Lenses and Focus
Shift Lens Coverage Calculator
Calculate required image-circle coverage from sensor size and shift.
Enter the optical values
For Shift Lens Coverage, keep sensor format, units, focus state, and reference planes attached to the entries.
The lens or focus result will appear here with supporting checks.
Choose the sharpness criterion for Shift Lens Coverage
Calculate required image-circle coverage from sensor size and shift.
Shift Lens Coverage Calculator reports required image circle from Sensor width, Sensor height, Lens shift. Check the minimum image circle for a shifted frame.
Depth of field and diffraction outputs depend on an explicit acceptability or sampling threshold.
Inputs that define required image circle
Record Sensor width and Lens shift from one camera, lens, focus setting, and frame. Preserve the unit printed beside Sensor width and Lens shift; converting one without the other changes the geometry behind required image circle.
Identify whether Sensor width came from EXIF, the lens scale, a test frame, a sensor specification, or direct measurement before comparing another Shift Lens Coverage setup.
The calculation behind Shift Lens Coverage
Calculate required image-circle coverage from sensor size and shift.
For Shift Lens Coverage, the page keeps the intermediate geometry visible and rounds only the displayed required image circle. Run both a permissive and conservative criterion to see the practical range.
Worked check with the published values
For Shift Lens Coverage, calculate the defaults and save the displayed required image circle with its supporting quantities. Change only Sensor width in the Shift Lens Coverage example, predict the direction of required image circle, and calculate again.
Restore Sensor width and confirm the first result returns. That reset test distinguishes a real change in required image circle from a stale Sensor width value or an unnoticed unit conversion.
Where the required image circle model stops
Shift direction matters; this model applies the entered shift along sensor width.
Required image circle cannot judge the lens rendering, autofocus repeatability, decentering, field curvature, contrast, stabilization, or the success of the intended composition.
Measurement boundary for Shift Lens Coverage
Define the reference plane for Sensor width and what is included in Lens shift. For Shift Lens Coverage, a distance referenced to the sensor cannot silently replace one measured from the lens front, mount, principal plane, or subject surface.
For Shift Lens Coverage, list any crop, correction profile, teleconverter, extension, close-up element, breathing, or shift already represented by Lens shift. Apply each Shift Lens Coverage adjustment once—either inside the entered measurement or explicitly afterward, never in both places.
Reading the result in practice
Compare required image circle with a test frame, focus chart, measured field width, sensor specification, or known limiting case. If that check disagrees with required image circle, inspect the units and the reference plane used for Sensor width before changing the formula.
The Vignetting Cosine Fourth Calculator addresses a nearby lens question, but its output should be transferred only when the format and geometry remain the same.
Precision and available settings
Keep full precision while required image circle feeds another calculation, then round to the precision supported by the lens scale, rail, sensor specification, or field measurement.
Extra decimals in required image circle cannot repair uncertainty in Sensor width, Lens shift, pupil location, focus breathing, or the selected sharpness criterion.
Saving a reproducible lens record
Save Sensor width, Sensor height, Lens shift, required image circle, camera format, lens state, focus distance, and date. Mark nominal specifications separately from measured values.
For Shift Lens Coverage, when the lens, format, crop, focus, or camera position changes, preserve the earlier Shift Lens Coverage case and calculate a labeled replacement.
Designing a useful test for Shift Lens Coverage
For Shift Lens Coverage, choose a subject with measurable edges or planes and keep the camera position fixed unless distance is the quantity under test. Record Sensor width before the first frame and confirm Lens shift from the same lens state. For Shift Lens Coverage, note the marked focal length and focus state beside Sensor width; internal focusing or zoom position can change the effective geometry.
After the published Shift Lens Coverage baseline, create a second case that changes only Lens shift by a measurable amount. A doubled distance, one-stop aperture change, known crop, measured rail movement, or fixed pixel dimension gives required image circle an independent directional expectation.
For Shift Lens Coverage, inspect both center and edge when using required image circle; projection, coverage, vignetting, distortion, diffraction, or field curvature may vary across the image. A center-frame Shift Lens Coverage measurement may agree while the edge departs because of behavior outside this simplified equation.
Using required image circle in a shooting decision
For Shift Lens Coverage, translate the number into one concrete choice: move the camera, change focal length, select an aperture, set a rail position, confirm image-circle coverage, or decide whether the subject will occupy enough pixels. Keep that action beside the saved required image circle so another person knows why the calculation was made.
If required image circle falls between marked Shift Lens Coverage controls, retain the unrounded value and document the setting actually used. Test the neighboring available Lens shift value instead of claiming more adjustment precision than the lens, rail, focus scale, tilt mechanism, or camera position provides.
For Shift Lens Coverage, after the photograph, compare the recorded frame with the expected required image circle. Save deviations that repeat across tests; they can reveal focus breathing, a nominal sensor dimension, an entrance-pupil offset, a lens-specific projection, or another stable correction worth applying in future Shift Lens Coverage work.
Questions about shift lens coverage calculator
What does Shift Lens Coverage Calculator calculate?
It calculates required image circle from Sensor width, Sensor height, Lens shift. Calculate required image-circle coverage from sensor size and shift.
Which measurement should I verify first?
Confirm Sensor width, its unit, and its reference plane before using the other entries.
What is the main limitation?
Shift direction matters; this model applies the entered shift along sensor width.
How can I check required image circle?
Run the defaults, change only Lens shift, predict the direction, and restore the starting value.