Sensor Crop and Focal Length: The Complete Reference Table for Every Major Camera

The Wrong Lens on the Wrong Camera

A DP confirms a 35mm prime as the establishing wide for a feature. The camera is listed as ARRI ALEXA 35 in Super 35 mode in the prep documents. Four days before the shoot, the director switches to a Sony FX9. The DP doesn't recalculate.

The FX9 has a full-frame sensor (35.7 x 23.8mm). The same 35mm lens that covered the building facade at 46 degrees horizontal on the ALEXA 35 Super 35 mode now covers 54 degrees on the FX9. The establishing shot cuts off the left wing. Moving the camera back to restore the framing puts it in the street -- which requires a permit the production doesn't have.

Crop factor is not a theoretical concern. It changes what your lens sees, and it changes practically any time the camera body changes. This table is the reference to check before the lens order is placed.

How Crop Factor Works

Focal length equivalence is a geometric relationship between sensor size and angle of view. The physics are described in detail by the ASC Manual (11th Edition) and in Zeiss's published optics documentation, but the practical formula is straightforward:

Effective Crop Factor = Super 35 Reference Width / Actual Sensor Width

Super 35 is the cinema industry reference standard. It corresponds approximately to a 4-perf 35mm film frame. Most lens characteristics in cinema are described relative to Super 35.

A crop factor of 1.0x means the sensor matches Super 35 and the lens produces the field of view its focal length implies. A crop factor below 1.0x (large format, full frame) means a larger sensor: the lens covers a wider angle of view. A crop factor above 1.0x (Micro Four Thirds, smaller sensors) means a smaller sensor: the lens covers a narrower angle of view, "cropping in" on the image circle.

A 50mm lens on an MFT sensor (1.88x crop) produces the same horizontal field of view as a 94mm lens on Super 35. The optical properties of the 50mm glass haven't changed -- the sensor simply uses a smaller portion of the image circle it projects. A detailed treatment of the geometry of focal length equivalence is in Sidney Ray's Scientific Photography and Applied Imaging (Focal Press), a standard optics reference used in ASC curriculum.

Use the Crop Factor Comparison tool to calculate the effective focal length of any lens on any sensor in the table below.

The Complete Reference Table

Cinema Cameras

Hybrid and Documentary Cameras

Sensor dimensions are manufacturer-published active image area figures as of early 2026. Cameras with multiple crop modes show the primary or default recording mode. Always verify the active sensor area for the specific recording mode in use.

What Crop Factor Changes in Practice

Field of view: A 50mm lens on the BMPCC 4K (MFT, 1.88x crop) gives the same horizontal angle of view as a 94mm on Super 35. A 50mm on the ARRI ALEXA LF (0.74x) gives approximately the same angle as a 37mm on Super 35. The same glass, entirely different coverage. Use the Field of View Calculator to model this before ordering lenses.

Depth of field: Smaller sensors produce greater depth of field at the same f-stop and equivalent subject framing. To match the depth of field on a BMPCC 4K that you would get on a Super 35 camera at f/2.8, you need to open to approximately f/1.5. This matters on run-and-gun and documentary work where shallow depth of field is a deliberate choice. The Depth of Field Calculator handles cross-sensor DoF comparison correctly.

Lens image circle coverage: Cinema lenses are designed for specific image circles. A Super 35 PL lens may not cover a full-frame or large format sensor. The crop factor table identifies which combinations will produce vignetting. Confirm image circle coverage against the manufacturer's specifications before renting glass for a large format body.

Three Production Scenarios

Scenario 1: Matching the "Natural Perspective" Across Bodies

A director asks for a "50mm feel" -- natural perspective, minimal distortion, approximating the human visual field. On Super 35, a 50mm prime delivers this. On the Sony FX9 (0.73x full frame), matching the same field of view requires a 37mm. On a BMPCC 4K (1.88x MFT), the equivalent is a 27mm. Ordering "50mm" as the natural-look lens without checking the sensor produces a noticeably different frame on each body.

Scenario 2: Multi-Camera Productions with Mixed Sensor Sizes

An ARRI ALEXA 35 (Super 35, A-camera) and a Sony FX9 (full frame, B-camera) shoot the same scene for cutaway coverage. The A-camera uses a 35mm for principal coverage. To match the field of view on the FX9 (0.73x crop), the FX9 needs a 25mm. Ordering matching 35mm lenses for both cameras produces coverage that doesn't cut together. The Crop Factor Comparison calculates the required lens for any cross-camera match.

Scenario 3: Vintage Glass on a Large Format Body

A DP rehouses a set of Super 35-era Zeiss Standard Speeds for a large format shoot on the ARRI ALEXA LF. The 18mm that was an ultrawide on Super 35 is now equivalent to approximately a 13mm on the large format sensor -- a different focal length class entirely. More importantly, the 18mm Zeiss Standard Speed has an image circle of approximately 28.5mm, which doesn't cover the ALEXA LF's 36.70mm sensor width. Vignetting appears before the question of focal length equivalence matters. Verify image circle coverage first, then calculate the effective focal length.

