Format match
{{ targetLensLabel }}
{{ equivalenceDetail }}
{{ directionBadge.label }} {{ sourceCropLabel }} {{ targetCropLabel }} Exposure separate
{{ visualScene.sourceLabel }} {{ visualScene.targetLabel }} {{ visualScene.sourceMarker }} {{ visualScene.targetMarker }} {{ visualScene.ratioMarker }}
Start from APS-C, Micro Four Thirds, Super 35, full-frame, medium-format, or compact-camera examples.
Pick the body or crop mode you want to match from.
Use the active image area after still/video mode crops.
x mm
Target focal length and depth-of-field look are calculated for this format.
Use the target active image area after still/video mode crops.
x mm
This value is the physical lens marking on the source camera.
mm
Equivalent aperture is a depth-of-field look comparison; it is not an exposure multiplier.
f/
Leave at 1.0 for stills, open-gate, or uncropped video.
x
Set the target crop if you are matching a video mode, stabilizer crop, or open-gate extraction.
x
Choose the common focal-length list closest to the target kit you are planning around.
{{ formatPlainNumber(match_tolerance_percent, 0) }}%
A smaller value is stricter about whether a real lens is close to the exact target focal length.
MetricValueDetailCopy
{{ row.metric }} {{ row.value }} {{ row.detail }}
Format itemSourceTargetNoteCopy
{{ row.item }} {{ row.source }} {{ row.target }} {{ row.note }}
Target lensFrame readAperture targetMatch statusUse cueCopy
{{ row.target_lens }} {{ row.frame_read }} {{ row.aperture_target }} {{ row.match_status }} {{ row.use_cue }}
Tags: Education, Photography, Videography
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Lens equivalence compares how a lens frames a scene when the active image area changes. A 35 mm lens records a wider view on full frame than it does on APS-C because the smaller format captures a narrower rectangle from the same projected image. Crop factor gives that difference a common language, usually by comparing each format's diagonal against the 36 x 24 mm full-frame reference.

Photographers and filmmakers use equivalence when they switch camera systems, mix bodies on one shoot, translate a stills lens list into a cinema format, or check whether a video crop will make a wide lens too tight. The practical questions are usually simple: what physical focal length on the target format gives similar framing, and what f-number gives a similar depth-of-field look?

Two sensor rectangles connected by a lens scaling arrow for format equivalence

Equivalent aperture needs extra care. It describes comparable depth of field and blur appearance after the framing is matched; it is not an exposure multiplier. A lens set to f/1.8 meters as f/1.8 on its camera. If the matching target look lands near f/2.8 and you actually set the target lens to f/2.8, the exposure changes because the target lens is now physically stopped down.

Equivalence also does not make perspective, bokeh character, lens transmission, focus breathing, or aspect ratio identical. It is a planning estimate for field of view and depth-of-field appearance, strongest when subject distance, focus distance, framing, and active recording area are known.

How to Use This Tool:

Start with the setup that best matches the lens you already know, then adjust the target format until the summary and tables describe the match you want to shoot.

  1. Pick a Setup preset such as APS-C to full frame, Micro Four Thirds to full frame, Super 35 cinema to full frame, or choose Custom edited setup when none of the examples is close.
  2. Set Source format to the camera or recording format where the lens is currently used. If you choose Custom sensor, enter the active width and height in millimeters.
  3. Set Target format to the camera, sensor mode, or crop mode you want to match. Use the custom target dimensions when the active image area is known from a spec sheet or production note.
  4. Enter the Source focal length printed on the lens and the actual Source aperture selected on the camera. Do not enter a full-frame equivalent focal length here.
  5. Add Source extra crop or Target extra crop for 4K crops, digital stabilization, active extraction, or any recording mode that uses less than the selected format.
  6. Choose the Target lens set closest to the kit you are planning around, then use Close-match tolerance to make the lens candidate labels stricter or more forgiving.
  7. Read the summary first, then check Match Brief for the target focal length and depth-of-field look, Format Ledger for crop factors and active sensor sizes, Lens Match Table for real focal-length candidates, and Format Match Map for a cross-format comparison.

If the Check the lens setup alert appears, correct the highlighted value before interpreting the results. Common fixes are a source focal length greater than 0 mm, a source aperture of f/0.7 or slower, positive custom sensor dimensions, and extra crop values of 1.00x or greater.

