The aims of this project were to produce five of my own images in which there is a shallow depth of field, otherwise known as selective focus. An understanding of the concept of depth of field (DoF) is important in photography. It can be used to affect audience response when communicating visually via digital imagery. Shallow depth of field allows the photographer to place emphasis on a specific subject within the frame by blurring other things within view such as the background. It is commonly seen in macro photography. A large depth of field is used when having lots of information in the shot, all in focus, is the goal.
The three main factors that affect DoF are Aperture, Focal Length and the distance from the camera to the subject.
How to achieve selective focus (shallow) depth of field? In general:
- Large apertures decrease the depth of field (use low f-numbers)
- Long focal lengths decrease the depth of field
- Close distances from camera to subject decrease the depth of field
These images are examplars of the use of selective focus in nature photography by professional photographers.
The first three images below are by professional photographer Anand Varma who was commissioned to create the work by National Geographic. They are from a photographic series called Mindsuckers that explores parasitic relationships in the animal world. In particular it focuses on the ways in parasites which manipulate their host’s behaviour to be advantageous to the parasite’s life cycle. This series of works won first prize Nature stories in the World Press Photo Competition 2015.
In this image the close depth of field has been achieved by closeness to the subject and a long focal length, despite a small aperture. The image clearly illustrates the relationship between mould spores, captured here like smoke, and the ant that they colonise. The high f-number has resulted in lots of detail in the image however there is still some part of the image less sharply in focus.
This image succeeds in its central competition which highlights the symmetry in the insect specimen’s body. It is an example of a very shallow depth of field as the insect’s face is in focus but it’s front legs are not.
In this image the photographer has successfully used selective focus to illustrate the complex plant-animal interaction between a colony of ants that live inside this pitcher plant. The part of the plant in the foreground is completely out of focus and the entire background of the image is blurred with no discernible details. A long focal length and short distance from the subject have be used to create this shallow depth of field. The strong focal point of the plant’s spiraled pitcher is very effectively balanced with the small outreaching ant and the plant material in the vertically left quarter of the image.
Ziegler’s image has successfully captures the metallic luminous colour of his insect subject. Here the depth of field is as not as shallow as in some of the other exemplars. It is shallow enough to eliminate any background distractions but by using a larger f-number (smaller aperture) with the macro lens the photographer has included a lot of in focus details of the both the insect and the plant.
This image is works very well to contextualise this caterpillars in the urban environment. The depth of field used is allows the viewer to be able to see the housing in the background but it is shallow enough for them to be out of focus. By using the selective focus and placing the caterpillar on the 1/3 vertical line in the composition the photographer has created a successful image emphasising the insect as subject. It is a great example also of steepened perspective. We know that the caterpillar is not bigger than a house in reality, however the low viewpoint and closeness of the subject to the camera has distorted realistic proportion to great effect.
By being very close to the subject, presumably using a macro lens, and compositing a tightly cropped image, the photographer creates an effect that somewhat anthropomorphises the scarab beetle. The strong diagonal contributes to the compositional success of the image.
For this project I chose for my subject the insects found on site at Loder’s Creek, Southport. I am currently preparing for a research trip to both Germany and then North Queensland that will require significant documentation of both fauna and flora and their interactions. I chose to shoot all images with my Canon EF100mm f/2.8 Macro IS USM Lens. The longer focal length of this lens, than my standard 24-70mm, greatly assists in creating a shallower depth of field. To achieve these images fast shutter speeds were required due to the speed in which the subjects might move. The ISO was adjusted as I shifted positions within the edges of the creek, into and out of the shadows. My aim was to find the ideal combination of ISO and low f-number (large aperture) to capture a high quality image in the low light conditions. By using only the two largest aperture settings possible with my macro lens, f/2.8 and f/3.2, I was able to successfully achieve high quality images with very shallow depth of fields.
When I first began to take photos I would quickly take a shot whenever I spotted an interesting insect. If I was lucky enough to have found a specimen happy to pose for more than a few seconds I was able to work quickly to shift the focus point and compose a better image in frame. I found this exercise to be very worthwhile in training my hand and brain to work very quickly together in manual mode to change shutter speed, apertures and focus point before an insect moved from their resting position on a plant. All of these images were taken on one summer morning between 7am and 8am. Having a specific outcome to work towards in a limited timeframe is a great exercise to undertake as it forces you to really focus on developing better camera skills. I found the process very personally rewarding and I feel so much for confidence in the use of my new camera and macro lens as a result.
My Final Images
This is one of my favourite images from the morning was this very pretty fly. I love the details captured by the camera in the fly’s eyes. Such wonderful patterns and colour caught on camera. The image is composed of the fly positioned on the 1/3 line vertically in frame. The rich purple black tones contrast well with the vivid green of the foliage. I was lucky enough to have this little creature give me enough time to think through composition whilst they rested on the leaf.
With my camera set at the widest aperture available on the macro lens I was able to capture amazing detail on this Asilidae resting on a branch in the shadows. I am astounded by the low light capabilities of the 5D Mark III combined with the 100mm Macro lens. Part of my passion for flies comes for the beautiful details, in both structure and colours, that can usually only be seen when examining a dead specimen under a stereomicroscope. To be able to capture the morphology of the insect so beautifully whilst alive is very exciting. It definitely makes it easier to convert others into seeing just how beautiful and under-rating many species of flies are! I was able to achieve an extremely shallow depth of field focusing on the facial features of the lacewing. The high shutter speed (1/640) and ISO were juggled in order to maintain clarity of the image at the correct exposure.
This was the supermodel of the day – a lacewing I suspect as I have not had a chance to identify it as yet from the other images I took showing the body in it’s entirety. He or she loved that leaf so much that they sat happily for about ten minutes and didn’t even budge when I shifted other foliage around them in order to get a better viewpoint. I chose this image out of the many taken because of the way in which selective focus has been effectively employed to create a sense of the possible personality of this creature. The softness of the background, the extremely shallow depth of field and the composition combine very effectively to anthropomorphises the insect.
I love the way in which the shallow depth of field has completely removed all details of the background leaving only two strong lines, one diagonal and one vertical, that create a very effective composition. I have included this image as it contextualises the animal’s scale against the blade of grass. This fly was in almost full sun which allowed me to maintain an ISO of 200 with a large aperture (f/3.2) resulting in a fairly high shutter speed that is not a disadvantage given my subjects in this project.