PPA CPP (Photography) flashcards

36 cards. Read the term and the definition here. The deck at the top of this page is optional.

Exposure value formula

EV = log2(N²/t) at ISO 100, where N is the f-number and t is shutter time in seconds. Each full stop changes EV by 1.

Reciprocal rule

For handheld shooting, the minimum shutter speed is approximately 1 divided by the full-frame-equivalent focal length. A 50mm lens on full-frame suggests 1/50s or faster.

Hyperfocal distance

H = f²/(N·c) + f, where f is focal length, N is f-number, and c is circle of confusion. Focusing at H gives acceptable sharpness from H/2 to infinity.

Crop factor

The ratio of the 35mm frame diagonal (43.27mm) to the sensor diagonal. It scales focal length and f-number for equivalent field of view and depth of field, not exposure.

Guide number

GN = f-number × distance for a flash at ISO 100. Distance = GN / f-number, and GN scales by the square root of ISO/100.

Inverse square law

Illuminance from a point source falls as 1/d². Doubling the distance reduces light to one quarter, a two-stop loss.

Key-to-fill ratio

The ratio of key light to fill light. A 2:1 ratio is one stop, 4:1 is two stops, and 8:1 is three stops of contrast between lit and shadow sides.

Mired shift

Mired = 1,000,000 / kelvin. Mired differences are additive, so a filter's mired shift can be added to a source's mired value to predict the result.

Flash duration t0.1

The time for flash output to fall to 10% of peak. It better predicts motion-stopping ability than t0.5, the time to fall to 50%.

Rule of thirds

A composition guideline that places key elements near intersections of lines dividing the frame into thirds. It is a guideline, not a law.

Gestalt principles

Proximity, similarity, continuity, closure, and common fate describe how viewers group elements. They explain why some compositions read as unified.

Perspective distortion

The change in near-far size relationships caused by camera-to-subject distance, not focal length alone. Moving closer exaggerates the effect.

Simultaneous contrast

The perceived hue and value of a color shift depending on surrounding colors. A gray patch looks darker on white than on black.

Bit depth

The number of levels per channel. 8-bit gives 256 levels, 16-bit gives 65,536, and 14-bit RAW captures 16,384 levels before demosaicing.

Dynamic range

The ratio of a sensor's full-well capacity to its read noise. A sensor with 14 stops records about 16,384:1.

Rendering intent

A rule for mapping colors between profiles. Perceptual compresses the full gamut; relative colorimetric preserves in-gamut colors and clips out-of-gamut colors.

ETTR

Expose to the right: place the brightest important highlight just below clipping to maximize signal-to-noise, then normalize brightness in post.

Demosaicing

Interpolating missing color channels from a Bayer color filter array. It can produce false color and moiré, reduced by optical low-pass filters or in-camera processing.

Non-destructive editing

Editing that preserves original pixels, using adjustment layers, smart objects, and masks. Direct brush and clone edits are destructive unless on separate layers.

Sharpening stages

Capture sharpening corrects demosaic softness, creative sharpening adds local emphasis, and output sharpening compensates for printer or screen.

Frequency separation

A retouching technique that separates texture from color, allowing skin tone and blemish corrections to be made independently without destroying detail.

Lift, gamma, gain

Color grading controls for shadows (lift), midtones (gamma), and highlights (gain). ASC CDL uses slope, offset, power, and saturation.

PPI calculation

PPI = pixels / inches. A 3000 × 2400 pixel file at 300 ppi prints 10 × 8 inches; at 150 ppi it prints 20 × 16 inches.

Halftone resolution rule

Output resolution should be about twice the halftone screen frequency. A 150 lpi screen needs roughly 300 ppi.

Black point compensation

A conversion option that maps source black to destination black, preserving shadow detail when converting between ICC profiles.

Soft proofing

Simulating a print profile on screen to preview how colors and tones will appear on the target device, with gamut warning for out-of-gamut colors.

CODB

Cost of doing business: annual overhead plus desired salary plus profit, divided by billable days. Day rate = CODB / billable days.

Usage licensing

Fees scale with media, territory, duration, and exclusivity. A buyout transfers broad rights for a higher fee than a limited license.

Model release

A signed permission from an identifiable person for commercial use of their likeness. Editorial use generally does not require one.

3-2-1 backup rule

Keep at least three copies of data, on two different media, with one copy off-site. It protects against drive failure, theft, and disaster.

Histogram clipping

A spike at the right edge indicates blown highlights; a spike at the left indicates blocked shadows. Gaps at either end indicate unused tonal range.

Intentionality in critique

Distinguishing a mistake from a choice. A tilted horizon, blown highlight, or soft focus can be valid if it serves the concept.

Portfolio sequencing

Opening with a strong image, varying rhythm and scale, and closing with a resonant image. Group by theme, color, or narrative.

Strobe electrical safety

Never touch a flashtube or capacitors; discharge before servicing. Use GFCIs in wet environments and keep stands weighted and cabled safely.

Copyright duration

In most jurisdictions, copyright arises on creation and lasts for the author's life plus 70 years. Registration strengthens enforcement.

Editorial vs commercial use

Editorial use informs or comments and has broader latitude; commercial use advertises and generally requires releases for identifiable people and private property.