Photophys.com: The Science of Photography

Introduction to Photographic Science (Science for the Curious Photographer)

Comments[6] 09:52PM Jun 15, 2009 by Charles in General

Excerpts from my book started appearing on Michael Reichmann's site today.  Traditional publishers have not expressed any interest yet; in fact, none of them has seen more than the title and table of contents.  I am now considering "Publish on demand" perhaps with Lulu.com or Authorhouse.com.  That would produce an expensive paperback available on Amazon.com and elsewhere, and would permit me to purchase less expensive copies to distribute on my own.  I could also sell eBooks at much lower rates.

 In any event I expect a small audience for the book because it is really fairly high level science.  I think a love of science is required as well as a scientific way of looking at the world.  Besides that, there are equations, graphs, and tables.  It does not tell anyone how to use their camera, but rather provides answers to questions such as:  what does ISO sensitivity mean, what is the signal-to-noise ratio, what are color spaces, how does a lens coating work, what is a circular polarizer, etc.  The information and the level are similar to that found in the Handbook of Photography and the FOCAL Encyclopedia of Photography, except of course my book is much more up to date.  Keep tuned.  I will let you know what happens.

Galapagos Photoshoot via the Tip Top II

Comments[0] 10:26AM May 30, 2009 by Charles in General

On May 17 we returned from a wonderful tour of the Galapagos Islands.  I was not prepared for the underwater wonders.  My vision is limited without glasses, and I had not arranged for contact lenses.  Also, I did not have good underwater photographic equipment.  However, land, sea, and air visible above water provided unequaled opportunities for nature photography.  I made a couple of thousand images primarily with a 100-400mm IS lens on my Canon 40D camera.  A sampling of these images can be seen at this link.

I find that portraits of animals and birds in their natural habitat can be satisfying.  However, it is much more of challenging and satisfying to capture wildlife in action.  I was fortunate to be able to see birds catching fish, lizards, and even other birds.    One of the photographs linked above shows a Lava Gull with a lizard in his beak and apparently attached to his eye.  This was one of a set of six photographs of the Gull-lizard encounter.  As you can see from this set, the outcome is not clear.   I also observed and photographed a Galapagos Land Snake attempting to eat a lizard.

I love nature photography because it gives me a new window on the world.  I see things in detail that I previously missed.   Sometimes this involves the microscopic world that is revealed by macrophotography.  Other times it comes from action shots that catch things that were too fast for my eyes and brain to register.  My images from the Galapagos show many things that my “nakedâ€� eyes missed.  One striking example involves Storm Pertels.  These small birds dart about and are very difficult to photograph.  I thought that I would have to be satisfied with a wide angle shot of a swarm of petrels above their nesting area in a lava field.  I was also photographing frigatebirds in that area, and on inspection of the images I found that a female frigatebird had sagged a petrel in flight.

Art/Photography and the Brain

Comments[1] 10:42AM Feb 18, 2009 by Charles in General

Writing “Science for the Curious Photographerâ€� has been a wonderful learning experience for me.  In fact, it has been life altering.  I never before realized the amazing job that our brain does in converting relatively poor 2D images from our two eyes into a stable, colored, 3D illusion of the world.  We perceive as real a representation, based on statistical inference, that is subject to contradictory illusions.  Psychologists are beginning to understand the mysteries of vision and are even exploring why some images appeal to the human mind more than others.  Michael Gazzaniga’s book, “Human,â€� is a great resource for those who are trying to understand the uniqueness of the human mind.  Also, Daniel Tammet’s elegant book “Embracing the Wide Skyâ€� presents an accessible and succinct introduction to the wonders of vision in the chapter “Light to Sight.â€�  My research has led me into the worlds of Surreal Art, Op Art, and Computer Vision.  All of this has enhanced my love of photography and image processing.

CNPA Outer Banks Photoshoot

Comments[0] 11:11PM Feb 12, 2009 by Charles in General

The Carolinas' Nature Photographers Association (cnpa.org) is a great organization.  On January 16 we gathered at Kill Devil Hills, NC, for a weekend of nature photography.  Saturday, Jan. 17, was reported to be the coldest day in five years, and on Sunday the 18th it rained all day.  However, 52 great images were submitted for the weekend photo contest on Sunday night.  We got together on Monday morning to view the images and to hear the judges conclusions.  You can see the images here.

 On Saturday at sunrise I was standing with a group of photographers in a field near Pungo Lake.  We were trying to photography Snow Geese, but they were too far away for my 100-400mm lens.  It was beautiful but cold (12F), and I was looking around for other photo opportunities.  Behind us were weeds and bamboo shoots backlighted and glistening.  I made a number of photographs handheld with my 28-135mm IS lens without really realizing what a wonderland of ice crystals was being displayed.  When I studied the images on my notebook computer that night, I saw the forest of crystals.  One of my images is shown here.  This image won second prize.  It is interesting to note that birds were not the subject of any of the award winning photographs.

Expanded TOC for "Science for the Curious Photographer"

Comments[2] 12:45PM Jan 31, 2009 by Charles in General

I have made a two level Table of Contents for SCP.  If you are particularly interested in any chapter, please contact me.  I would be happy to send you a pdf copy for your review and comments.  Here is the TOC.

How to get really high magnifications

Comments[1] 06:13PM Jan 20, 2009 by Charles in General

In the next few months I will be uploading selected chapters from "Science for the Curious Photographer" in hopes of getting some feedback.  Today I am making available Chapter 12 on close-up photography for viewing by means of a pdf file.  This chapter contains equations and discussion that would be appropriate for an advanced course on photography.  It can be accessed by clicking the title:

How to Get Really High Magnification (928 KB)

I would be delighted to learn of errors or of differences of opinion about my conclusions.

