areas, an arctic lagoon filled with ice bergs, and a variety of arctic birds. On top of that, there is European history dating from 870 CE, and ancient Nordic myths in the form of sagas.[Read More]

Thursday May 24, 2012

iPad 2 versus the “new” iPad: How much resolution is enough for photographers?

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:

Resolution - iPad 2 vs new iPad (394kb pdf)

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