Finding the optimum exposure for your subject requires balancing technical considerations and creative intent to arrive at an exposure that best portrays your subject. Here is what you need to know.

Exposure can be tricky as it has technical considerations and is also subjective depending on the photographer’s intentions when portraying a subject. Camera meters look to balance out the brightness range of a scene from the darkest element to the brightest. As photographers, we need to expose the scene based on the lighting and our photographic intent.

• Understanding the Exposure triangle: The exposure triangle relates to the relationship between aperture, shutter-speed and ISO.
  • Aperture: Pertains to the amount of light coming through the lens. Small apertures (large F-stops) let less light in, Large apertures (small F-stops) let more light in.
  • Shutter-speed: Shutter-speed regulates how long a camera sensor or analogue film is expsoed to the light coming through the lens.
  • ISO: ISO sets the relative sensitivity of the camera’s image sensor to light, with analogue film photography, film has a ‘given ISO’ that cannot be changed. Lower ISO settings provide cleaner images and in digital photography low ISO settings also help render more detail from the shadows to the highlights (dynamic range). Higher ISO settings are used in low-light environments to boost shutter speed and aperture settings. Higher ISO settings can also be helpful when you need to use fast shutter speeds for action photography.
• Metering: The brightness of a scene is measured by the camera’s built-in lightmeter and the camera sets a base exposure according to the camera mode in use.
• Histogram: Camera Histograms show the distribution of tones in an image and help you assess exposure, darker tones are to the left, brighter tones to the right and mid-tones are in the middle of the histogram. Histograms can help warn of over or underexposure or when the brightness range of a scene exceeds the dynamic range of a camera sensor.
• Exposure compensation: When using full auto or semi-auto modes, exposure compensation allows you to adjust your exposure by decreasing or increasing the exposure value suggested by the camera’s meter. This is useful in tricky lighting situations or when the recommended exposure value does not work for your subject.
• Bracketing: In difficult lighting conditions or when the brightness range of the scene is beyond the dynamic range of your camera (you can check this by referring to your histogram) bracket your exposures, you can choose the best image later or combine images into an HDR shot.
• Manual mode: Manual mode gives you complete control over the aperture, shutter speed and ISO to control exposure. A built-in light meter or an external light meter is needed to meter the subject and lighting and then you set the ISO, aperture and shutter speed

Below is a before and after image, this is image was shot in manual mode and under exposed to retain detail in the brightest parts of the scene, it was saved as a RAW file for post processing.

Finding the optimum exposure for your subject requires balancing technical considerations and creative intent to arrive at an exposure that best portrays your subject!

Exposure Triangle and Exposure Values

Many people starting out in photography get confused by the relationship between aperture, shutter speed and ISO. Commonly known as the exposure triangle.

I think that one reason why photographers struggle with the exposure triangle, is that, nobody talk about EV, Exposure Value(s).

The exposure triangle refers to the relationship between aperture, shutter speed and ISO when metering, and photographing a subject or scene.

EV is determined by your camera’s meter or by a hand-held meter and is based on the overall brightness of a scene or subject, it is expressed as a number. Although, you never get to see this number with most modern digital cameras.

To help you understand more about the exposure triangle, here is an image of a Sekonic L-208 TWINMATE Analog Light Meter, you can see that at ISO 100 and an EV of 5.5, the light meter shows the combination of aperture and shutter speeds that can be used to obtain a correct exposure. This is important to understand and explains how your camera’s light meter, ISO and combination of aperture / shutter speed work together to create produce an exposure.

EV Scale

Bright scenes have higher numbers 15-20 or more, dark scenes have low numbers which might even be as low as -6 to 0.

So we can have arrange of exposure values from -6 or less, through 20 or more.

EV’s -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 1 5 16 17 18 19 20

Darkest——————————————————————————–Brightest

When you meter a scene, your camera meter assigns the scene an exposure value, and depending the shooting mode set on your camera, you or the camera will do the following:

Because there is a correlation between aperture and shutter speed for any given EV, there are number of aperture / shutter speed combinations you can use when determining your exposure.

