68 | EOS magazine April-June 2019

Auto Lighting Optimizer (ALO) is an effective camera feature. It analyses images and modifies shadows and highlights to minimise loss of detail in high contrast lighting conditions. The effect can be subtle or strong, depending on the lighting and the subject.

Light optimiser

Auto Lighting Optimizer has brightened the dark façade of the building, while the lighter areas of the image remain largely unchanged. EOS 6D Mark II, EF 24-105mm f4L IS USM lens at 28mm, 1/500 second at f11, ISO 400.

CAMERA FUNCTION Auto Lighting Optimizer

Auto Lighting Optimizer (ALO) was introduced on the EOS 450D in 2008 and is found on all current EOS cameras. ALO provides in-camera processing to improve your images. ALO evens out contrast by selectively adjusting areas of the image. It is especially useful with flash or backlit subjects as it can detect faces in the frame and brighten those areas to achieve a better result.

Underexposed picturesIf the image is underexposed, Auto Lighting Optimizer boosts the contrast slightly and lifts the darker areas of the image to give a better result. The brighter areas of the image change much less than the darker parts. With an image taken on a bright day the effect is not as dramatic, but it nevertheless prevents the shadow areas in the image going too dark. ALO can reduce the need to use exposure compensation to lighten the darker parts of the image as it will do this automatically. As a result, ALO retains better exposure for the highlight areas of the image.

Backlit exposuresWhen shooting backlit subjects, having Auto Lighting Optimizer activated can help the exposure. Portraits nearly always show an improvement (the effect is clearly visible in the example on the opposite page). Heavily backlit scenes also benefit, though the difference is usually more subtle than in portraits. With wildlife images, when using long telephoto lenses the effect is negligible, even if shooting with heavy backlighting. EOS cameras use artificial intelligence to decide whether to correct the image, and by how much. This is why ALO is a feature that can safely be left turned on most of the time for most types of photography. However, if you specialise in the more complex types of portraiture where you are after specific techniques, such as low key, it can overdo the amount of correction. Try shooting with and without ALO to see the difference. With experience, you will know when to turn Auto Lighting Optimizer off.

BRIAN

WO

RLEY

NIN

A BA

ILEY

Auto Lighting Optimizer OFF

Auto Lighting Optimizer STRONGAuto Lighting Optimizer STANDARD

Auto Lighting Optimizer LOW

The model’s face in this backlit portrait has been lightened by using Auto Lighting Optimizer at its strongest setting. EOS R, EF 100mm f2.8L Macro IS USM lens, 1/500 second at f3.5, ISO 320.

ALO settingsTo show the effect of ALO in this article we have used comparison images with ALO OFF and ALO Strong settings, so that the difference is more easily discernible, even given the limitations of magazine printing. We recommend you use the Standard setting.

Exposure comp.If ALO is set to Enable (or Low, Standard or Strong) and you use exposure compensation or flash exposure compensation to darken the image, the result might be brighter than you want. This is because ALO tries to cancel out the compensation. For a darker image, use exposure compensation with ALO set to Disable (or OFF).

EOS magazine April-June 2019 | 69

Auto Lighting Optimizer STRONG

Auto Lighting Optimizer OFF

70 | EOS magazine April-June 2019

CAMERA FUNCTION Auto Lighting Optimizer

Auto Lighting Optimizer at work

Hazy and misty scenesHazy or misty days can produce flat images. Auto Lighting Optimizer will help to increase the contrast in the scene and this will often help to improve the result. That said, if the scene is particularly hazy or misty, although ALO will boost the contrast, the scene will still look misty and slightly flat. This is the most subtle of the ALO effects and does not always show such a significant improvement compared to the other effects – as the images to the right confirm. ALO has more impact on such scenes now than when it was first introduced, but it can still be very subtle, making it difficult to distinguish between the different ALO strength settings. However, it does no harm to leave Auto Lighting Optimizer active for these types of scenes.

