Photography

Question 1

Explain depth of field

Answer 1

Depth of field in photography is the range of sharpness in an image, controlled by the camera’s aperture.

A wide aperture (small f-number) = shallow depth, isolating the subject,

A narrow aperture (large f-number) expands the depth, keeping more of the scene in focus for a balanced or detailed composition.

Question 2

Explain what the aperture does

Answer 2

Aperture in photography refers to the lens opening through which light enters the camera. Measured in f-stops (e.g., f/2.8), it affects depth of field and exposure. Wider apertures (lower f-numbers) create a shallow depth of field, while narrower apertures (higher f-numbers) increase depth of field, impacting image focus and light intake.

https://visualeducation.com/photography-course/aperture-depth-of-field/

Question 3

What is focal lenght

Answer 3

a. the distance to the subject
b. the distance either side of the subject which is optically clear
c. the length of the film
d. the distance light travels from the front of the optics to the film plane

Answer: the distance light travels from the front of the optics to the film plane

Question 4

Colours will disappear as light travels through seawater because of?

Answer 4

Absorption

Question 5

What will increase the depth of field?

Answer 5

Increase the f number

Smaller aperture (larger f-number) increases the depth of field in photography, keeping more of the scene in focus.

Question 6

What will increase the field of view of a lens?

Answer 6

A short focal length

Question 7

What is the main advantage of photography over CCTV?

Answer 7

It gives a very high resolution

Question 8

What best describes photogrammetry?

Answer 8

Stereo photography with computer assessment

Question 9

What is meant by bracketing the exposure during photography?

Answer 9

Taking 3 pictures varying the exposure to ensure the correct result

Question 10

If there is a need to increase the depth of field, what should be done?

Answer 10

Increase the F number

Question 11

When using close up prods for an NDT inspection which of the following should be done?

Answer 11

All of these

1. Bisect the angle between the components
2. Include a scale
3. Ensure the inspection is properly lit

Question 12

Which of the following best describes film speed

Answer 12

a. The speed with which the film can be advanced
b. the length of time a film is exposed
c. a numerical value relating to the sensitivity of the film
d. none of the above

Answer: a numerical value relating to the sensitivity of the film

Question 13

What is backscatter?

Answer 13

Light reflected back from suspended particles in the water

Question 14

What is the photosensitive part of a colour negative photographic emulsion?

Answer 14

Silver halide crystals

Question 15

A high ISO number on a digital camera signifies?

Answer 15

A fast reaction to light

Question 16

Macro photography is

Answer 16

Taking close-up photographs

Question 17

Focal length ratio factor is defined as?

Answer 17

Focal length divided by the aperture

Question 18

Which of the following is a definition of depth of field with regards to under water photography?

Answer 18

The distance in front of and behind the subject that is in acceptable focus

Question 19

What does the ISO number on a digital camera signify?

Answer 19

How quickly the camera electronics will react to the light.

Question 20

A badly positioned flash may cause

Answer 20

Illumination of suspended particles, possibly causing back scatter

Question 21

Why does the f-stop number get smaller when the aperture gets bigger.

Answer 21

The f-stop number is determined by the ratio of the focal length of the lens to the diameter of the aperture. The formula for calculating the f-stop is:

f-stop= focal length /
aperture diameter

As the aperture diameter increases, the f-stop number gets smaller. This is because the f-stop is essentially a fraction, and as the denominator (aperture diameter) increases, the whole fraction becomes smaller.

For example, if you have a lens with a focal length of 50mm and an aperture diameter of 25mm:

f-stop = 50 / 25
f-stop is 2, indicating a relatively large aperture.

https://visualeducation.com/photography-course/aperture-depth-of-field/

Think of the f-stop number as a fraction. It represents the ratio of the focal length of the lens to the diameter of the aperture opening. When the aperture gets bigger, the denominator of this fraction (the diameter of the aperture) gets larger.

Now, when you divide the same focal length by a larger number (the diameter of the aperture), the result is a smaller fraction. And since the f-stop number is the inverse of this fraction, it gets smaller as the aperture gets bigger.

So, when you see a smaller f-stop number, it means the aperture is larger, allowing more light to enter the camera. This is useful in low light conditions or when you want to achieve a shallower depth of field in your photographs.