Lens sizes Depth of Field Focal Lengths Lens sizes Depth of Field

Lens Sizes Camera lenses come in different sizes:

Lens Sizes The longer the lens the more it enlarges the object being photographed

Lens Sizes Lens are measured in mm… 50mm is roughly the same as what we see with the human eye:

Lens Sizes Less than 50mm (typically 24-30mm) gives wide angles:

Lens Sizes And more than 50mm (typically 70mm+) zooms in on a subject:

Zoom Lenses A zoom lens is a jack of all trades lens that can change its length from, say, 30mm to 70mm:

Crop Factor GEEK ALERT! Many digital cameras do not have a CCD sensor that is as big as a 35mm film frame so some cropping occurs

Depth of Field

Depth of Field Depth of Field (DOF) refers to how much of a photo is in focus Suppose you have focused on a person you want to photo:

Depth of Field The DOF is the distance you could move the object towards or away from the camera without having to re-focus:

Depth of Field Everything outside of this zone will be blurred and out of focus

Depth of Field >>> DEMO <<< >>>DOF with zoom lens<<<

Depth of Field There are three (four counting Photoshop) ways to create shallow Depth of Field: Use a long (70mm+) lens or a zoom Set a smaller aperture setting (f2.8 / f4) Put a Neutral Density filter on your lens

Aperture Settings There are various setting on an SLR camera: ISO Shutter Speed Aperture They all adjust different aspects of your photo…

Aperture Settings Aperture adjusts the Depth of Field by changing the size of the hole that light travels through to get to your film/CCD:

Aperture Settings Basically, the smaller you set the f number to, the smaller your Depth of Field:

Aperture Settings

Aperture Settings Changing the aperture means changing the shutter speed to compensate (more next week), for now… Set your camera to aperture priority mode (usually marked ‘A’ or ‘Av’on the control dial)

Compact Cameras & Phones Narrow DOF Wide DOF

>>> TASK <<< Depth of Field >>> TASK <<< Put an a few objects on along a table Step back as far as you can and zoom in to create DOF Then get closer and take two identical photos – one on f2.8 and one on f16 If you don’t have these setting on your camera try using Macro mode and getting really in close… …and/or take some photos that you can add DOF to later using Photoshop

And Finally… ND Filters On a bright summer’s day you will have to set your aperture to a high number (f11 / f16) to avoid over exposure… So setting a small f-number to get a small Depth of Field will not work The solution is to put a Neutral Density filter on your camera…

Neutral Density Filters Using an ND filter is a bit like putting sunglasses on your camera

Neutral Density Filters What this means is that you can open the aperture a bit more and get more Depth of Field ND filters do not effect the colour, only the amount of light reaching the film/CCD

Photoshop And, of course, Depth of Field can be faked using Photoshop selections and a blur filter:

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