Introduction to Photography

A PRESENTATION BY SEAN O’MAHONEY

Learning Aims

By the end of this presentation, you should know what the following Photography terms are, and how to use them in for the pictures you take.

• Exposure (Exposure Triangle)
• ISO
• Aperture / Depth of Field (DOF)
• Shutter Speed
• Histograms
• White Balance
• Focal Length
• Perspective / Distortion
• Image Sensors (Crop Factor)

Exposure (Exposure Triangle)

• There are three core components when getting an ideal amount of exposure in an image.

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• Exposure being the amount of light thought-out the image, ideal exposure is not too dark nor too light overall.

ISO

• This refers to the sensitivity of the sensor, being too sensitive will be prone to grain (which you can see on the right), you will balance your ISO to the following two settings.

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• Shooting at night time or in dark places hand held, will require a higher ISO to let more light in.

Aperture

• This refers to the opening of the blades in the camera, which allow in light.

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• Measured in f-stops as you can see to your right, the lower the number, the more open the blades.

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• More open means more light is allowed in, as well as a greater depth of field.

Depth of Field

• Using the aperture as discussed in the previous slide, you can control the depth of field, this being what’s in focus, where a more closed aperture leaves a flat all in focus image.

Shutter Speed

• This refers to how long the sensor lets in light.

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• As seen to the right, the faster fraction of a second you shoot at, the more you can freeze fast moving objects.

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• Usually shooting slower than 1 over your focal length, shooting at 50mm, usually don’t shoot slower than 1/50.

Histograms�

• This is a graph that you can get up on your camera or in post processing.

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• It analyses all pixels within the image then maps them on a graph.

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• The more blacks you have, the higher it will be on the left.

White Balance

• White Balance is the tone of an image and getting it neutral.

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• To the right we can see a warm picture (maybe taken on a summers day), a cold picture (maybe taken during the winter), then a neutral picture, which is ideal and can be from either of the previous two with correction.

Focal Length

• A standard kit lens for a DSLR camera has a 18-55mm focal length, but what does that mean?

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• It is essentially what will be viewable in frame, what the sensor will capture.

Perspective / Distortion

• This is wide angle lenses magnifying and stretching parts of the image

Image Sensors (Crop Factor)

• A sensor will only capture a certain portion of a lenses view (demonstrated on the right).

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• A full frame sensor will take up a full rectangle.

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• Although a crop or smaller sensor type will take up less.

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• On Canon this is a crop of 1.6 (10mm lens would be a 16mm equivalent).