(If you refer back to the image of the Sekonic light meter above, you can see the combination of aperture and shutter speeds that can be used @ ISO 100 and an EV value of 5.5.)

ISO

In the days of analogue film, if you were shooting in low light, you would buy a film that had a higher ISO rating, making it more sensitive to the light and enabling you to ensure that you could expose the scene properly.

In principle, with digital cameras, ISO functions in much the same way. However, the main benefit of being able to adjust ISO is that it can help you

• Keep the noise in your images as low as practical.
• Use the appropriate aperture / shutter speed for your subject in various lighting conditions by raising or lowering your ISO.
• Avoid under or over exposed (usually the former) images when the scene is too dark or too bright for your chosen aperture / shutter speed combination.

Back to EV,s and the Exposure Triangle

Understanding the concept of Exposure Values (EVs) when metering a scene, helps you make sense of the exposure triangle and how to use each element of the exposure triangle to your advantage when using your camera.

The arguments around shooting JPEG or RAW are less clear as cameras become more sophisticated and more capable in processing RAW data. Todays cameras produce excellent results when processing RAW data into a JPEG image that is saved on your camera’s memory card.

An often heard argument from photographers, is that “RAW files contain more data than JPEG files and therefore in terms of post processing your images, you should shoot RAW, but this is not really correct!

Yes, RAW files have more data than a JPEG file but that is because a JPEG file has already been processed. You cannot process a JPEG file, you may edit it to a certain degree but not process it.

The diagram below shows the basic workflow from taking an image to processing it. The key-point in terms of processing the RAW data is that you either let your camera processor do it and save the file as a JPEG, or you save the RAW data to a RAW file and process the RAW file with your preferred image editing software.

RAW files provide you with more flexibility when choosing how to process your images and you set or apply the following edits according to your taste.

• White Balance.
• Brightness.
• Contrast.
• Sharpening.
• Highlight / Shadow recovery.
• Noise reduction.
• Converting to JPG, DNG, TIFF.

With JPEG files all of these edits are applied when the RAW data is processed, they are based on your camera settings and can include other settings like,

• Picture profiles – Landscape, Portrait, Vivid etc…
• Automatic Shadow & Highlight recovery or enhancement.
• In camera effects like, Black & White photography.

Because the RAW data has been processed and rendered as a JPEG file it can no longer be processed and all settings are baked in. JPEG files represent the final image and that is why you have to get things right in camera before taking the picture.

The benefit of shooting JPEG is that camera manufacturers spend a lot of time evolving and calibrating camera settings, image sensors and image processors to produce great images straight out of the camera (OOC).

RAW files ignore most of the parameters set by your camera and you the photographer have to decide how you want your final image to look. Once you have finished applying edits and corrections to your RAW files, you have to process them and normally output them as a JPEG, DNG, or TIFF file. And just like the JPEG file that has been processed by your camera, the JPEG file processed by your image editing software will contain less data than a RAW file and also represents the final image in terms of processing.

Comparison between a camera processed JPEG and image editing software

You cannot see the RAW data from your camera until it has been processed, what you can do though, is take a RAW file and turn off all edits and corrections to see what it looks like. This is an interesting exercise in comparing an uncorrected RAW file with both a camera JPEG and a RAW file processed by an image editor, take a look at the three following images.

Here are my exposure settings, and for this exercise I shot both RAW and JPEG. I also took a spot reading from the brightest part of the sky then dialled in +2 exposure compensation to ensure that I retained detail in th sky and to set the sky as my brightest highlight.

The first one is the RAW file with no corrections or edits.

Now look at the OOC JPEG, this is the same RAW data processed in camera, I used a Lumix G9.

I was shooting into the light, as you can see my G9 has done a good job in processing the image, setting and applying the following,

• White Balance.
• Brightness.
• Contrast.
• Sharpening.
• Highlight / Shadow recovery.
• Noise reduction.

And here is the RAW file processed with DxO Photolab. If you shoot RAW then DxO PhotoLab is the best RAW file convertor out there.

