PHOTO SKILLS: DEPTH- OF- FIELD
What Are the four factors that influence depth- of- field? seasoned Photographers should be Able to Answer this With ease, but if you’re A novice read on, As caroline schmidt tells you What you’ve been missing And how to dramatically improve your Portrait
It’s just about aperture, isn’t it? Wrong! Learn how to alter and control depth- of- field to improve your portraits
If you’re new to digital SLR photography, you’ve likely made the jump from a more basic camera because you want more control, better image quality and the beautiful smooth bokeh that’s inherent with shallow depth- of- field. The former will take practice to achieve but the latter isn’t just the product of your tools, this too takes technique and know- how to master. Most beginners think depth- of- field is controlled only by your aperture: the wider the aperture, the bigger the bokeh, and while this is true, the nuances of depth- of- field are a little more complex.
So what are the other factors you’re forgetting? focal length, subject- tobackground distance as well as camera- to- subject distance. once you know how to play with all four factors, you will quickly see an improvement in your portraits and places to shoot.
Lets talk about lenses for a moment. Lens type and focal length all affect the behaviour of shallow depth- of- field. A 35mm provides more apprarent depth- of- field at the same aperture than, say, a 50mm or a telephoto lens like a 70- 200mm, which compresses perspective. The most flattering focal range for portraits, however, is 50mm to 85mm hence why the ‘ nifty fifty’ f/ 1.8 is a popular choice for portraits. whatever the focal length, however, as a general rule of thumb, depth- of- field falls approximately 1/ 3 in front of a point of focus and 2/ 3 behind it.
once you understand how to control shallow depth- of- field, you have the tools to make almost any backdrop or cluttered shooting condition work. while backgrounds without distractions are preferable, sometimes vibrant colour and texture can be very effective for adding interest and impact when rendered as gorgeous smooth blur. Let’s show you what we mean…
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& set tings Barn walls and outbuildings can make for very interesting, colourful backgrounds and often provide spots of open shade for soft, flattering light and saturated colours – if you find any, make use of them! While blurring the background is important for drawing focus on the subject’s face, it’s not worth potentially compromising on the sharp focus of your subject by using an extremely wide aperture. Unless there is considerable distance between you and your subject, step your lens down to at least f/ 2.5 to extend your plane of focus and use other means to enhance bokeh. All these images were shot at f/ 3.5 on an 85mm f/ 1.4G lens. The only variable is the distance...
t Ypic Al start Most beginners initially compose a headshot by placing the subject next to, or less than a foot away, from the background and then stand themselves 3- 5ft away. At these distances you may get a nice crop, but as depth- of- field extends approximately 2/ 3 behind the subject, a fair amount of distracting detail appears relatively sharp, which is not what we want.
subject further AWAY By moving the model about 6ft from the background, and remaining approximately 5ft away from them, depth- of- field looks much shallower due to the extended background- to- subject distance. The backdrop now falls outside the remit of acceptable sharpness, but we can do better still by moving the subject even further away from the building.
move closer Depending on your focal length, generally the closer the camera is to the subject, the shallower the depthof- field will be. So by increasing the subject- to- background distance to 10ft and moving in for a closer crop, I capture a softer focus of the subject’s face and render the background a vibrant blur of colour with enhancing but not distracting texture.
if i Want A Wider crop? As depth- of- field extends twice as far behind the point of focus as it does ahead of it, if you stand, say, 10ft away you’ll find an aperture that captures all your subject in focus will record detail in the background if they’re too close to it. As a rule of thumb, double – even triple – your subject- tobackground distance compared to your camera- to- subject range.