Photographing Phaseolus vulgaris (Yellow Wax Beans)

wax bean pod and beans

By Casey Murphy

aseyca89@hotmail.com

Rochester Institute of Technology

Biomedical Photographic Communications

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Introduction

As I perused the produce selection at the local grocery store, I noticed something that I had never seen before on display next to the basket of green beans. They appeared to be green beans, except that they had yellow skin and a sign on their basket called them wax beans. I inspected them further and began to think about their photographic potential. I noticed the textures of the pod and the bean within and decided that I would like to explore it further with macro photography.

Subject Information

Phaseolus vulgaris refers to many different common beans including bush beans, kidney beans, green beans, and wax beans. Yellow wax beans originate from the tropical climates of Central and South America, however they are now grown in temperate climates as well.  The beans are available year round, but their peak season lasts from late July to late September.
The yellow wax bean is extremely similar in appearance to green beans except that the pod is yellow in color and its skin is thinner and has a different, more waxy texture to it.
The taste is said to be more subtle than that of the green bean, but they are often used in the same cooking applications. Yellow wax beans commonly appear in stir-fries and soups. The beans are also frequently canned or pickled.

Equipment  
  • Pentax K20D Camera body
  • Pentax 50mm Macro lens
  • Pentax bellows
  • Bausch and Lomb 20mm and 45mm thimble lenses
  • Fiber Optic lights
  • Copy stand, black velvet for background
wax bean
Lighting

For all of my images I used some variation of two different lighting techniques. The first technique was a reflected light set up with two lights on opposite sides above the subject. The second technique used was a trans-illumination set up with two lights on opposite sides under the subject. Here are diagrams of these two set-ups respectively:

reflected lighttransillumination

Depending on the feature of the subject that I was trying to photograph, one of the lights may have been further away than the other, or one of the lights might have been turned off to reveal texture or structure that was otherwise hidden.

Photographing

For all of my photographs, the camera was positioned on the copy stand looking straight down on the subject. All of the photographs showing the entire subject were taken with the 50mm macro lens, and all of the close ups were taken with the bellows and the thimble lenses.
Most of the photographs were taken with a small aperture to obtain maximum depth of field, and a low ISO to prevent noise. These settings required the use of longer shutter speeds and most pictures were taken at between 4 and 10 seconds.
To reduce shake and vibration in the image, I chose the Pentax K20D, which has vibration reduction built into the body rather than the lenses. This feature means that vibration reduction is available when using a bellows system, something that is not available with other camera models. The magnification varies between images, but the range was between .5x and 7x. 
When choosing what to photograph, I separated the wax bean into three different sections, which were the pod, the shell around the bean, and the bean itself. As I photographed, I tried to explore these three things separately as well as how they are each related.

Problems While Photographing

Despite using the camera’s vibration reduction feature, I still encountered a lot of blurriness in my images due to vibrations. To help reduce this I used a cable release so that there was no shake when pressing the shutter. Furthermore I made sure to keep any sources of vibration, such as the fans in computers or the fiber optic lights, as far away from the camera and subject as possible.
Focusing is always difficult at high magnifications, especially when shooting with a small aperture. In order to obtain sharper images I would open the aperture to its widest f-stop while focusing and then return to a smaller aperture before photographing, and then I would change the focus by very small increments between image captures.
While photographing with the trans-illumination technique, I noticed that I was having issues with large amounts of flare on the edges of the subject. To fix this, I used dark cloth to create an outline around the subject, which helped to reduce the amount of light leaking around the subject.

About The Photographer

I am a fourth year student at the Rochester Institute of Technology in Rochester, New York. I will graduate in May of 2011 with a Bachelors of Science degree in Biomedical Photographic Communications. I am undecided on my goals upon graduation, but I am interested in a career in photography.

Contact Information: Casey Murphy aseyca89@hotmail.com 614-323-4329

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