Photography - Sharpness, Macro, Lighting, DoF Flashcards
Describe a macro lens.
Lens specifically designed for close-up work, with long barrel for close focusing anf optimized for high reproduction ratios.
What is the use for continuously-variable focal length macro lenses?
Suitable for virtually all macro subjects.
For what purposes can macro lenses with a focal length of 45-65 mm be used for?
3
- Product photography
- Small objects that can be approached closely without causing undesirable influence
- Scenes requiring natural background perspective
For what purposes can macro lenses with a focal length of 90-105 mm be used for?
3
- Insects
- Flowers
- Small objects from a comfortable distance
For what purposes can macro lenses with a focal length of 150-200 mm be used for?
2
Insects and other small animals where additional working distance is required.
Describe flood lights.
Provide a directional source of light.
What is the purpose of the barn doors on flood lights?
Help control light flow
What is the purpose of reflectors on flood lights?
Lighten the shadows created.
Compare spotlights to floodlights.
Spotlights provide a more directioonal light source.
What is the purpose of the rear control knob on spotlights?
Helps focus light beam
What can be done to a spotlight if further directional light is required?
Can be outfitted with a snoot
What is tenting in photography?
Lighting through a translucent medium to produce an even, diffused field of light devoid of reflected details (for shiny objects).
What can be done to eliminate the rainbow effect created when photographing reflective surfaces like CDs and DVDs?
Tented lighting in combination with a large aperture and limited depth of field.
What is transillumination?
Illumination produced by lighting through a translucent medium.
What is oblique lighting useful for?
2
- Accentuating surface detail
- Photographing cylindrical objects
What is the standard resolution of an AFIS print?
1000 ppi
What is dark field illumination?
Transmission of light below the object to be photographed.
In what instances is dark field illumination beneficial?
Powderedd finger/footwear impression on transparent materials.
How can lens flare be avoided during dark field illumination?
Never direct light at camera lens
Describe background separation lighting.
Subject separated from background on clear glass.
Separate lighting used for background and subject.
In what instances is background separation lighting useful?
Photographing small objects and physical matches involving textured materials.
Define depth of field.
Distance between nearest and farthest objectd which can be brought into acceptable focus.
What is the relationship between f-number and DoF?
Greater the f-number, greater the depth of field.
Describe the conditions under which greatest DoF is acheived.
3
- High f-number
- Short focal length
- Distant subject
True or false: There is only one plane of actual focus.
True
Describe the typical extension of the DoF behind and in front of the plane of focus.
1/3 in front
2/3 behind
Describe the extension of the DoF behind and in front of the plane of focus in close-up photography.
1/2 infront
1/2 behind
List the three factors that affect depth of field.
- Camera to subject distance
- Lens opening or aperture
- Physucal size of digital sensor or film
How does camera to subject distance influence DoF?
Closer you are to the subject, less depth of field.
How does lens openining or aperture affect DoF?
Smaller the aperture, greater the depth of field.
How does the size of the sensor or film affect DoF?
Smaller sensor or film = larger DoF
What is the most practical method to increase DoF, and what does this usually necessitate?
Smaller aperture
Slow shutter speed and/or tripod
Define the inverse square law.
Light falls off in such a way that as the light source to subject distance doubles, the light falls off by a factor of 4.