Interpreting Results:

The most important number is Target focal length. It is the physical focal length to look for on the target format, not another equivalent label. If it says 53.7 mm on full frame, a 50 mm or 56 mm lens may be close enough depending on the tolerance and the composition.

Depth-of-field look is the f-number that gives a similar blur comparison after the field of view is matched. The Exposure note keeps the metering point separate, because setting a target lens to the equivalent f-number changes brightness in the normal exposure sense.

The Lens Match Table labels candidate lenses against the exact target focal length. With the default 8% tolerance, Close match means the candidate is within 8% of the exact target, Practical substitute means it is more than 8% but no more than 20% away, and Different framing means the candidate should be treated as a composition change rather than a direct match.

Do not overread a perfect-looking number. Verify the Diagonal crop factor and Extra crop rows in the Format Ledger, especially for video modes. Then check whether the suggested f-number and nearest real lens in the target kit are actually available for the shot.

Technical Details:

Crop factor is based on image-area geometry. The full-frame reference is 36 x 24 mm, with a diagonal of about 43.27 mm. Smaller active image areas have larger crop factors because their diagonals are shorter; larger formats such as 44 x 33 mm medium format have crop factors below 1 because their diagonals are longer.

For matching between two non-full-frame formats, the calculation does not need to convert everything into a full-frame lens first. It compares the source crop factor with the target crop factor. The same source-to-target multiplier is applied to focal length and to the depth-of-field f-number, while exposure remains tied to the actual aperture used on the lens.

Formula Core

The active image diagonal is calculated from the format width and height:

d = w2 + h2

Crop factor then compares that diagonal with the full-frame diagonal and multiplies any extra recording crop:

C = 43.27 mm d × E

The source-to-target multiplier is the ratio of the two effective crop factors:

R = Csource Ctarget

Target focal length and depth-of-field equivalent aperture use that same multiplier:

Ftarget = Fsource × R Nlook = Nsource × R

When the equivalent look aperture is compared with the source aperture, the exposure difference in stops follows the usual f-number stop relationship:

stops = 2 × log2 ( Nlook Nsource )
Symbol Meaning Visible input or output
w, h Active image width and height in millimeters. Selected format dimensions or custom sensor dimensions.
E Extra crop applied by a recording mode or extraction. Source extra crop and Target extra crop.
C Effective diagonal crop factor after extra crop. Diagonal crop factor in Format Ledger.
R Source-to-target scale used for matching. Match multiplier in Format Ledger.
F Physical focal length in millimeters. Source focal length and Target focal length.
N F-number for aperture comparison. Source aperture and Depth-of-field look.

Format Reference

The built-in format choices use common active-frame dimensions. Custom formats use the dimensions you enter, which is useful when a camera mode crops the sensor differently from its still-photo specification.

Format Active size Approx. crop factor Typical use
44 x 33 medium format 44.0 x 33.0 mm 0.79x Larger-than-full-frame stills reference.
Full frame / 35mm 36.0 x 24.0 mm 1.00x Common comparison baseline.
APS-C 1.5x 23.5 x 15.6 mm 1.53x Many Nikon, Sony, Fujifilm, Pentax, and similar APS-C bodies.
Canon APS-C 1.6x 22.3 x 14.9 mm 1.61x Canon crop-sensor stills bodies.
Super 35 cinema 24.9 x 18.7 mm 1.39x Cinema-style framing reference.
Micro Four Thirds 17.3 x 13.0 mm 2.00x Mirrorless stills and compact video setups.
1-inch type 13.2 x 8.8 mm 2.73x Compact cameras and some small cinema or video cameras.
2/3-inch video 8.8 x 6.6 mm 3.93x Broadcast-style video formats.

Candidate Lens Rules

Candidate lenses are compared against the exact target focal length, not against the source lens marking. The close-match tolerance controls the labels in the Lens Match Table.

Match status Boundary Meaning
Close match Difference <= tolerance The candidate is close enough to use first if the listed frame read is acceptable.
Practical substitute Tolerance < difference <= 2.5 x tolerance The candidate may work if you can crop, step back, or accept a changed frame.
Different framing Difference > 2.5 x tolerance The candidate should be treated as a different composition.