Photophys.com is open again!

Comments[0] 02:57PM Jan 10, 2009 by Charles in General

After a respite Photophys.com is back.  I am happy to announce that my book, “Science of the Curious Photographer,â€� has been finished and is available as a CD.  At present the number of copies is very limited, and I am making them available to local nature photographers.  In the near future I will have more copies and will arrange for wider distribution.  We are still in negotiations about hardcopies.  The hardcopies will be more expensive, and the figures and photographs will not look as good as they do on computer screens.  For the Table of Contents and blurb click here.

I will post corrections and comments on this site.  Also, I welcome your comments about the book.

The vanishing DoF at large magnifications – CombineZM to the rescue

Comments[1] 05:14PM Jul 15, 2007 by Charles in General

When the magnification is greater than 1X, the depth-of-field (DoF) becomes paper thin; and 3D objects cannot be imaged very well.  For subjects that are completely still, one can take a series of photos with different focus setting and then attempt to combine them.  By this I mean the construction of a composite image by using the sharp parts of the component images.  If you have tried this, you know that there are problems.  First of all, our camera lenses are not telecentric, and the magnification changes with the focus setting.  Therefore, the first step is to resize the images before trying to bring them into register.  With more than a couple of images, this gets to be a lot of work.

As you probably know, there are computer programs for image reconstruction and DoF expansion.  One review of such programs can be found at:  http://www.crystalcanyons.net/pages/TechNotes/3DMicroMacro.shtm

Here Prof. Hart compares various programs and concludes that the freeware program CombineZX does rather well.  Information about Combine ZM can be found at:

http://www.hadleyweb.pwp.blueyonder.co.uk/CZM/Manual/combinezm_help.htm

 
A couple of weeks ago I downloaded CombineZN and finally got around to testing it.  I have only used the automatic mode, but I am impressed.  Here I show a few images to serve as an illustration.  The shots were taken with a Sigma 150mm lens at close to 1:1 focus (1X magnification) with 68mm of extension tubes added to bring the magnification to 1.68.  In all cases I used f/5.6.  I took seven shots with a change in focus the same direction each time.  These are photos of a fly about 2mm in length that has been trapped by a Cape Sundew plant.  In the first image (148 kb, jpg)  I attempted to focus on the closer eye, and the problem with DoF is obvious.  The second image (209 kb, jpg) was constructed by CombineZM from a stack of seven jpg images.  This image was satisfactory from the start, but I did improve a few places with the clone tool.  I have a lot more to learn about CombineZX, but I thought that you might enjoy playing with it also.

By the way, the plant is small.  This photo (228 kb, jpg) puts it all into context.   

Diffraction Problems in Macro Photography

Comments[1] 04:11PM Jul 15, 2007 by Charles in General

Avoiding diffraction problems in macro-photography:  We all know about the loss of resolution that occurs with small apertures (large f#’s), but it is easy to forget that the effective f# is not equal to the one shown in the camera.  The f# we need to use is: f#(effective) = f# times (1 + m).  Here m is the magnification.  My Sigma 150mm macro lens will focus to 1X magnification.  At that point all the f#’s shown should be multiplified by two in order to estimate the DoF and the effect of diffraction.  It gets worse with extension tubes.  I add 68mm of additional extension to get 1.68X and the f#  shown needs to be multiplied by 2.68!  When I forgot this factor and set the camera for f# = 22, I got unsatisfactory images.  As an example take a look at this figure:

Sundew plant (100% crop of 1X macro photos) (635 kb, jpg)

The setting of f/4.5 is probably the best and f/8 is satisfactory, but f/22 is fuzzy.  You can find useful information in John Shaw's book, "Closeups in Nature."

All chapters temporarily off-line

Comments[0] 09:20AM Jun 02, 2007 by Charles in General

Chapters 1 - 9 have been taken off-line while revisions and consolidations are being made.  The tentative table of content of contents can be seen here.

Chapter 9 at last

Comments[0] 06:41PM May 07, 2007 by Charles in Lenses

I am now posting Chapter 9: 
Coming to terms with real (compound) camera lenses  (pdf, 230 kb)

This chapter contains math, but I think the basic ideas can be appreciated without working through the derivations.  Of course, some of us love math, and that is why it is here.  An equation is certainly worth a thousand words!  As always, comments will be appreciated.  Also, please continue to report suspected errors via comments or in email.  Thanks.

Birding in Costa Rica

Comments[0] 06:16PM May 07, 2007 by Charles in General

Exploring Costa Rica with a camera was a great adventure.  We spend spend two nights each at five life zones.[Read More]

Birding trip to Costa Rica

Comments[3] 10:55PM Apr 06, 2007 by Charles in General

I will be on a photo shoot in Costa Rica for the next two weeks.   "Science in Photography" will be on hold, but I will be having fun trying out a Canon 70-300mm IS lens, a Manfrotto 676B monopod, and a Better Beamer.

Updated Table of Contents

Comments[0] 03:11PM Mar 31, 2007 by Charles in General

I have completed Chapter 9 on understanding compound lenses, and I am now getting help with proof reading.  Also, I have updated the Table of Contents.  The new version is available here.

Figures for Chapter 4

Comments[0] 08:43PM Mar 15, 2007 by Charles in General

New figures have been added to Chapter 4 (pdf, 188KB) to illustrate changes in image size and perspective, and work is proceeding on Chapter 9: 

 Tentative Title for Chapt. 9:

 Coming to terms with real (compound) camera lenses

(Nodal planes, entrance pupil, stops, and all that)

I expect to be able to post Chapter 9 in a couple of weeks.