Underexposed flash scenesAuto Lighting Optimizer usually makes a significant difference when you are shooting with fill-in flash. Flash works well when shooting backlit subjects or in very strong lighting outdoors. However, it is common for the automatic fill-in flash reduction to decrease the flash a little too much and produce what appears to be a slightly underexposed result. With Auto Lighting Optimizer turned on, the camera will lighten the face to provide a better overall exposure for the image. This works especially well if shooting with built-in flash or with a Speedlite fitted to the hotshoe of the camera and used without any reflector or diffuser. If shooting in lower light levels or using a more sophisticated flash set-up, Auto Lighting Optimizer may not be needed, and can sometimes work against the effect you are trying to achieve.

Auto Lighting Optimiser has little effect with hazy and misty scenes. EOS 6D Mark II, EF 70-300mm f4-5.6 IS II USM lens at 155mm, 1/250 second at f16, ISO 1000.

Auto Lighting Optimizer is effective when using flash in bright daylight. High speed flash synchronisation (using a Speedlite 580EX) has been set to enable a fast shutter speed, which is suited to this daylight exposure. EOS 5D Mark IV, EF 24-105mm f4L IS II USM lens at 85mm, 1/3200 second at f5, ISO 400.

Auto Lighting Optimizer is less effective with flash photography in low light, nevertheless the effect is still easily visible in these portraits. EOS 5D Mark IV, EF 85mm f1.8 USM lens, 1/200 second at f4, ISO 400, off-camera Speedlite.

NIN

A BA

ILEYBRIA

N W

ORLEY

NIN

A BA

ILEY

Auto Lighting Optimizer OFF Auto Lighting Optimizer STRONG

Auto Lighting Optimizer OFF

Auto Lighting Optimizer STRONG

Auto Lighting Optimizer OFF Auto Lighting Optimizer STRONG

EOS magazine April-June 2019 | 71

Setting Auto Lighting Optimizer

Pressing the Q button, if available, displays the Quick Control Screen.

Most EOS cameras use icons to represent the Auto Lighting Optimizer settings. OFF, not surprisingly, indicates that the feature is disabled.

One solid bar (left) represents the Low setting. This is the weakest option available – do not expect to see much difference from the OFF setting.

The Standard option is shown by two solid bars (left). This is the default setting on most models. You will need to turn it off if you do not want to use Auto Lighting Optimizer.

The final setting – Strong – is represented by three solid bars (left). Use this for the maximum effect.

On most models with Auto Lighting Optimizer, it is easiest to set the function from the Q screen. If you select the function icon and press the SET button (or tap a screen with touch control) it will bring up the four options that are available. It will also show you the ‘Disabled in M and B modes’ check box, if available. ALO is disabled by default in these modes, but on some cameras it can be enabled. Auto Lighting Optimizer can also be set via the shooting (red) camera menu if you prefer. On mirrorless models, when using the rear LCD screen, you can access the ALO option by pressing the Q button. The options are displayed superimposed over the image. When the ALO icon is selected, the strength options are displayed along the bottom of the screen. The ‘Disabled in M or B modes’ option is controlled by the INFO button on most models, but can also be set using the touch controls if your camera has them. Similar ALO options can be used on most of the DSLR models if the Live View screen is active and the Q button is pressed, though the way that the choices are arranged varies according to the age of the camera.

RAW images and ALOIf you are shooting RAW files, does it matter what options you set on the camera? After all, it is possible to change or even disable the Auto Lighting Optimizer setting if processing the RAW image in Digital Photo Professional (DPP) software (see page 74). However, it is important to realise that, even when shooting in RAW, the preview of the image provided by your camera still includes all the settings on the camera at the time of shooting – so the preview image (and its histogram) will show the effect of the image with ALO set. This also applies to any highlight alert warnings. Turning ALO off may make you think that the image is not correctly exposed and lead you to apply corrections that are not actually necessary.

