Introduction
The Focus Puller Distance Chart Generator creates a calibrated table of focus distances with their corresponding near and far depth of field limits for any combination of lens focal length, aperture (T-stop or f-stop), and sensor size. Each row shows the set focus distance, near limit, far limit, and total DoF. An optional column shows hyperfocal distance for zone focusing. Print the chart and tape it to your mattebox for instant on-set reference without running mental math during takes.
What This Tool Calculates
The calculation uses the standard DoF equations from the ASC Manual. Circle of confusion = sensor width / 1500 for cinema work. Hyperfocal distance H = (f squared) / (N times c) + f. Near limit = (H times d) / (H + d - f). Far limit = (H times d) / (H - d + f), where d is focus distance, f is focal length in mm, N is f-stop, and c is circle of confusion. Worked example: 85mm at T2 on Super 35 (24.89mm). CoC = 0.0166mm. H = 217.7m. At 3m focus: near = 2.96m, far = 3.04m, total DoF = 8.1cm — tight enough to rack focus between eyes at conversational distance.
The Formula and How It Works
For a narrative two-hander dialogue scene, a first AC generated a chart for 100mm T2.8 on ALEXA Mini LF covering 1.5m to 5m in 25cm steps. At 2.5m the DoF was 5.3cm, requiring a physical mark for a critical rack between actors. For a documentary run-and-gun setup with 24mm T3.2 on Sony Venice, the chart showed a 12m hyperfocal — setting focus to 12m kept everything from 6m to infinity sharp without touching the focus ring. For a tabletop commercial, a 100mm T4 chart on Micro Four Thirds showed a 0.9cm DoF at 45cm, alerting the art department to keep the product label plane parallel to the sensor.
Real-World Examples
DoF Reference by Focal Length at 3m (Super 35)
At T2: 24mm gives 1.32m total DoF, 35mm gives 0.55m, 50mm gives 0.24m, 85mm gives 0.08m, 135mm gives 0.03m. At T2.8: 24mm gives 1.87m, 35mm gives 0.78m, 50mm gives 0.33m, 85mm gives 0.11m, 135mm gives 0.04m. At T5.6: 24mm gives 3.93m, 35mm gives 1.61m, 50mm gives 0.67m, 85mm gives 0.23m, 135mm gives 0.09m. These figures confirm that telephoto and fast aperture combinations demand the finest chart step increments.
Pro Tips and Common Mistakes
| Detail | Value |
|---|---|
| Generate charts in both metric and imperial when working with international crews. | |
| Print both and mark your preferred unit larger. | |
| For long lenses (135mm and above), use 5cm step increments from 1m to 4m — 25cm steps produce unusable gaps at those focal lengths. | |
| Tape the chart with closest distances at the bottom and farthest at the top, matching the way your follow focus wheel reads during a normal push forward. | |
| The most common mistake is generating a chart for the wrong sensor mode: a Full Frame camera in Super 35 crop mode requires a Super 35 chart, not a Full Frame chart.. |
Pro Tips and Common Mistakes
Pro Tips
- A well-generated distance chart eliminates on-set mental math for focus pulls and lets the entire camera department prepare marks before blocking begins.
- This tool generates the chart in seconds, allows metric or imperial output, and produces a clean table ready to print or display on a tablet..
Common Mistakes
Frequently Asked Questions
How do I use a focus distance chart on set?
Print the chart and tape it to your mattebox or camera cart. During blocking, confirm subject distances with a measuring tape. Find those distances on the chart and mark the corresponding focus positions on your follow focus wheel with tape or a grease pencil.
What is zone focusing?
Zone focusing means setting your focus to the hyperfocal distance so everything from half that distance to infinity appears acceptably sharp. Use it for run-and-gun documentary and handheld work where adjusting focus while tracking a subject is impractical.
Do breathing lenses affect the chart accuracy?
Yes. Photo lenses can shift focal length significantly at close focus distances, changing both the effective focal length and the DoF. Cinema lenses are designed to minimize breathing. For adapted photo glass, verify accuracy empirically at close focus distances.
Can I use this chart for autofocus cameras?
Yes. Even on autofocus cameras, the chart reveals whether the total DoF at your planned distance is wide enough for the AF system to hold. If DoF is 2cm and the subject is moving erratically, autofocus will struggle regardless of system speed.
Start Calculating
Use the calculator above to run your numbers before your next production.
