Test Flashcards
What is the unit of measurement for light intensity?
Lux or Foot candles
How does a telephoto lens affect depth of field?
Decreases depth of field
What F-stop gives the greatest depth of field?
Higher number
Which lens has the least depth of field?
A telephoto lens with a wide aperture
What does ISO indicate
ISO measures the sensor’s sensitivity to light
(International Organization for Standardization)
What is a progressive scan of a digital scanner (PSF)
Scanning all lines of the frame sequentially and displayed in one frame, as opposed to interlace, where every other line is displayed at once, prevents combing
What is light
Light behaves as both a wave (travels, refracts) and a particle (photons interact with sensors).
Explain exposure latitude
The range of exposure where a film or sensor can capture detail without clipping highlights or crushing shadows
Explain and define quantum efficiency
The ratio of electrons generated to photons absorbed in a pixel; efficiency of a sensor at converting light to an image
What are microlenses on image sensors and what problems do they solve?
Microlenses focus light onto pixels, increasing efficiency and reducing light loss
Draw a diagram of a Bayer sensor pattern and explain.
Blue, red, two green filters make up each pixel to reduce aliasing. Double green for luminance human sensitivity. The information is combined to produce full color pixels (demosaiced), less complex than all colors in one photosite
Explain the compression scheme for subsampling for all cameras.
4:4:4 (no chroma subsampling), 4:2:2 (half horizontal chroma), 4:2:0 (quarter chroma sampling, used in consumer devices).
What is a pixel?
The smallest unit of a digital image, representing light intensity and color.
What does CODEC stand for?
Compressor-Decompressor or Coder and Decoder
What are IR cut filters?
Filters that block infrared light, preventing unwanted color shifts.
What is Long-GOP compression
Uses reference frames (I-frames, P-frames, B-frames) to reduce file size but requires more processing.
I-frame (Intra coded)
Complete JPG image
P-Frame
Predicted frame changing only moving parts of image
What is Intraframe compression?
Each frame is compressed individually (e.g., ProRes, DNxHD), making editing easier.
What is the cause of a rolling shutter?
Sequential scanning of the sensor, causing distortions in fast-moving objects.
Real advantages of higher bit depth?
More color accuracy, smoother gradients, and better post-processing flexibility.
Do humans have more accuracy and sensitivity with color or exposure?
Exposure (we are less sensitive to color precision than brightness changes).
How is color created through absorption?
Objects absorb some wavelengths and reflect others, which determines their color.
If you add all subtractive primaries, what is the color?
Black
If you add all additive primaries, what is the color?
White
Wavelength range in nm humans can see?
380mm-760mn
What is hue?
The specific wavelength of color.
What is saturation?
The intensity of a color (high saturation = vivid color, low saturation = muted color).
In human vision, what do the cones see?
Color (Red, Green, Blue cones).
What are the three basic properties of any lens?
Collects, refracts, focuses light
What are the benefits of lens coating besides reducing glare?
Reduces reflection, Increases light transmission, maintains sharpness
What is optical breathing?
A change in the image’s framing when adjusting focus, often seen in zoom and telephoto lenses.
Spherical aberration, one solution to fix it?
Light doesn’t focus to the same point because of the angle of incidence with a round shape of the lens. Use a field stop to block, aspheric glass, or low dispersion glass
Results of lens diffraction (what do we see)?
Loss of sharpness, soft image.
Explain the Scheimpflug principle?
Explains the focus range when the lens plane and image plane are not parallel, results in a subject focus plane that is diagonal
Besides reducing glare, what are two other effects of using a POLARIZER?
Increases color saturation, darkens skies, acts as an ND filter.
List three ways you can reduce depth of field?
Open aperture, increase focal length, move closer to subject. + larger sensor
Explain how you follow focus with marks?
Pre-mark focus points and pull focus accordingly.
What is the pluge, and how do you use it to calibrate a monitor?
3 grayscale bars used to adjust monitor contrast and black levels.
What is the purpose of setting the blue gun?
Turns off red and green ray guns, allows you to properly adjust saturation and hue
What aspect of a lens does the MTF lens chart test?
Sharpness and resolution of a lens.
Do you need to twist a PL lens?
No
Which leg on the C-stand do you put the sandbag on?
The tallest leg (or the opposite of the load side for stability).
Draw the correct additive primary color opposite the correct subtractive primary color.
Red ↔ Cyan, Green ↔ Magenta, Blue ↔ Yellow.
F stop = ?
Focal length/ aperture diameter
What aspect of a lens does the MTF lens chart test ?
Objective sharpness, resolving power, lines of resolution
