Concert lens tool
Concert Lens Reach and Focal Length Calculator
Choose a sensor size, the distance from your shooting position to the performer, and the framing you want. The tool calculates the focal length that fills that frame, shows the same framing for full frame, APS-C, and Micro Four Thirds, and compares a lens you already own. Everything runs in your browser — no input or result is uploaded or stored.
How the focal length is calculated
The tool uses the framing triangle: the sensor height, the distance to the performer, and the height of the scene you want to fill. The full-frame focal length is 24 mm multiplied by the distance in metres, divided by the frame height in metres. That result is divided by your body's crop factor.
For example, at 20 m with a full-body frame of 1.9 m, full frame needs about 253 mm, APS-C needs about 168 mm, and Micro Four Thirds needs about 126 mm. All three hold the same vertical framing from the same position.
The comparison lens works in the other direction. A lens of a known focal length covers a stage height of 24 mm times the distance divided by the focal length, again adjusted for the crop factor. The tool then reports how much of the frame the requested subject fills.
What the framing presets mean
| Framing | Stage height held | What it includes |
|---|---|---|
| Full body | 1.9 m | 1.9 m of stage height, head to feet with a little headroom and floor. |
| Half body (waist up) | 1.05 m | 1.05 m of stage height, from the waist to above the head. |
| Head and shoulders | 0.6 m | 0.6 m of stage height, a close portrait crop. |
The presets are starting points for a standing performer, not fixed rules. A seated performer, a raised drum riser, or a very tall subject will change the height you want to hold.
Reading the result
The large number is the focal length for the sensor you selected. The full-frame equivalent is the same framing expressed in full-frame terms, so it is the number to compare across bodies. The table repeats the calculation for all three sensors.
The lens comparison is deliberately blunt. Below about 90% of the requested framing, the lens is wider than you asked for and the performer will fill only part of the frame. Above about 110%, the framing is tighter than requested and part of the performer will be cropped. Between those values the tool treats the lens as a match.
A result is arithmetic, not a guarantee. Sensors crop at slightly different ratios, lenses breathe as they focus, and the distance you estimate is rarely exact. Treat the focal length as a starting point and confirm the composition in the room.
What this tool does not do
- It does not model portrait orientation; the calculation uses the short side of the sensor and assumes a landscape still frame.
- It does not account for focus breathing, distortion, teleconverters, or in-camera crop modes.
- It does not verify stage access, venue rules, or whether a lens is permitted at a show.
- It does not upload, save, or transmit any field, file, or result.
- It does not recommend a specific lens to buy or claim that one focal length suits a whole performance.
Common questions
How should I measure the distance to the stage?
Measure from the spot where you will stand to the performer, not to the stage edge or the photo-pit barrier. If you cannot measure the room, estimate from a seating chart or from the venue's published dimensions and accept that the result is approximate.
Why does the same distance need a different focal length on each sensor?
A smaller sensor records a narrower field of view at the same focal length. The table divides the full-frame result by the nominal crop factor, so a 1.5× APS-C body needs a shorter lens than full frame to hold the same framing from the same position.
What does the lens comparison tell me?
Enter a focal length you own and the tool reports the stage height that lens covers on your sensor at that distance. It also shows how much of the frame the requested subject fills. A result within about 10% of the requested framing is treated as a match; outside that band the page suggests cropping, moving, or changing lenses.
Does this account for zoom lenses, focus breathing, or distortion?
It uses a single focal length for the comparison, so a zoom is evaluated at the number you enter. Focus breathing, distortion, and lens corrections are not modelled. The arithmetic describes geometric framing, not the exact edge-to-edge result of a specific lens.
What if the performer moves around the stage?
Re-run the calculation for the closest and farthest positions that matter. The required focal length changes directly with distance, so a performer at the front of the stage needs a shorter focal length than the same framing at the back.
Plan the rest of the kit
Focal length is one part of a concert setup. The lens guide covers mount-aware options, and the sensor comparison explains what changes when you move between full frame and crop bodies.