Capture: Portraits and Depth of Field

By decreasing the ‘depth of field’ of a head and shoulders portrait we are drawn into the subject’s eyes (the windows to the soul). These portraits are often very powerful and possess qualities that cannot be achieved with smart phones and compact cameras. Any distractions in the background are lost in the out-of-focus blur.

Depth of Field (the zone of sharp focus) decreases as the size of your lens aperture increases (smaller f numbers) and also decreases as the size of the sensor increases (cameras with full-frame sensors capture less depth of field compared to cameras with APS-C sensors at the same aperture). Owners of Alpha cameras with APS-C sensors and kit lenses can find it difficult to recreate the shallow depth of field look.

One factor often overlooked, however, is that depth of field also decreases as you move closer to your subject. Don’t be afraid when framing a horizontal composition to crop into the top of the head. Framing wide and then cropping in post will increase your depth of field.

If you are an owner of an APS-C camera such as the A5000, A5100 or A6000 and want to achieve even less depth of field check out the SEL50F1.8 prime lens (for APS-C E-Mount). This is one of Sony’s most affordable lenses, has a bright f/1.8 aperture and produces very sharp images.

F2.8 shallow depth of field
F2.8 shallow depth of field

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When working with very large apertures, such as f/2.8 or wider, at close range the photographer must be careful to ensure the eyes are sharp as the zone of sharp focus is very narrow. In the image below I have zoomed in to show how the autofocus has picked up the hair instead of the eye, leading to soft focus on the eye. Sony Alpha owners have several tools at their disposal to ensure sharp focus is placed on the eye. These include Focus Magnify, AF Assist and Eye-AF.

When using the A7RII and A6300. Eye-AF can be used in conjunction with AF-C (Continuous Auto Focus).

I have created a mini-course, that can be found in the Capture section this community site, to guide your through the craft of capturing fabulous portraits.

http://www.markgaler.com/product/sony-alpha-portrait-photography-mini-course

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The image above was captured with a Sony A7RII camera using the SEL50F1.4 lens at an aperture of f/2. The range of Sony f/1.8 and f/1.4 lenses are great to separate figure from background when you are creating 1/2 and 3/4 length portraits.