JPEG images and ALOIf you shoot JPEG images, Auto Lighting Optimizer will give you improved images most of the time. Applying corrections at the time of shooting means you do not have to apply them later. Once you have taken the photograph you can see the effect in the image review and, if the results are not what you want, you can turn ALO off. With the advent of mirrorless EOS models, especially the new EOS R and RP cameras with their much improved electronic viewfinders, you see the image with all the corrections applied either on the rear screen or in the viewfinder. You can see the impact of Auto Lighting Optimizer (and the other image processing options) before shooting and can decide whether to leave them set as they are, or make changes to capture an image which better meets your requirements.

Selecting the ALO icon brings up the options – OFF, Low, Standard and Strong.

You can also access Auto Lighting Optimizer through the Shooting menu.

Some cameras allow you to enable ALO in ‘M’ and ‘B’ modes (disabled by default).

In early EOS cameras, ALO is a Custom Function (see table on page 73).

Pressing the Q button in Live View on current models presents this display.

This is the display in Live View mode on older EOS cameras.

72 | EOS magazine April-June 2019

CAMERA FUNCTION Auto Lighting Optimizer

Auto Lighting Optimizer and Highlight tone priority

ALO is greyed outAuto Lighting Optimizer can be greyed out if certain other camera options are enabled. The main feature that affects it is Highlight tone priority (found either in the shooting menu or within the Custom Functions). If this is set, D+ appears by the ISO setting on the

Highlight tone priorityHighlight tone priority can be useful if you often photograph subjects that are white – for example, if you are a wedding photographer. However, this feature is often left set to Enable, which can have an adverse effects on other images you are taking. Auto Lighting Optimizer will be disabled, and so backlit subjects will not benefit from the corrections described in this article. Highlight tone priority can also cause problems for fill-in flash images, especially those taken with built-in flash or on-camera flashguns, resulting in quite dark images if taken in backlit conditions.

Q screen on the rear of the camera (above right). Highlight tone priority is designed to give better highlight details at the expense of the dark and shadow areas of the image. It is doing the exact opposite of Auto Lighting Optimizer, so the two cannot work together.

Other features that disable ALOAnother feature which disables the Auto Lighting Optimizer is HDR mode or High Dynamic Range (below left). This is designed to widen the dynamic range of an image by taking three shots of the same scene at different exposures and then combining them into a single image. Setting ‘Multiple exposure’ (below right) will also disable ALO.

Auto Lighting Optimizer STANDARD Highlight tone priority ENABLED

NIN

A BA

ILEY

EOS 550D, EF-S 17-85mm f4-5.6 IS USM lens at 85mm, 1/1600 second at f5.6, ISO 200.

EOS 550D, EF-S 17-85mm f4-5.6 IS USM lens at 85mm,, 1/1600 second at f5.6, ISO 200.

