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) value is calculated from the camera's sensor diagonal relative to full frame (43.27mm diagonal). For full frame sensors, the standard CoC is 0.030mm. Smaller sensors use proportionally smaller CoC values, reflecting the greater magnification needed for the same output size.

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.

Calculates exposure value and converts between the cinema convention of shutter angle and the still photography convention of shutter speed. Useful for communicating between departments and converting light meter readings.

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. This convention dates to the rotary disc shutters in film cameras. Lower angles (e.g., 45°, 90°) produce crisper, more staccato motion — a technique used to great effect by Spielberg in the Omaha Beach sequence in Saving Private Ryan.

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 key:fill ratio and lighting ratio is a common source of confusion. A 2-stop difference gives a 4:1 key:fill ratio but a 5:1 lighting ratio — because the lighting ratio measures the total light on the key side (key + fill) against the fill side alone. Classic Hollywood portraiture typically used 2:1 to 4:1 lighting ratios, while modern dramatic lighting often pushes to 8:1 or beyond.

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.

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. The values listed here are the Zeiss formula standard, widely used in the motion picture industry. When a camera from the database is selected, its CoC is computed from its actual sensor dimensions rather than using a generic category value.