Calculates the range of distance in front of and behind the focus point that appears acceptably sharp. This is the most fundamental optical calculation for cinematographers choosing lenses and planning shots.

The circle of confusion (CoC) is calculated using the Zeiss formula (d/1500) — dividing the sensor diagonal by 1500. This is the standard used by professional cinematography tools such as pCam and ASC reference tables. For full frame sensors (43.27mm diagonal), this yields a CoC of approximately 0.029mm. Smaller sensors use proportionally smaller values, reflecting the greater magnification needed for the same output size. When a sensor mode or crop is selected, the CoC is recalculated from the active sensor area rather than the full sensor, since windowed modes effectively behave as a smaller sensor. Standard viewing conditions are assumed (image viewed at a distance approximately equal to its diagonal). If your camera's specific crop mode isn't listed in the sensor mode dropdown, select the closest matching generic sensor format from the camera dropdown for the most accurate results.

Determines how much of a scene a lens captures at a given distance, expressed as angular coverage and physical dimensions. Essential for planning shot composition, set design, and green screen coverage.

Diagonal angle of view uses the sensor diagonal (√(w² + h²)) in place of w or h. These formulas assume rectilinear (non-fisheye) lenses and do not account for lens breathing, which can slightly alter the effective focal length as you change focus distance.

The closest distance at which you can focus while keeping everything from half that distance to infinity acceptably sharp. A powerful technique for landscape cinematography, wide establishing shots, and deep-focus compositions in the style of Gregg Toland or Robert Richardson.

This is the same formula used in the DoF calculator's hyperfocal field. When you focus at the hyperfocal distance, objects from H/2 to infinity will be within the circle of confusion limit. In practice, "acceptably sharp" depends on your delivery format and viewing distance — a cinema screen demands tighter tolerances than a phone.

Compares how different sensor sizes affect the effective field of view and depth of field characteristics of a given lens. Critical when moving between camera systems or mixing formats on the same production.

The equivalent aperture affects depth of field only, not exposure. A 50mm f/1.4 on Super 35 gives the same field of view as roughly a 75mm on full frame, and the same depth of field as roughly f/2.1 on full frame — but the exposure remains f/1.4 in both cases. This distinction matters for lighting setups.

Compares your light meter reading (scene brightness) against your camera settings to show exactly how many stops over or under you are, with actionable compensation suggestions across aperture, ISO, shutter angle, ND, and lighting.

The 180° shutter rule: at any frame rate, a 180° shutter angle yields a shutter speed of 1/(2×fps), producing the motion blur characteristics most audiences perceive as natural. In cinema, shutter angle is almost never adjusted for exposure — ND filters are the primary tool for controlling light outdoors, which is why the tool defaults to locking shutter angle. The lock/unlock system lets you specify which parameters you're willing to change, and the tool only suggests compensations for unlocked parameters.

Determines the neutral density filter required to achieve a desired aperture while maintaining your chosen shutter angle and ISO. On-set, this is one of the most common calculations a 1st AC or DP performs when light conditions change.

ND filters are specified in three common systems: stops (each stop halves the light), optical density (ND 0.3 = 1 stop, ND 0.6 = 2 stops, etc.), and factor (ND2 = 1 stop, ND4 = 2 stops). This calculator converts between all three and finds the nearest standard filter. In practice, stacking ND filters is common — an ND 0.6 + ND 0.9 = ND 1.5 (5 stops).

Converts between timecode (HH:MM:SS:FF), total frame count, real-time duration, and the feet+frames system used in film editing and lab work.

This calculator uses non-drop-frame timecode. Drop-frame timecode (used in 29.97fps NTSC) skips frame numbers at specific intervals to keep timecode in sync with real time — it does not drop actual frames of video. The feet+frames system remains relevant for productions shooting on film and for lab work, where footage is physically measured.

Provides a visual comparison of cinema and broadcast aspect ratios. No calculation is involved — the tool renders proportionally accurate rectangles using the CSS padding-bottom technique to maintain correct ratios regardless of screen size.

Common cinema aspect ratios have evolved significantly since the Academy ratio (1.375:1) was standardized in 1932. The introduction of CinemaScope in 1953 led to the anamorphic widescreen ratios still in use today. Modern productions often frame for multiple deliverables — a 2.39:1 theatrical composition may need to work as a 16:9 home video and even a 9:16 vertical crop for social media, making ratio awareness essential during production.

