Tone in Photography – Shades of Grey and Exposure in Auto Mode

Your camera may be able to do all sorts of clever stuff but at the end of the day it isn’t really that clever.

It’s ability to make an image all comes down to the programmes within the camera and sometimes we need to take control and show the camera who really is the boss.

black bird in white background


Sometimes the camera can get confused as it is programmed to assume that every image has an average tone of about 18% grey which is known as the tone in photography.


This is why, sometimes, you struggle to get a photograph to look right even when it looks great to your eyes.

Key Points

  • A camera measures how much light is falling on your scene
  • The ‘tone’ is the difference between the lightest and darkest areas on a photograph
  • The camera programme turns every image to about 18% average grey tone
  • Not every image is 18% grey and this confuses the camera
  • A black cat in a coal cellar is made up of dark tones and the camera will overexpose trying to turn it lighter and closer to 18% grey
  • A white cat in the snow is made up of light tones and the camera will underexpose trying to turn it darker and closer to 18% grey

What is ‘Tone” in Photography

Tone or tonal range has a range of definitions in photography but the use here is to describe the differences between the very darkest part of a photograph and the lightest part of a photograph.

Dark tones are the shadowed areas on a photograph

Light tones are the bright or highlighted areas on a photograph

Our eyes automatically ‘see’ the range of tones in a scene and can distinguish detail in the very bright and very dark areas. However, the camera doesn’t do this automatically and misses some of the detail at the very edges of the tonal range. The camera struggles to define the tone as it assumes that the average tone of the whole image is 18%.

The overall tone in photograph is the average of all the tones. By turning the image to black and white and then blurring it out, the image you end up with is the overall tone and on auto mode this will be about 18% grey.

 A correctly exposed photograph is made up of a range of greys and blacks. Reducing the detail shows the overall tone of the image when all the different tones of the pixels are added up and averaged out. A camera will attempt to correct an exposure in auto mode to make the average grey to be about 18%
A correctly exposed photograph is made up of a range of greys and blacks. Reducing the detail shows the overall tone of the image when all the different tones of the pixels are added up and averaged out. A camera will attempt to correct an exposure in auto mode to make the average grey to be about 18%

Correct Exposure in Photography – tone

When you take a photograph in auto mode your camera will measure the amount of light falling on your subject.
It will juggle the exposure to make sure that the right amount of light passes through the lens and reaches the sensor.

The camera programme will ensure that the photograph you get is not too dark or too light (a bit of a Goldilocks moment as I write this!!)

This is fine for day to day snaps, but the camera will get confused once you try to get a little more adventurous.

The importance of tone in photography is more noticeable when using auto mode and there is little differentiation in tone between objects. It will struggle to capture a black cat in a cellar or a white kitten in the snow as the programme is constantly trying to give the 18% mid-grey average tone. It also won’t want to co-operate if you are trying to get the moody grey sky over a dark landscape or the white butterfly in a field of daisies.

The example below is an arctic tern in black and white against a grey overcast sky.
With the correct exposure there is a good range of black and white and the details are all really clear. When it is over exposed everything is too white and bright and the details are lost. At the opposite extreme when the image is underexposed it is all too dark and all the light details are lost.

On auto mode the camera would really struggle to work out where it should be setting the exposure and will attempt to go for a mid-grey average. This means that it may over or under expose the scene, trying to give the mid-grey tone it is programmed to achieve.

An example of correct exposure in a black and white photograph with over exposure and under exposure demonstrated.

Over Exposure – Too Much Light at Sensor – Image Too White or Bright
Under Exposure – Not Enough light at Sensor – Image too dark or Black

How can I get the correct tone in my photographs?

If you are comfortable shooting on auto mode and don’t want to change then unfortunately you are stuck with an average of about 18% grey on your photographs.

However, it is possible to show the camera who is in charge. By turning your camera off auto you can control how much light reaches the sensor and move away from the mid-grey tones.

You can control the shutter speed, size of the aperture and the ISO which allows you to capture the black cat in the cellar or the white kitten in the snow!

image to demonstrate how camera confuses white and black

Try it out!

If you don’t believe this happens try this little experiment!

Put your camera into auto mode and place two pieces of paper – one white and one black into a well lit area. Make sure there are no shadows, highlights or reflections on the paper.

Fill the whole of your photograph frame with the paper and take a photograph of each sheet. You may be surprised to find that they are both mid-grey!

You can take this further by placing black objects onto black paper or background and white objects onto white paper or background and see how your camera struggles to get the correct exposure or even out on adventures there are moments when this will catch you out!