Pro Tips and Common Mistakes

Pro Tip: Always specify the sensor format alongside the focal length in shot lists and director's treatments. "35mm" is incomplete. "35mm on Super 35" is a complete specification. When the camera body changes during production -- and it does more often than anyone plans for -- the format specification prevents the lens order from being based on the wrong assumption.

Pro Tip: The Sony VENICE 2, ARRI ALEXA 35, and RED V-RAPTOR XL all offer multiple crop modes with different active sensor areas. Specify which mode is being used in the camera report and on the shot list. A PL lens that covers the Super 35 crop mode may vignette in full frame mode on the same body.

Common Mistake: Treating the BMPCC 4K's 1.88x crop factor as equivalent to any other Super 35 camera. Filmmakers accustomed to Super 35 or full frame lenses frequently underestimate how significantly the 1.88x multiplier narrows their ultrawide options. A 12mm on MFT gives the same horizontal field as a 22mm on Super 35. There is no native MFT prime that replicates a 10mm on Super 35 without a dedicated ultrawide, and very few exist in the cinema PL ecosystem.

The fix: When shooting on MFT, calculate every lens in the kit using the 1.88x multiplier before the lens order is confirmed. Any focal length below 18mm on MFT is in a range where native coverage becomes limited.

Common Mistake: Assuming the Sony A7S III's crop factor is constant across all recording modes. At standard 4K recording, the A7S III uses its full-frame sensor (0.73x). At 4K above 120fps, it crops to APS-C, changing the effective crop to approximately 1.05x. The same 24mm lens that covers a wide establishing shot in full-frame mode produces a noticeably tighter frame in the high-speed crop mode. Check the manufacturer's specification table for the active sensor area in each recording mode before finalizing the lens list for high-frame-rate sequences.

Frequently Asked Questions

Why is Super 35 the reference instead of full-frame 35mm?

Super 35 has been the dominant sensor format in cinema since the film era and became the default for digital cinema cameras in the mid-2000s. Full frame (35mm stills format) is a larger sensor that is now common in hybrid and cinema bodies, but the industry calibrated focal length expectations against Super 35 -- which is why a 35mm is described as a "standard" cinema lens rather than the 50mm standard in still photography. Using Super 35 as the reference keeps crop factor descriptions consistent with how cinematographers discuss focal length in professional practice.

Does crop factor affect lens optical quality?

Crop factor changes which portion of the image circle the sensor uses, not the optical properties of the glass itself. A lens that is sharp at center but softer at the corners on a full-frame sensor may appear sharper on a Super 35 sensor that uses only the center of the image circle. Conversely, a lens optimized for full-frame coverage may not deliver its best performance on a Super 35 crop. These differences are typically minor but matter when selecting vintage glass originally designed for a specific sensor format.

How do I convert if a reference uses full-frame 35mm stills instead of Super 35?

Super 35 has a crop factor of approximately 1.39x relative to full-frame 35mm stills. A 50mm on Super 35 is equivalent to approximately 70mm on a full-frame stills sensor. This is why "50mm looks natural" holds in photography (using full-frame reference) while "35mm" is the natural-perspective lens in Super 35 cinema production.

Does frame rate affect crop factor?

On most cameras, no. But some cameras reduce the active sensor area at high frame rates. The Sony A7S III crops from full frame to APS-C above 120fps in 4K. The Sony FX9 applies a slight crop in several high-speed modes. Always verify the active image area in the manufacturer's recording format specification sheet for the specific mode being used before confirming the lens list for high-frame-rate setups.

How do I verify image circle coverage before renting a lens?

Lens manufacturers publish image circle diameter in their technical specifications. Cooke Optics, Zeiss, and Leica all include this in their downloadable lens data sheets. Compare the published image circle to the sensor's diagonal dimension. If the image circle diameter is smaller than the sensor diagonal, the lens will vignette at the sensor's corners in that format. Zeiss's published lens data is available at zeiss.com/consumer-products and includes cinema glass specifications.

Related Tools

The Crop Factor Comparison tool calculates the effective focal length of any lens on any sensor in the tables above. The Field of View Calculator uses crop factor and focal length together to output frame width and height at a specific shooting distance. The Depth of Field Calculator accounts for sensor size in its DoF output, which is required when comparing depth of field across different sensor formats.

Check the Sensor Before the Lens Order

Crop factor is a production planning variable, not a post-production discovery. It determines which lens produces the frame you scouted, which lenses in an existing kit transfer to a new body, and whether coverage shot on the A-camera matches coverage shot on the B-camera. When the sensor is confirmed and the crop factor is known, the correct lens for every setup can be specified precisely -- and the wrong one stays off the truck.

What was the most expensive crop factor mistake you've encountered mid-production, and which camera combination caused it?