Which processed image you prefer is a matter of preference, I could have opened the shadows more in the processed RAW file.

The real point of the exercise is to show that if you get your exposure right and exploit your cameras functionality, it is not always necessary to shoot RAW.

You should learn to exploit your cameras technology and functionality and also know when it is preferable to shoot RAW over JPEG. These days, I shoot RAW when I need to work with high ISO as vendors like DxO provide photographers with great noise reduction technology. Or, when I need to have more control over processing my images.

What is One Push AE

One Push AE (Auto Exposure) uses an assigned function button to automatically set a suitable exposure. It is primarily used in manual mode but can also be applied when using Programme shift .

How it works

When shooting in manual mode and metering a scene, if you press the assigned function button for one push AE, your camera will quickly adjust the combination of aperture and shutter speed to provide a suitable exposure for the scene being measured.

I find this function to be extremely useful when shooting in manual mode, I can quickly set a combination of aperture and shutter speed and then manually adjust the suggested exposure to fit my needs.

As an example, suppose I am shooting a bright street scene then I walk into a church to photograph the interior. The contrast between the two scenes would be enormous. I could dial in the correct combination of aperture and shutter speed manually to get exposure I want, but that would take several turns of the dials to do so. Using one push AE, I instantly have a suggested exposure set automatically by the camera and can then tweak the exposure to my liking manually, Perfect!

Why you should use it

In principle, you are combining auto exposure and manual exposure together allowing you to quickly meter a scene and then adjust the exposure manually to your liking. It is a fast and convenient way to combine auto exposure with manual control.

If you have not set this up on your camera then maybe you should give it a go. If you do let me know how you get on.

There are many photography articles that explain the different shooting modes of your camera. However, many of them do not explain the relationship between shooting modes, exposure, and metering.

If you want to understand how your cameras exposure modes work, then you must learn about exposure values or EV’s as there known. Once you understand this, then choosing and using your cameras different shooting modes easy.

Most photographers will have come across the exposure triangle.

However, the exposure triangle, misses the most important concept in photography, Exposure values (EV)!

Why is that important? Because for every given exposure value, there is a predetermined combination of aperture and shutter speed that can be used to ensure that whatever you are photographing is correctly exposed.

Exposure values are a set range of brightness values ranging from -6 (starlight night) to 16 (sunlight day). Exposure values can be higher, but in terms of photography these are the most quoted values.

So how do these values apply to photography? Simple, when you use your cameras internal light-meter, it measures the brightness of a scene or subject and sets an exposure value, this exposure value is translated into a shutter speed and F-Stop.

For example, at ISO 200 and with a metered scene brightness equivalent to EV 12, you can use the following combination of aperture and shutter speeds.

How does that relate to your cameras shooting modes? Your camera shooting modes range from fully automatic through to full manual control.

Camera modes simply provide a way for you to take some control or full control over your exposure settings.

And because there is a correlation between EV (scene brightness) and the use of ISO, Aperture and Shutter speed, making a change to one or more of these settings in a semi-automatic modes means that the camera will adjust the other parameters to ensure the exposure is identical.

Staying with our example, this means that at an ISO of 200 at a brightness value of EV12, our exposure would be F/8 @ 1/125s. So, in full auto mode, the camera will set an aperture of F/8 @ 1/125s.

In aperture priority mode – If you set the Aperture to F/8, the camera will set the shutter speed to 1/125s.

In shutter priority mode – If you set the shutter speed to 1,125s, the camera will set the aperture to F/8.

In programme mode – The camera will set the aperture to F/8 and the shutter speed to 1/125s.

This shows that each of these modes do parallel things by making one of the variables constant, and then changing the other one to give a correct exposure. Which means that, if you understand how they work, it will not not matter which semi-automatic mode you choose.

The only reason to choose either aperture priority (AP) or shutter priority (SP) mode is when you need to be absolutely sure that either your aperture remains constant (AP mode) or your shutter speed remains constant (SP mode).

