Chapter 5- Camera Filters and Lighting

Question 1

In-Camera Filtration: Filters are available in many different material ranging from polyester to optical glass. What are the two methods of holding these in a camera?

Answer 1

Polyester, polycarbonate and actetate are are placedin standard filter holders which can be attached to the front of camera lenses
Optical glass, dyed gelatin sheets help in circulat metal mounts and can screw onto the front rim of the lens

Question 2

In-Camera Filtration: Why is it important to apply settings of the camera (especially exposure related ones) when the filter is already on the lens?

Answer 2

It affects the amount of light passing through (more expensive ones allow more light through, but cheaper ones reflect up to 12%)

Question 3

In-Camera Filtration for Monochrome Film Photography: What is the basic rule with colour filters about what coloured light it will let through?

Answer 3

A filter will pass light matching its own colour and absorb (darken) other colours, in particular those furthest away within the visible spectrum

Question 4

In-Camera Filtration for Monochrome Film Photography:Film is more sensitive to blue than the human eye. What does this lead to it doing to a blue sky and white clouds being imaged? How is this corrected?

Answer 4

They’re both recorded much paler than what is visualised by the eye. This is corrected by a Yellow K2 filter whereby the light is absorbed by the filter, making the clouds look more pronounced against a much darker background. A Deep Green (x1) filter results in the same effect but also makes foliage much lighter

Question 5

In-Camera Filtration for Monochrome Film Photography: What other filters may have a similar effect as the Yellow K2 one?

Answer 5

A Deep Green (x1) filter results in the same effect but also makes foliage much lighter
Yellow K2 acts as a correcting filter but orange and red filters tend to act as a contrast filter when used in the same situation. They would make the sky even darker, the red one making it almost black

Question 6

In-Camera Lighting: What is the ‘white-light’ source?

Answer 6

The source of light mostly used for photographic purposes, producing a mixture of all colours and continuous spectrum

Question 7

In-Camera Lighting: What is the actual colour of the white-light source measured in?

Answer 7

Degrees Kelvin (K)- scale starting from absolute zero (-273 degrees C)- this is based on the colour that metal emits when being heated ranging from dull red to orange and then from yellow and white through to blue

Question 8

In-Camera Lighting: Which of the following have the highest colour temperature (K) and which have the lowest?

Daylight (are there any lamps which are similar?0
Tungsten
Flourescent

Answer 8

Daylight has highest ranging from 5,000-10,000
(Metal Halide lamps are very close to daylight at 5,600- expensive and limited portability)
(electronic flash at 6,000, low heat output but intense light so also close match to daylight- also continuous)
Flourescent is next 3,000-6,500 (efficient and long lifetime with diffuse light)
Tungsten 2,700-3,200

Question 9

In-Camera Lighting: Can cameras adjust anything in response to light?

Answer 9

White balance. This can be affected by an accessory called the ExpoDisc which can take readings about the light used

Question 10

In-Camera Filtration for Colour Film Photography: Colour Correction- Conversion Filters: When would a conversion filter be used?

Answer 10

When the recommended light source cannot be used. It effectively changes the quality of light source to match the one the colour film has been balanced for

Question 11

In-Camera Filtration for Colour Film Photography: Colour Correction- Conversion Filters: If the conversion filter has an odd reference number (e.g 81A and 85B), what colour will it be? What about even numbers (e.g 80A and 80B)?

Answer 11

Odd= yellow/orange-lowering colour temperature
Even= blue- raise temperature

Question 12

In-Camera Filtration for Colour Film Photography: Colour Correction- Compensating Filters: What are the function of these compensating filters?

Answer 12

To control either red, green or blue regions whilst allowing the other two primary colours to pass through. These are only for minor adjustments to enable a slightly warmer or colder final result

Question 13

In-Camera Filtration for Colour Film Photography: Colour Correction-Compensating Filters: What do the numbers and letters mean in the name of CC filters? E.g CC20Y?

Answer 13

The filter density to the complementary colour of light and the final letter indicates filter colour

Question 14

In-Camera Filtration for Film and Digital Image Capture: What are the three important filters in this category?