EOS magazine April-June 2019 | 73

Camera listWhere ALO is set Number of options

EOS-1D Mark IV CF II - 4 4 optionsEOS-1D X Q screen/Shoot menu 4 options. Off in M/BEOS-1D X Mark II Q screen 4 options. Off in M/BEOS 5D Mark II CF II - 4 4 optionsEOS 5D Mark III Q screen/Shoot menu 4 options. Off in M/BEOS 5D Mark IV Q screen/Shoot menu 4 options. Off in M/BEOS 5DS Q screen/Shoot menu 4 options. Off in M/BEOS 5DS R Q screen/Shoot menu 4 options. Off in M/BEOS 6D Q screen/Shoot menu 4 options. Off in M/BEOS 6D Mark II Q screen/Shoot menu 4 options. Off in M/BEOS 7D Q screen/Shoot menu 4 optionsEOS 7D Mark II Q screen/Shoot menu 4 options. Off in M/BEOS 50D CF II - 4 4 optionsEOS 60D Q screen/Shoot menu 4 optionsEOS 70D Q screen/Shoot menu 4 options. Off in M/BEOS 77D Q screen/Shoot menu 4 options. Off in M/BEOS 80D Q screen/Shoot menu 4 options. Off in M/BEOS 100D/Rebel SL1 Q screen/Shoot menu 4 options. Off in M/BEOS 200D/Rebel SL2 Q screen/Shoot menu 4 options. Off in M/BEOS 450D/Rebel XSi CF II - 4 2 optionsEOS 500D/Rebel T1i Q screen/Shoot menu 4 optionsEOS 550D/Rebel T2i Q screen/Shoot menu 4 optionsEOS 600D/Rebel T3i Q screen/Shoot menu 4 optionsEOS 650D/Rebel T4i Q screen/Shoot menu 4 options. Off in M/BEOS 700D/Rebel T5i Q screen/Shoot menu 4 options. Off in M/BEOS 750D/Rebel T6i Q screen/Shoot menu 4 options. Off in M/BEOS 760D/Rebel T6s Q screen/Shoot menu 4 options. Off in M/BEOS 800D/Rebel T7i Q screen/Shoot menu 4 options. Off in M/BEOS 1000D/Rebel XS CF II - 4 2 optionsEOS 1100D/Rebel T3 Q screen/Shoot menu 4 optionsEOS 1200D/Rebel T5 Q screen/Shoot menu 4 optionsEOS 1300D/Rebel T6 Q screen/Shoot menu 4 optionsEOS 2000D/Rebel T7 Q screen/Shoot menu 4 optionsEOS 4000D/Rebel T100 Q screen/Shoot menu 4 optionsEOS M Q screen/Shoot menu 4 options. Off in M/BEOS M2 Q screen/Shoot menu 4 options. Off in M/BEOS M3 Q screen/Shoot menu 4 options. Off in M/BEOS M5 Q screen/Shoot menu 4 options. Off in M/BEOS M6 Q screen/Shoot menu 4 options. Off in M/BEOS M10 Q screen/Shoot menu 4 options. Off in M/BEOS M50 Q screen/Shoot menu 4 options. Off in M/BEOS M100 Q screen/Shoot menu 4 options. Off in M/BEOS R Q screen/Shoot menu 4 options. Off in M/BEOS RP Q screen/Shoot menu 4 options. Off in M/B

The Auto Lighting Optimizer (ALO) function was first seen on the EOS 450D in 2008 and has been featured on every EOS model since. Initially found within the Custom Function settings, it was a simple ‘Enable’ or ‘Disable’ option. Then, with the introduction of the EOS 50D and 5D Mark II later the same year, new options were added – a default of ‘Standard’, plus ‘Low’, ‘Strong’ and ‘OFF’. The introduction of the EOS 7D in 2009 saw the function moved to the Quick screen on the rear of the camera – still with the four options and set to ‘Standard’ as a default. It has remained much the same on later models One addition is a check box that is ticked by default to disable ALO in manual (M) and bulb (B) modes. (Off in M/B in table above). Unticking the box allows ALO to be used in these modes.

Photoshop and Auto Lighting OptimizerThe portrait below was shot in RAW with Auto Lighting Optimizer set to Standard. This camera setting, along with others, is saved to a metafile, which is attached to the RAW file. The image below left is from the RAW file opened in Canon’s Digital Photo Professional (DPP). This software reads the metafile and opens the image with the camera settings applied. However, if you do not like the result you can change the setting, or apply a setting that was switched off on the camera at the time of shooting. The image below right is from the same RAW file, but it has been opened using Adobe Photoshop. The image is disappointing compared to the result from DPP. This is because third-party software cannot use the camera information in the metafile attached to the RAW file – Canon protects its technology and image processing algorithms with patents. Of course, with a little post-processing, the Photoshop image could be made to look like the DPP image, but that is adding to your workflow. If you would prefer to spend time taking photographs rather than processing them, give DPP a go.

When the Auto Lighting Optimizer function first appeared on EOS models it was considerably less sophisticated than it is on recent models. The EOS 450D simply had an ‘ON’ or ‘OFF’ option. The choice of four options was first introduced on the EOS 50D and 5D Mark II. On both of these models Auto Lighting Optimizer is set to Standard as a default – the same as all current EOS cameras. On early models, ALO really only affected portrait images as it looked for subjects usually shot at this type of distance. Even then, its effects were far more subtle than what is now possible. These changes in the way ALO and other camera features work are ongoing and are one of the reasons why you can see so much difference in the image quality if you upgrade to one of the latest models. It was in 2012, with the introduction of the EOS 5D Mark III, 6D and 650D, that we really start to see the full effects described in this article. A good indicator is the type of DIGIC processor in the camera. DIGIC 5 and later offer the better Auto Lighting Optimizer options. Interestingly, there are still models in the current line-up that use the older DIGIC 4+ processor – including the EOS 4000D, 2000D and 1300D – which helps to keep costs down to a budget level.