Or you want to be more creative with your use of aperture or shutter speeds. In either of these modes you can vary one of the constants and arrive at a shutter or aperture speed of your choosing. In other words

Varying your aperture in AP mode changes your shutter speed. So, you can vary your aperture to arrive at a desired shutter speed.

Varying your shutter speed in SP mode changes your aperture. So, you can alter your shutter speed to arrive at a desired aperture.

I might almost argue that the only three modes you need on a camera these days are:

Intelligent Auto mode – camera looks after all settings.

Programme mode – with programme shift for fluctuating combinations of aperture and shutter speed.

Manual mode – to have full control over aperture and shutter speed combinations, and for varying exposure without using exposure compensation dials or buttons.

Whatever camera mode you use, your goal is to use your camera’s setting to give you the optimum exposure for the scene being photographed, and to use your aperture and shutter speed combinations creatively.

Handheld meters are very precise and can provide more information about the light in our scene and they can aid us in obtaining the optimum exposure for our scene.

Incident light meter readings

It is said that the most accurate form of metering is to use an incident light meter. Incident light meters measure the intensity of light falling on a subject and ignore the reflective properties of a subject.

Why is this important? Because no matter how light or dark the subject is, it does not effect the exposure reading.

If the same intensity of light is falling both on a lighter and darker subject then they both need the same exposure. Its that simple!

Reflected light meter readings

When we take reflected light readings, our exposure is effected by the intensity of the light being reflected back from our subject.

Our scene or subject is made up of different brightness values, dark tones reflect less light and brighter tones reflect more light.

A reflected light meter measures the light reflecting off your subject, taking into account the colour and brightness of the various elements in your scene (how dark or light your subject is) and this affects your reading.

Most cameras come with three types of inbuilt light metering. Matrix (sometimes called segment, multiple), center-weighted and spot metering.

Reflected light metering always requires that you evaluate the scene and when necessary apply some form of exposure compensation.

Incident light metring versus reflected light readings

Incident light metering is fast and accurate and provides you with the optimum exposure for your subject.

Recommended meters

Handheld light meters can be simple or more sophisticated and you need to think about what light meter will best meet your needs.

Many models also allow you to meter for flash and ambient light and if you use some form of flash you may want to ensure that you choose a meter that can read both ambient and flash lighting.

And some models also allow you to take spot meter readings.

Sekonic L-858D-U Speedmaster Light Meter

This light meter is aimed at both photographers and cinematographers. It is a very sophisticated meter providing

• Incident light readings
• Reflected spot metering
• Multiple metering
• Flash metering
• Balancing of ambient light and flash readings

And has a touch screen. It is for the more advanced shooter and it is what I use. It may be too sophisticated for some users but will cover all lighting situations. It also has wireless trigger control.

Some people may find it a little bulky but I live with that as it is such a good meter.

Sekonic L308X

This is an accurate a pocket-sized meter, the Flashmate L-308X light meter from Sekonic is compact, poketable and can meter both ambient and flash lighting as well as working in video with dedicated Cine and HD Cine modes. It has a sliding lumisphere so that you can measure ambient light as well as reflected light.

This meter is ideal for those who want to keep their metering simple and still get accurate exposures. Whilst it offers reflected light metering it is a meter that will mostly be used in incident mode.

Gossen Digisix 2

If you want to keep things really simple you can go for the Gossen Digisix 2. It takes incident and reflected light readings that can read off from an analogue display. It can also do contrast measurements.

The three light meters here provide something for every level of user. LIke cameras as your photogpahy skills evolve you may find that your camera needs evolve too. Before purchasing a light meter, think about how your photography needs might expand. You don’t want to have to replace yur meter because it no longer meets your needs.

Whilst most people use their camera’s inbuilt meter there is still a strong case for having a handheld light meter.

Handheld light meters are arguably more precise than our camera’s exposure meter and the more sophisticated meters provide us with more information from which to base our exposure.