Answer 14

Ultraviolet (UV) absorbing filter
Neutral density filters
Polarising filters

(others include Soft-focus, Close-up and Graduated)

Question 15

In-Camera Filtration for Film and Digital Image Capture: Which part of the film is sensitive to UV and what sort of effect does this have on the final image?

Answer 15

Upper emulsion layer and it leaves a blue appearance. In colour film, the filter removes this tint and in monochrome images, it removes any haze to show greater clarity

Question 16

In-Camera Filtration for Film and Digital Image Capture: What are neutral density filters?

Answer 16

Grey colourless filters that reduce the levels of light passing through the lens without having an effect on the colour rendition of the scene (or tonal range in monochrome images)

Question 17

In-Camera Filtration for Film and Digital Image Capture: When are neutral density filters used?

Answer 17

When you want to lengthen shutter speed (e.g to capture movement) or to use a wider aperture (to reduce depth of field)

Question 18

In-Camera Filtration for Film and Digital Image Capture: What do polarising filters do to light?

Answer 18

Light often goes many ways (in many directions) so this filter allows of prevents specific direction of light through the lens. This means that unwanted reflections disappear and restores contrast and colour saturation to all images. The filter is simply rotated to the desired angle

Question 19

In-Camera Filtration for Film and Digital Image Capture: What is a polarising filter made from?

Answer 19

A thin sheet of polarising material which is sandwiched between two circular pieces of glass.

Question 20

In-Camera Filtration for Film and Digital Image Capture: What two types of polarising filters are there and which can you use on autofocus cameras?

Answer 20

Circular and Linear but only circular can be used on autofocus since these cameras already polarise some light inside the camera

Question 21

In-Camera Filtration for Film and Digital Image Capture: What are soft-focus filters used for and how can this be achieved?

Answer 21

To create a softer look instead of sharp. Can be used to hide blemishes etc too. Vaseline, bubbles, ripples etc can be used to get this effect. ‘Lens baby’ focuses on particular parts to soften

Question 22

In-Camera Filtration for Film and Digital Image Capture: What are close up filters?

Answer 22

They are filters which shift the the camera’s plane of focus from infinity to the focal length of a close up lens- their magnification is measured in dioptres

Question 23

In-Camera Filtration for Film and Digital Image Capture: What is the shape of a close up filter and what strengths are there?

Answer 23

A convex meniscus. The strengths are +1, +2, +3 and +4 although it is possible to add two together but image quality will degrade

Remember that the images produced won’t be as good quality as with a Macro lens or photographic bellows and also when using this filter, it is advised to use a sturdy tripod

Question 24

In-Camera Filtration for Film and Digital Image Capture: What situations are graduation filters used in?

Answer 24

For landscape images to aid in achieving the perfectly exposed image in-camera. These filters aim to equalise the contrast between the land and sky sections

Question 25

In-Camera Filtration for Film and Digital Image Capture: Graduation filters can come in two forms; neutral density and colour graduating filters. What is the difference?

Answer 25

ND graduating filters are designed to lower contrast in bright skies. These are half clear and half coated and have a soft edged or hard edged transitional zone. The coated area should be positioned over the sky section, this will result in equal light across the whole image. Colour graduated filters are for creative effects-adding colour and mood to an image

Question 26

In-Computer Filtration for Digital Images: What are you doing to the image if you are changing Hue, Saturation or Lighting?

Answer 26

Hue- selecting a pure colour
Saturation- intensifying or diluting colour
Lightness- adding black or white to darken or lighten the image

Side note- These aspects are key to the Additive principle of colour reproduction (Red, Blue, Geen)

Question 27

In-Computer Filtration for Digital Images: What is Gaussian blur, Surface blur, Motion blur and Radial blur?

Answer 27

These blurring tools are:
Drawing attention to the foreground by blurring the background (Gaussian)
Reducing skin blemished on a portrait (Surface blur)
Adding the impression of movement (Motion and Radial blur)