Tag Archives: angle

Types of reflection

Light, Science & Magic, 4th edition. By Fil Hunter, Steven Biver, Paul Fuqua.
Published by Focal Press, Taylor & Francis Group.

Light reflects differently depending on the surface that it is hitting.

There are three types of light reflection to consider in photography – direct reflection, diffuse reflection and glare. In some cases there may be a mixture of the three different types of reflection from the subject to be photographed.

Diffuse Reflection – evenly reflected light.
White paper is a good example for diffuse reflection as no matter which direction the light source is coming from the paper reflects the light evenly across the it’s surface. If three cameras where set up around the paper equal distances away from the paper, they will all record an image of the paper with the same brightness. This is because the surface is scattering the light in different directions allowing all three cameras to capture the reflected light from the paper. This type of reflection will have much softer highlights if it has any at all.

Direct reflection – is light bouncing off a surface whilst maintaining its original intensity. A mirror is a good example for producing direct reflection as it will reflect the light keeping it’s original intensity. The brightness of direct reflection also remains the same regardless of distance only the size of the area will change. With direct reflection the light will also bounce of the mirror at the same angle as it hit the mirror. Or in other words,

the angle of incidence equals the angle of reflection

As a result to view this reflection a camera must be positioned in line with the angle of reflection (in other words within the family of angels). However, from any other angel around the mirror the camera doesn’t see the reflection.

Glare – is polarized direct reflection this can be polarized light from source or by the material that it is reflecting off. A good example of a surface that creates polarized direct reflection is water.
Perfectly polarized direct reflected is exactly half as bright as unpolarized direct reflection. Like unpolarized direct reflection it bounces off a surface in the same way; so the reflection can be only seen from the one angle.

Exercise – Diagonals

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In this exercise I have looked at the use of diagonals in composition to create dramatic and interesting compositions and can also create a sense of movement.

This first picture creates a sense of tension and drama by observing this monument from below at an angle. The resulting diagonal image exaggerates the height and also suggests a feeling of vulnerability for the observer.

In this example, I have used the theory of diagonals to lead the viewers eye in to the picture. I thought that This foot bridge was a good choice of locations as it offered both depth and interesting shadow effects.

In this example, I have used the diagonals to draw attention to the subject, Holly, my dog.

In this final example, I have photographed a large scale model of Concorde displayed on a roundabout outside Brooklands Museum. By using the theory of diagonals I have created a sense of drama, as if I have caught an image of Concorde just as it is taking off right in front of me.

Exercise – Positioning a point

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In this exercise I have put in to practice my lesson on positioning a point of interest in the frame.

In this case I wanted something small surrounded by an unfussy even background. By using the three typical classes of position, I took three photos of the subject, one in the middle, one off centre and one close to the edge of the frame.

This image works as a snap shot style of photography; but I don’t find that it is particularly interesting from a compositional point of view as the eye would naturally go to the centre of the picture anyway.

This composition works much better as the subject appears to be looking into the empty space in the bottom right and therefore gives the empty area a sort of purpose.

This is my favourite, I chose to take this photo from a different angle as I think that viewing the subject from the same direction that she is facing gives both a sense of sharing her view and creating a feeling of voyeurism, anyway it works.

Exercise – Focal lengths – for cameras with variable focal lengths (with a zoom or interchangeable lenses)

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The object of this exercise is to appreciate the simplest effect that the changing of lenses from a short focal length to a long focal length can make with regards the amount of view taken in from these different focal lengths. I tried to find a subject of some interest with fore and background and settled on the ruined building that I framed to the right of the overall image to give a sense of place and context. I was lucky to have a roughly shaped triangular field of bluebells in the foreground for the long focal lengths which also added colour. From closely examining all the photos I notice that although the magnification changes from one photo to another the relationship of different objects doesn’t alter from one another, in this case by examining the tree in relation to the chimney in all the photos illustrates this point very clearly.

I set my camera upon a tripod and kept the tripod in the same position for all the photos, only slightly altering the composition by repositioning the subject in the view finder. I kept the camera setting to ISO-200 with the white balance set to auto and aperture priority set to f/8 for all the images taken and I have mentioned the different shutter speed as they automatically changed for each focal length under each picture.
I have used both primary and zoom lenses for this exercise: 24mm, 50mm, 105mm and a zoom 55-300mm DX (1.5 ratio) lens. When quoting focal lengths for images taken with the zoom lens I have quoted both the 1.5 (DX) focal length and the equivalent full frame (FX) focal length above each relevant photograph.

Prime 24mm wide angle

Due to the wide angle of this lens the attached lens hood created a slight vignetting but I decided not to crop it out as I want to fully illustrate the full width of angle created from this focal length. Shutter speed 1/640.

Prime 50mm (Standard focal length)
This is the standard focal length for 35mm SLR film camera and as my camera DSLR has a full size sensor this is also the equivalent standard focal length for my camera. This means that it is approximately the same angle of view as that of the human eye. Shutter speed 1/400.