There are two handheld light meters that I recommend looking at that have spot metering capabilities built into them. They are

• The Gossen starlite 2
• The Sekonic L858D

Both of these meters are very sophisticated and allow us to take both incident and reflected light readings, as well as measuring flash and providing the all-important spot metering capabilities.

When using a spot meter we are interested in

• Midtones
• Highlights
• Shadows
• Scene contrast
• The dynamic range of our camera’s sensor
• Settings the optimum exposure for our scene or subject

When taking spot meter reading we will do one or more of the following

• Base our exposure on a midtone reading and set our exposure accordingly (camera or handheld light meter).
• Take a highlight reading and make a +1, +2 or a + 3 stop adjustment to our exposure (camera or handheld light meter).
• Take a shadow reading and make a -1, -2 or a -3 stop exposure adjustment (camera or handheld light meter).
• Take a reading from our most important highlight and shadow area and average out the two exposures ( best done with a handheld light meter).
• Take multiple spot readings and average them out (best done with a handheld light meter)

Remember, all subjects have different reflective qualities

Reflected light metering measures the light reflecting from your subject and depending on how dark or light your subject, provides you with reading.

Because of these different reflective qualities and to get the optimum exposure for our subject or scene, we need to evaluate the scene and adjust our exposure accordingly.

When shooting with digital you need to be very accurate with your light readings. Unlike film, which has a wider latitude when it comes to your exposure, digital (especially JPEGs) requires you to be spot on with your readings.

Some examples

In time you will learn to judge how light or dark a subject is and set your exposure accordingly.

The next example uses a number of spot readings averaged out to give the correct exposure. The readings were taken with a Sekonic L758 light meter in spot meter mode and then average them out.

This was a high contrast scene and difficult to expose for. Handheld light meters are invaluable for scenes like this.

In our final example, I have metered from my most important highlight and shadow areas. The difference between the highlight and shadow areas is 7 stops, my camera’s sensor can handle 12 stops.

This is one of my favourite ways to meter as I know that the contrast range of my scene falls within the dynamic range of my camera’s sensor and that I have pinned my highlights and shadows to the correct zones, optimising my exposure. All of the other tones between my highlights and shadows fall into the correct zones.

Learning to meter like this can be very rewarding. You are taking control of exposure and making sure that your scene or subject is correctly exposed.

Remember: Light meters measure the intensity of light. There are two types of metering, incident and reflected.

Incident metering measures the intensity of light falling on the subject and
providing that we can measure the light falling on our subject, it is by far the most accurate way to ascertain the correct exposure for our scene or subject.

Reflected metering measures the intensity of light being reflected by our subject. Because of the different reflective properties of our subject or scene this intensity of light differs. Dark subjects reflect less light, bright subjects more.

It is because of these different reflective properties that we need to take control of our camera’s metering and adjust or apply exposure compensation as necessary.

In this blog post I want to talk about how to assess a scene and select the best exposure and in Part 3 of this blog I will talk about what to do when a scene falls outside of the dynamic range of your camera. But first a recap and some notes on histograms. and camera settings

Why you should not rely on your histogram

Your camera’s histogram only shows you the distribution of tones in your scene and whilst it is informative it is not an accurate way to control exposure.

Camera settings

Most cameras come with built-in light meters but when your camera is in anything but manual mode you don’t get to see the light meter, only the exposure compensation settings and perhaps a histogram

When you switch your camera to manual mode you are presented with a similar view but the exposure compensation value indicator turns into an expsoure meter with a number of stops shown.

In the shot above the camera is set to ISO 800 an aperture of F5 and a shutter speed of 1/40s. Spot metering has been enabled and the spot reading shows that the subject under the crosshairs is 2 stops brighter than the mean exposure.

Mean Exposure

What is mean exposure?

Without getting too technical, scenes are made up of a number of tones. Cameras use reflective light metering to measure the brightness of a scene or subject.

When using matrix or evaluative metering it measures the overall brightness of the scene or subject and then sets a mean exposure (average exposure for the scene) based on how dark or how light the scene or subject is.

