Moving Away From Auto Mode Level 2 © 2010 Cream Photo Workshops Version 240311

Out of the Box This workshop is for owners of Bridge & SLR cameras For those who want to go beyond the out of the box auto settings and take control of their cameras For those who see auto & program modes as a restriction on their creative talents

Quality images & creative control can be at your command if you master... The relationship between aperture, shutter speed & ISO Correct exposure

Creative Control Moving away from fully automatic or program modes allows you, the photographer, to be in control Control for the photographer means that they can use their camera more creatively

Using your camera off the fully automatic or program mode allows you to set three options to control the way it records the scene or subject: ISO Aperture Shutter speed All three are interrelated to create the correct exposure – change one and one of the other two must change to maintain correct exposure

ISO is the sensitivity to light of your camera’s sensor Typical ISO values are 100, 200, 400, 800 & 1600 Doubling the ISO value doubles the sensitivity of the sensor to light Reducing the ISO by half halves the sensitivity

High values of ISO my be required to take shots using low light levels and still be able to freeze motion Also to achieve adequate depth of field – what’s in focus in front & behind the point you focus on Nothing is free – as ISO values increase so does picture noise resulting in a loss of image resolution and sharpness

ISO 100

ISO 400

ISO 1600

We usually refer to shutter speeds as fractions of one second Shutter Speed – the time the shutter stays open to allow light through to the camera’s sensor We usually refer to shutter speeds as fractions of one second 1 1/2 1/4 1/8 1/15 1/30 1/60 1/125 1/250 1/500 1/1000

Portrait by Philippe Leroyer – Shutter Speed 1/8 Second Shutter speed is important because it controls how much movement of your subject is recorded Portrait by Philippe Leroyer – Shutter Speed 1/8 Second

A shutter speed of 1/500 or 1/1000 will freeze most fast motion Photo by Bryan Peterson

Shutter speed approximately 4 seconds For very long exposures use the B or Bulb setting Seascape by Orvaratli

Camera shake is the unintentional movement of a handheld camera during the exposure As a rule of thumb – don’t try to handhold your camera and use a shutter speed slower as a fraction of a second than the lens focal length in millimetres, e.g. don’t go below 1/100 second for a 100mm lens

Aperture – measured in ƒ-stops Just like the pupil in the human eye the aperture controls the amount of light entering the camera ƒ2.8 ƒ4 ƒ5.6 ƒ8 ƒ11 ƒ16 ƒ22

The lower the ƒ number the larger the aperture – the more light will be allowed through to the sensor in a given time The aperture also determines the depth of field – the region in front and behind the point of focus that also appears in focus The smaller the aperture (higher ƒ number) the greater the depth of field

ƒ2.8 ƒ11 ƒ22

ƒ22 ƒ11 ƒ2.8 What creative opportunities does the different aperture settings produce?

Wider apertures help to isolate your subject from the background & it works well with portraits At wide apertures (shallow depth of field) what you focus on is critical – it may require single point or manual focusing to get it right Frequently for portraits the most important thing to focus on is the subject’s eyes

If you change the ISO, shutter speed, or aperture, you must change one of the other two to maintain correct exposure If your camera is set to shutter or aperture priority you select the shutter speed or aperture and the camera’s light meter does the rest If you are on manual you will be in control of all three & have to adjust each to achieve correct exposure

With your camera on shutter or aperture priority keep a lookout in the viewfinder for flashing under or over exposure warnings In manual mode you may get no warnings – you are in total control Now we’ll produce a series of shots where you experiment with changing the ISO, shutter speed & aperture to creative effect

Correct Exposure Correct exposure is essential if you want to get the best quality images from your camera – automatic settings can get it wrong Computer technology allows us to adjust exposure levels at postproduction – but there are limits Images that have been ‘pulled’ at postproduction to correct exposure errors may look poor on screen and most certainly will NOT print well

To test how your camera’s exposure meter can get exposures wrong take a few shots using the fully automatic setting & JPEG files to do the following A person or object against a mid-tone background A person or object against a very light background A person or object against a very dark background

With a mid-tone background or one with an average distribution of light, dark & mid tones, the meter behaves as you would expect

With your subject against a dark background they come out too light – overexposed

Against a light background they’re too dark – underexposed Why is the camera meter getting it wrong?

Modern exposure meter design attempts to eliminate these errors but frequently the problem is still all too apparent Exposure meters are not intelligent – they can only do what they are calibrated to do Your camera makes an exposure by recording the light that’s reflected from the subject

Your camera’s exposure meter is calibrated to provide correct exposure for an average subject/scene An average subject/scene is one with a good distribution of tones, highlights to shadows, but mainly mid tones The meter is not intelligent and cannot know if your subject/scene has an excess of light or dark tones

The subject in front of the dark background comes out too light because overall the scene reflects less light than the average so the meter compensates by allowing more light in Equally the subject in front of a light background comes out too dark when the meter restricts the light entering the camera to bring it down to the average mid tone it’s calibrated for

You can intervene to prevent this Before we start you need to turn your camera’s mode selector (knob or menu) off a fully automatic or creative zone – sport, portrait, landscape etc. and select Program, Shutter Priority or Aperture Priority Leaving it on a fully automatic mode will probably not allow you to have any direct control over the way your camera behaves

To correct these exposure errors we have to tell the meter to allow less or more light into your camera than it would normally Most cameras will have a button similar to this that you hold while turning a selector wheel to dial in the correction

Your camera should allow you to override the exposure meter by +/- 2 or even 3 ƒ-stops Each time you go up a whole number (+ 1 ƒ-stop) you double the amount of light entering the camera Each time you go down a whole number (- 1 ƒ-stop) you half the amount of light entering the camera

No exposure compensation & our subject is too light against the dark background

By dialling in minus 2/3 ƒ-stops our subject is more accurately exposed

No exposure compensation & our subject is too dark against the light background

By dialling in plus 2/3 ƒ-stops our subject is more accurately exposed

Your camera’s exposure meter will frequently get the exposure wrong in the following situations Too light – when there’s an above average amount of dark areas in the frame – lots of dark foliage or rocks as a background

Too dark- when there’s lots of light areas in the frame – snow, on the beach, subject against a white painted wall, when the Sun is behind your subject producing a very bright sky The exposure meters in different makes and models of camera respond slightly differently – you will need to experiment to find how much exposure compensation you require in different situations

Using the LCD screen on your camera is not an accurate way to judge correct exposure – it appears dark in direct sunlight & bright in a darkened room On most bridge and SLR cameras you can view a histogram that shows the distribution of levels of brightness You can get an indication for the correct exposure by interpreting this histogram

The histogram of a correctly exposed scene with an average distribution of tones shows a central hump

The histogram of an underexposed shot or one with many dark tones is bunched to the left

The histogram of an overexposed shot or one with predominantly light tones is bunched to the right

Repeat the shots you did earlier but this time use exposure compensation and histogram to obtain a set of more accurate exposures Shoot a series of images using different degrees of correction so you can work out which ones work best with your camera

Sometimes you cannot take the risk of getting the exposure wrong If your subject is particularly dark or light it can be hard to judge just how much exposure compensation to give You can bracket – do a series of shots either side of the metered setting using exposure compensation – select the best afterwards

Use the exposure compensation control to do it manually -1 -2/3 -1/3 None Use the exposure compensation control to do it manually Some SLRs have an auto-bracket mode +1/3 +2/3 +1

Important After you have made any changes for exposure compensation or metering modes Remember – set your camera back to a more conventional or auto setting you are used to – it’s all too easy to forget

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