Differences between EOS models

Digital Photo Professional Adobe Photoshop

NIN

A BA

ILEY

74 | EOS magazine April-June 2019

Auto Lighting Optimizer in Digital Photo Professional

CAMERA FUNCTION Auto Lighting Optimizer

A question frequently asked about Auto Lighting Optimizer is “Will it mess up subjects such as sunsets?”. In most instances, there seems to be little effect on a sunset, especially if the sun is in the image and the exposure is set for the sky. On a pre-sunrise image (above) where there is less contrast in the scene and hence slightly more shadow detail, there is a slight difference in the two comparison images with Auto

Lighting Optimizer set to ‘Off’ and ‘Standard’, but it is difficult to see without looking at the two images together. The image taken on the ‘Standard’ setting shows more shadow detail but there are no shadow areas that are too bright. It all comes down to the clever way that Canon has programmed Auto Lighting Optimizer and how it is able to recognise the type of subject being shot.

Auto Lighting Optimizer STANDARDAuto Lighting Optimizer OFF

The in-camera options for Auto Lighting Optimizer are also available for RAW files when using Canon’s Digital Photo Professional software. Unusually, the ALO option is found in two different places in the software. It can be accessed from the ‘Perform basic image management’ tab (right) in the Tool palette. It can also be set from the ‘Tone curve adjustment’ tab (far right). In both cases, click on the tick box to activate ALO (highlighted with the red box). The setting options are the same for both methods. The settings in DPP are the same as on the camera – Off, Low, Standard and Strong. The effect of the options are displayed immediately on the image being edited.

Before and after previewIf you are not sure if ALO is beneficial to your image, open a RAW file and then bring up the with and without preview by clicking on the icon below the image (circled bottom right). The original image always opens on the left, and in this case it was taken with the default setting of Standard ALO applied. Any changes made using the Tool palette are reflected in image on the right, while the image on the left remains unchanged. The image on the right has ALO turned off (see the red highlighted box), and you can see that the shadows are darker than the original image on the left. When the image is opened it displays with the settings that were on the camera at the time of shooting. However, with a RAW file, all of these settings can be adjusted in DPP, not just ALO.

Will Auto Lighting Optimizer ruin sunset images?

NIN

A BA

ILEY

Screens from DPP version 4

Join EOS magazine for the best in-depth information and inspiration for your Canon EOS photography, delivered direct to your door

Exclusive to EOS cameras Essential for EOS users

Visit www.eos-magazine.comor call 01869 331741

April to June 2018

Backlit portraitsHow to separate your subject from the backgroundZooming close How close can you focus with a zoom lens?Expanded ISO settingsHow and when to use these extreme values

DEDICATED TO CANON EOS CAMERAS

CELEBRATING 25 YEARS OF EOS MAGAZINE – EXPLORING EOS PHOTOGRAPHY SINCE 1993

NEW PRODUCTSEOS M50EOS 2000DEOS 4000DSpeedlite 470EX-AI

100 issue

th

Get five issues for only £19.95* with offer code PORTRAIT20

Extra issue free

Join today and get• Five issues for four in your first year• Exclusive EOS system guide to download• Subscriber-only offers• Expert technical advice by phone and email• Money-back guarantee if you’re not satisfied

Save 20%

We know the EOS system inside out, meaning that every article will give you the information you need to get the most out of your Canon camera.

Every image is shot using Canon gear. We’ll explain the techniques used and show you how you can recreate them with your existing EOS equipment.

EOS magazine will inform you

EOS magazine will inspire you

*£19.95 is discounted UK rate. Standard rates: UK £24.95, International £32.95