Estimates recording data rates and storage requirements based on resolution, frame rate, bit depth, and codec compression. Helps plan media management, storage purchases, and data transfer time for DITs and post-production.

Compression ratios are approximate and vary by scene complexity. ProRes and DNx codecs use intraframe compression (each frame independently), while H.264/H.265 use interframe compression (referencing neighboring frames for higher efficiency). The values here represent typical averages — high-motion or high-detail footage will produce larger files than static scenes at the same settings.

Converts between stops difference and the traditional lighting ratio notation used in cinematography, allowing you to communicate contrast levels precisely with your gaffer and lighting team.

The distinction between contrast ratio and lighting ratio is a common source of confusion. A 2-stop difference means the key light is 4× brighter than the fill (4:1 contrast ratio), but the lit side of the face receives both key and fill (4+1=5), giving a 5:1 lighting ratio. Classic Hollywood portraiture typically sat around 2–3 stops difference. Modern dramatic cinematography often pushes to 4+ stops, while broadcast and comedy tend to stay under 1.5 stops for a flatter, more even look.

Calculates the mired shift needed to convert between color temperatures using gels or camera white balance. The mired system is used because equal mired shifts produce equal perceptual color changes regardless of starting temperature.

The mired (micro reciprocal degree) system was developed because the Kelvin scale is not perceptually uniform — a 1000K shift from 2000K to 3000K is far more dramatic than from 8000K to 9000K. In mireds, equal shifts produce equal visual changes. Standard conversion gels: Full CTO ≈ +131 mireds, Full CTB ≈ −131 mireds. Plus and minus green gels address the separate magenta–green axis not covered by the Kelvin scale.

Calculates total electrical load for a lighting setup, including amperage at different voltages and minimum generator size using the industry-standard 80% loading rule.

HMI fixtures draw significantly more from the wall than their lamp rating due to ballast inefficiency — a 1.2K HMI draws approximately 1800W. LED fixtures are generally more efficient. When working with household power (120V/15A or 20A), each circuit provides only 1800W or 2400W at 80% load. Generators are rated in kVA (kilovolt-amps), which equals kW for resistive loads but may differ for inductive loads like HMI ballasts.

Calculates the relationship between shooting frame rate and playback frame rate, including the resulting speed change, playback duration, and exposure compensation needed.

Overcranking (shooting faster than playback) creates slow motion but reduces the light reaching each frame because the shutter is open for less total time per second. At 120fps for 24fps playback, you lose approximately 2.3 stops of light. Undercranking (shooting slower) creates sped-up motion and gains exposure. At very high frame rates (200fps+), be aware of LED/HMI flicker — use DC-powered or high-frequency fixtures.

Calculates sunrise, sunset, solar noon, golden hour, and blue hour times using standard solar position algorithms based on latitude, longitude, date, and timezone.

Golden hour is the period shortly after sunrise and before sunset when the sun is low (0–6° above horizon), producing warm, directional light ideal for cinematography. Blue hour occurs when the sun is 4–6° below the horizon, creating even, cool-toned ambient light. These windows vary dramatically by latitude and season — they can last over an hour in high latitudes during summer, or as little as 20 minutes near the equator.

All lens and sensor calculations use measured sensor dimensions from each camera. The database includes over 70 cinema and digital video cameras with the following data for each:

Sensor dimensions reflect the maximum active area as specified by each manufacturer. Actual recorded area may vary by resolution mode, aspect ratio, and whether sensor windowing or line-skipping is used. Generic sensor format options (Full Frame, Super 35, etc.) use industry-standard reference dimensions.

The circle of confusion (CoC) determines what counts as "acceptably sharp" in depth of field calculations. It represents the largest blur circle that will still appear as a point to the viewer at a standard viewing distance.

These values assume a standard viewing distance of approximately the diagonal of the projected image. For cinema projection on large screens, tighter CoC values are sometimes used — some practitioners prefer d/1730 (the stricter original Zeiss value). The values listed here use d/1500, which is the standard used by professional tools like pCam and ASC reference tables. You can override the CoC value directly in the DoF and Hyperfocal calculators if you prefer a different standard. When a camera from the database is selected, its CoC is computed from its actual sensor dimensions rather than using a generic category value.