This value is represented as zero (0) on your camera’s exposure meter (see above). Zero (0) equates to what is commonly known as zone 5, 18% grey or midtone.

18% grey represents the average reflectiveness of most day to day objects that we photograph and light meters are calibrated to produce an 18% grey tone.

The main point here is that if your subject is very dark or black your camera’s meter will set the exposure to brighten the subject. If your subject is very bright or white, your camera’s meter will set the exposure to darken the subject. Making them conform to 18% grey.

Knowing where your tones lie, taking spot meter readings from the most important tones and adjusting your exposure manually, so that your subject falls on the correct zone is the key to optimising exposure!

Spot Metering & Matrix Metering

Below is an every day scene, it’s made up of a number tones. Because the contrast range of the scene does exceed the dynamic range of my camera’s sensor, I was able to take the shot knowing that my shadows and highlights would render properly and not be too dark (underexposed) or too light (overexposed).

But how did I choose my aperture and shutter speed combination to ensure optimum exposure?

Let’s look at the scene from a tone perspective. Its made up of highlights, shadows and midtones. Notice that there are very few bright tones in this scene, the boathouse (highlight tone 8) is a relatively small percentage of the the overall scene but important in my shot.

If I had left my camera on matrix metering mode and used the exposure suggested by my camera, this would have happened.

The scene is a little washed out as the matrix metering has tried to average out the exposure giving more emphasis to the darker tones.

Because I knew this would happen, I used a handheld light-meter and took a spot reading from the boathouse as I did not want the boathouse to be overexposed.

Tones relate to stops, each zone is equivalent to 1 stop on your camera.

My spot-meter gave a mean exposure reading of F8 @ 1/1000s (zone 5). Remember whether your subject is dark or light, A reflected light-meter always sets a mean exposure. Knowing this, I set my expsoure to F8 @ 1/250s. giving my boathouse 2 stops more exposure, pinning it to zone 7.

When you put your camera in manual mode and combine it with spot-metering, you can assess the dynamic range of your scene, measure the important areas and set your exposure accordingly.

Here is the final image

The boathouse has been placed on zone 7 to ensure that there is detail in the boathouse and that it is not too bright and all of the other tones in the scene have been rendered appropriately. Giving me the optimum exposure for my scene.

Notice that working this way I have managed to retain the subtle detail of the clouds in the sky too.

More on Camera Metering Modes

Another benefit of working this was is that there is little, if any correction to be made when post processing as the exposure is spot on!

The better cameras come with three types of metering, Evaluative (also known as matrix or segment metering), Centrer weighted and Spot metering.

Matrix and centre weighted metering provide a general expsoure that may or may not be correct for the scene. But, the only way to truly evaluate your scene and set exposure accurately is to turn to spot metering.

In my next blog post I will focus on how I use the spot meter in my camera and the benefits of using a hand-held light meter. I will also talk about what to do when the scene falls outside of the dynamic range of your camera’s sensor.

What do all types of subjects have in common? They all reflect light! It does not matter whether you are shooting landscapes, portraits, still-life or any other subject.

Your subject will be made up of a number of reflective tones and your camera’s meter will measure these tones and set the exposure accordingly.

These tones can be thought of as shades of black and white and are called zones.

Each zone represents 1 stop.

• Zone 0 can be thought of as pure black
• Zone 5 is commonly referred to as a midtone.
• Zone 10 is pure white

(I have used this shot of my back garden as it has has a good tonal range for the purpose of this blog).

Most images are a mixture of tones.

When shooting in colour, it is hard to visualise these tones.

And when trying to optimise your exposure you need to consider the contrast range of your subject and the dynamic range of your camera’s sensor.

That means when you are assessing your scene, you need to know

• What are my important highlights?
•  Where are my midtones?
•  Where are my important shadows?
•  What is the overall contrast range of my scene?

Look at the image below

It’s made up of highlights, shadows and midtones.

The contrast range of these scene is within the dynamic range of my camera’s sensor. This means that I will have both detail in my highlight and in my shadow areas.

