In this short guide you'll learn how to achieve professional-looking results using focal length, aperture and shutter speed...
1. Use the best focal length
If you use an APS-C camera like the Canon 80D or Nikon D3300, the best focal length for portraits is around 50mm. This is because for a classic head and shoulders composition, the distance you’ll need to stand from the model provides the most flattering perspective. To get the same composition with a wide focal length would mean moving much closer, producing an unflattering back-of-spoon look, as you can see from the images above. For full-frame users, the best focal length to use is 85mm.
2. Set a wide aperture to isolate your subject
Working in aperture-priority mode, choose your widest available aperture. On kit lenses this is around f/5.6, but with a 50mm prime you can open up to f/1.8. A wide aperture gives a shallow depth-of-field for a blurry background, helping the subject stand out. Set an ISO of 100 and the camera will balance the exposure with the correct shutter speed. In bright conditions, working at f/1.8 may prompt an exposure warning, in which case use a narrower aperture instead.
3. Watch your shutter speed
Given that indoor locations are considerably darker than outdoor ones, you’ll need to be more conscious of shutter speed. If it’s too slow, you won’t be able to hold your camera still enough to avoid camera shake, and you could end up with a blurred image. To be safe, keep your shutter speed faster than around 1/125sec by raising the ISO. You should also keep image stabilisation turned on if your lens has it. In the two comparison images to the left, you can see how a shutter speed that’s too slow has caused camera shake, but a much faster exposure of 1/200sec produces a pin-sharp result.
This article was first published in the June 2016 issue of Practical Photography - download back issues here.