Worked Mechanism Path

A 35 mm f/1.8 source lens on 23.5 x 15.6 mm APS-C has a diagonal crop factor near 1.53x. Matching it to full frame gives a source-to-target multiplier near 1.53, so the target focal length is 35 x 1.53 = 53.7 mm and the depth-of-field look is f/1.8 x 1.53 = f/2.8. The physical source lens is still a 35 mm f/1.8 lens, and a target lens set to f/2.8 is metered as f/2.8.

Accuracy and Privacy Notes:

The calculation is deterministic, but lens equivalence is still an estimate of visual similarity. It does not model exact lens rendering, focus breathing, T-stop transmission, adapter optics, macro pupil magnification, stabilization crops that vary by mode, or how a different aspect ratio changes horizontal and vertical framing.

  • Use actual active recording dimensions when the camera mode crops differently from the body format name.
  • Custom sensor dimensions are intended for positive values from 1 mm to 80 mm in each direction.
  • Depth-of-field comparison assumes similar framing and focus distance; changing subject distance changes perspective and blur.
  • No image, EXIF file, or camera file is uploaded. Entered lens and sensor values are used in the browser to calculate the tables and chart.

Worked Examples:

APS-C portrait matched to full frame. Choose APS-C 1.5x as the source, Full frame / 35mm as the target, enter 35 mm and f/1.8, and leave both extra crops at 1.00x. Target focal length reads about 53.7 mm and Depth-of-field look reads f/2.8 look. In the Lens Match Table, 50 mm and 56 mm candidates sit close to the exact value, so the final choice depends on whether a slightly wider or tighter frame fits the subject.

Micro Four Thirds video with an extra crop. A 12 mm f/2.8 source on Micro Four Thirds normally frames near 24 mm on full frame. If the recording mode adds a 1.25x source crop, Format Ledger shows a smaller active source area and a larger effective crop factor, so Target focal length moves to about 30.0 mm and Depth-of-field look moves to about f/7.0. That is a wide-angle framing match, not an instruction to meter the original lens as f/7.

Full-frame portrait moved to Micro Four Thirds. An 85 mm f/1.8 source on full frame maps to about 42.5 mm on Micro Four Thirds and about f/0.9 for the same depth-of-field look. A 40 mm target lens can be a Close match with the default tolerance, while a 50 mm lens is more likely a Practical substitute. If f/0.9 is not available, the framing can still be matched, but the target setup will show deeper depth of field.

Custom setup error recovery. If a custom sensor width is left at 0 or the source focal length is cleared, the Check the lens setup alert appears before the comparison should be trusted. Enter positive sensor dimensions and a source focal length greater than 0 mm, then recheck Match Brief and Format Ledger before using the candidate lens list.

FAQ:

Does equivalent aperture change exposure?

No. Depth-of-field look compares blur appearance after matching framing. Exposure is still based on the actual f-number set on the lens, which is why Exposure note calls out the metering difference separately.

Should I enter the lens marking or the full-frame equivalent?

Enter the physical lens marking in Source focal length. A 35 mm APS-C lens should be entered as 35 mm, not as its full-frame equivalent, because the crop factor is applied by the comparison.

How should video crops be handled?

Use Source extra crop or Target extra crop when a video mode, digital stabilizer, or extraction uses less than the selected format. The Active sensor and Diagonal crop factor rows show how that extra crop changed the comparison.

What does Close match mean?

Close match means the candidate focal length is within the current Close-match tolerance of the exact target focal length. Raising the tolerance makes more lenses count as close; lowering it makes the label stricter.

Why is the Format Match Map unavailable?

The map can be unavailable when the page cannot draw the chart or when the setup has validation errors. Use Lens Match Table and Format Ledger for the same equivalence data, then fix any alert values before checking the chart again.

Does the comparison upload my camera or lens data?

No image, EXIF file, or camera file is uploaded. The entered focal length, aperture, sensor dimensions, crop settings, and tolerance are used in the browser to calculate the visible results.

Glossary:

Crop factor
The ratio between the full-frame diagonal and the active image diagonal, after any extra crop is applied.
35mm equivalent focal length
The focal length on a 35 mm film or full-frame camera that gives a similar angle of view.
Equivalent aperture
The f-number used to compare depth-of-field look across matched formats, separate from exposure metering.
Extra crop
An additional reduction in active image area from video mode, stabilization, or extraction beyond the chosen format.
Diagonal
The corner-to-corner distance across the active image area, used here as the basis for crop factor.
F-number
The focal length divided by the effective aperture diameter, shown as values such as f/1.8 or f/2.8.

References: