Exercise 2.3: Focus

Brief

Find a location with good light for a portrait shot. Place your subject some distance in front of a simple background and select a wide aperture together with a moderately long focal length such as 100mm on a 35mm full-frame camera (about 65mm on a cropped-frame camera). Take a viewpoint about one and a half metres from your subject, allowing you to compose a headshot comfortably within the frame. Focus on the eyes and take the shot. 

Wide apertures create shallow depth of field, especially when combined with a long focal length and a close viewpoint. In human vision the eye registers out-of-focus areas as vague or indistinct – we can’t look directly at the blur. But in a photograph, areas of soft focus can form a large part of the image surface so they need to be handled with just as much care as the main subject. 

Don’t forget that the camera’s viewfinder image is obtained at maximum aperture for maximum brightness and therefore at the shallowest depth of field. Use the depth of field preview button to see the actual depth of field at any particular aperture. It’s surprising to see the effect that a single f stop can have on the appearance of an image. 

Execution

I attempted this shot a few times in the late evening sun just before it set, at a few places in my house where one gets natural sunlight. I have arranged the shots in the sequence of my liking them, keeping in mind how the background can add or take away from the image.

In Image 1 the subject is indoors and the face is being lit by the natural light filtering in though the doorway. I like the background in this image as it adds just a bit of a contrast while still being subtle, with just the right balance to set the foreground away from the background. The light upon the face creates a bright contrast even though the background is dark.

Camera Settings

• Nikon D5
• Nikkor 70-200mm f2.8
• ISO 100
• Aperture Priority Mode
• Exposure – underexposed by 1/3 of an f-stop
• f2.8
• Shutter 1/320s
• @95mm

In Image 2 above, I have placed my subject indoors, slightly away from a simple backdrop of a wall, where the sunlight falls creating an interesting play of light and shadows. Despite the relatively flat background, the light falling on the wall creates an interesting background on a flat wall, thereby giving the image a balanced appearance.

• Nikon D5
• Nikkor 70-200mm f2.8
• ISO 100
• Aperture Priority Mode
• Exposure – underexposed by 1/3 of an f-stop
• f2.8
• Shutter 1/320s
• @140mm

In Image 3, I have placed my subject slightly away from a simple backdrop of a wall, exactly as in Image 2, but this time the set up is taken outdoors as opposed to the second image. The sunlight falling on the face lights the subject well, but the wall behind is not working as well as in the earlier shot, giving a relatively flat appearance to the image.

• Nikon D5
• Nikkor 70-200mm f2.8
• ISO 100
• Aperture Priority Mode
• Exposure – underexposed by 2/3 of an f-stop
• f2.8
• Shutter 1/500s
• @105mm

In Image 4, I have placed my subject outdoors again, against a green backdrop of plants. Though the subject is well exposed and in focus, this is my least favourite frame as the canopy above is creating a distraction in the frame.

• Nikon D5
• Nikkor 70-200mm f2.8
• ISO 100
• Aperture Priority Mode
• Exposure – underexposed by 2/3 of an f-stop
• f2.8
• Shutter 1/500s
• @86mm

In order to understand what the aperture does with a single change in the f-stop, I have taken a series of images with different f-stops to see what happens to the background. The results are as follows. You can enlarge any image by clicking on it. Th f/stop and shutter speed is written under each image. The other camera details are:

• Nikon D5
• Nikkor 70-200mm f2.8
• ISO 80
• Aperture Priority Mode
• Exposure – underexposed by 2/3 of an f-stop

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As can be seen, there is a difference with each f/stop – the wider the aperture the shallower the depth of field and the narrower the aperture the larger the depth of field. In the first image with the f/stop of 2.8 the background is out of focus and in the last image with the f/stop of 16 the background is much more in focus. This can help us in applying informed decisions and create images accordingly.

Learning Outcomes

• How to create a shallow vs. larger depth of field.
• How shallow depth of field helps guide the viewer’s eye to the focus area of your subject, by blurring the background.
• To create interesting bokeh or a blur to your frame in order to create interesting compositions.
• To create desired depth within a photograph simply.
• To compose a shot avoiding distracting backgrounds, even if they are not in focus.
• To create good portraits effectively by controlling the light that comes into the camera by identifying the correct combination of focal length, ISO, shutter-speed and distance from the subject.
• Importance of negative and positive spaces within a frame is equally important.
• Understanding f/stops and how to establish a desired relationship between the foreground and background using them effectively.