Anything outside of this contrast range will either be dark or shadow areas with no detail (black) or burnt out highlights or white with no detail. In other words, they will be Under exposed or Over exposed!

My Panasonic GX8 allows me to switch my live view to black and white and I use it to help me assess the contrast range in a scene. You might want to check your camera settings to see if you can do the same. I find that this helps me with composition also.

Let’s stick with the concept of zones for a moment.
Underexposure

When you make adjustments to your exposure you are moving the zones to the left or the right.

Look what has happened here a two stop underexposure (-2) has pushed all of the tones to the left. Zone 2 has now become Zone 0, which means that there will be no detail in the chair. And look at the sky, it was probably a Zone 9 but is now falls in Zone 7. We have more detail in the sky but have lost detail in the black chair.

Looking at the two histograms above of the same scene you can see that underxposing by two stops has moved the histogram to the right and we no longer have many midtones. The picture on the right has a more balanced exposure, the histogram is more even and the image brighter. Although we may be clipping some highlights.

Overexposure

The opposite happens when we increase our exposure.

The zones get pushed to the left and everyting gets lighter. Our chairs have turned grey when they are really black and the sky is now burnt out with no detail.

Optimising Exposure

An important concept is the notion of midtones. Every type of metering trys to turn your subject into a midtone (zone 5). Without getting into all of the techincal detail basically, most objects in a scene reflect light back at around 18%, half way between black (zone 0) and white (zone 10).

Meters measure how light or dark a subject is and then compensate or bias an exposure towards zone 5. pushing our zones to the left or to the right, zeroing out our exposure!

Practically, if a scene or subject reflects less light or is very dark, the meter will try to brighten the subject. If the scene or subject is very bright or light, the meter will try to darken the subject.

This is how sometimes our meters are fooled into providing an exposure that is perhaps not right for the subject. There is one exception to this and that is when we use an incident light-meter. Incident light-meters measure the light falling on a subject and not the reflective qualities of the subject. These meters are usually hand-held.

The question is; when using your camera’s meter, how can you visualise this, how do you optimise your exposure for the scene you are shooting and do you use evaluative (matrix), centre weighted or spot metering?

Matrix or evaluative metering, sometimes also called multi-zone metering divides the scene into a number of zones and tries to come up with an optimum expsoure. Providing that the proportion of highlight, shadow and midtones are roughly the same and the lighting fairly even and not to contrasty, this type of metering will do a good job.

This is the type of metering most people rely on. In this shot though, the top third of the scene is where the main highlights are and the rest of the scene has midtones or darker tones, this has caused the evaluative metering to bias the exposure and brighten the image.

As you can see, the sky has little detail and the histogram shows the bright areas of the sky pushed to the right side of the histogram.

Look at the same shot again using manual exposure settings and spot metering.

This exposure is more balanced. I have used two spot meter readings and averaged them out to pin my highlight and shadow details to the zones I want them to fall in.

Because I was thinking in terms of tones and metering my scene to  see where the important highlights and shadows fell, I was able to have full control over setting the optimum exposure.

Also, I could tell that my highlights and shadows fell within the dynamic range of my camera. Which means that all the tones between the highest highlight and deepest shadow will also be correctly exposed.

I have pinned my exposure and know with confidence that my exposure is optimised for the image. Your camera’s built in spot meter can do some of this but the best way to assess the scene in front of you and the most accurate way to set exposure is still with a hand-held lightmeter.

Of course, if the contrast range of the subject is outside of the dynamic range of your camera, then you will always lose some highlight or shadow detail or maybe both.

In summary

• Learn to assess your subject matter in terms of tones and tonal range
• Identify important highlight and shadow areas
• Measure the number of stops between the two and set your exposure accordingly
•  Make more use of your camera’s spot metering capbability
•  And finally, if you are serious about your photogrpahy consider geting a hand-held light meter.

I personally use a Sekonic handheld spot meter as it allows me to take multiple readings and average them out.

There is more to write on this subject but that is for another occasion. If you have any questions or need help leave a comment and I will reply.