Part four – Project 1 – Exercise 4.1

Project 1: Exposure
This section is all about light.

Exercise 4.1 / Part 1

Brief:
Set your camera to any of the auto or semi-auto modes.  Photograph a dark tone, a mid-tone and a light tone, making sure the tone fills the viewfinder frame.

Practical:
I used a black pair of trousers for my dark tone, the inside of a cereal packet for my mid-tone and a sheet of white paper for the light tone.  I put each by the window to photograph so I had as much natural light as possible, this was to help with obtaining a reasonable shutter speed whilst using the camera hand-held.

Results:
Even though the 3 materials were clearly different in tone to the naked eye, the camera did not ‘see’ things the same way. Here are the results for you to see:

Black trousers (dark tone)
img_8362-awb-av-dark-tone1

Inside of a cereal packet (mid tone)
img_8363-awb-av-mid-tone2


Sheet of white paper (light tone)
img_8364-awb-av-light-tone3

You might have reasonably expected the histograms to reflect the tones the camera was capturing, instead the histograms have captured what appears to be a mid-toned exposure for each of the images even though clearly to the naked eye the tones are very different.

“This simple exercise exposes the obvious flaw in calibrating the camera’s light meter to the mid-tone.”  As the camera averages each exposure around the mid-tone it does not know if the scene is dark or light.  The camera measures reflected light, not incident light i.e. the light which falls on to an object.  This is why a light meter is used, as a light meter measures incident light.

As you will see as I work through the exercises in this part of the course the camera can make some decisions about exposure for you and on fully automatic mode it does a pretty good job, however there are other times when you will not want the camera to do this and in those circumstances you will need to take your images on the manual camera setting mode.

Exercise 4.1 / Part 2

Brief:
Set your camera to manual mode.  Photograph a dark tone, a mid-tone and a light tone, making sure the tone fills the viewfinder frame.

Practical:
As with part 1 of this exercise I used a black pair of trousers for my dark tone, the inside of a cereal packet for my mid-tone and a sheet of white paper for the light tone.  N
ow that the camera is set to manual, the camera’s light meter is visible.

Results:

Black trousers (dark tone)

img_8367-awb-m-dark-tone  dark

Inside of a cereal packet (mid tone)

img_8366-awb-m-mid-tone  mid

Sheet of white paper (light tone)

img_8369-awb-m-light-tone   light

As you can see, this time the histograms are in the expected place and correspond to the relevant tonal values.

The reason for this is “Switching to manual mode disconnects the aperture, shutter and ISO so they’re no longer linked.  Because they’re no longer reciprocal, you can make adjustments to any one of them without affecting the others.”

The correct exposure can be achieved in a number of different ways, using a different combination of aperture, shutter speed and ISO.  It is important to understand the interaction between these 3 settings so you can make the correct choices under different shooting circumstances.

e.g. F8 1/60 sec. ISO 100   =   F5.6 1/125 sec. ISO 100   =   F8 1/125 sec. ISO 200

The ability to use different combinations of the three setting to get the same exposure is called Reciprocity.

Reflection:
Since I got my camera I have predominately used the manual setting and at times I have been frustrated with my trial and error approach when trying to get the correct exposure.  I understand how to use my camera’s light meter and heavily rely on this, to know whether an image will be under exposed or over exposed.  However, this part of the course has given me a greater understanding of how each of the exposure triangle components work in isolation and together, and that there isn’t just one way of exposing for an image.  I will experiment more knowing this and try to understand what each scene needs from a lighting persepctive and select the exposure elements as appropriate.

This completes my submission for Exercise 4.1 which concludes Project 1.  Now on to Project 2, ‘Layered, complex and mysterious…’ and Exercise 4.2.

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One thought on “Part four – Project 1 – Exercise 4.1

  1. Pingback: Part four ‘The Language of light’ – Introduction | BA (Hons) Photography : A Different Perspective

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