Ranking methodology · Version 1.1

The score is calculated. The interval is judgment.

Every rank begins with lens-specific optical evidence. The workflow keeps unlike test systems separate, weights fine-detail transfer most heavily, and widens uncertainty when the evidence becomes less comparable.

The question being measured

The Resolution Index estimates how confidently a lens can deliver high spatial detail across the APS-C image field. It is not an overall product score. Autofocus, stabilization, sealing, close focus, size, rendering, and value remain important, but they appear in the written verdict rather than inflating optical resolution.

Fujifilm maker-chart calculation

MAKER MTF INDEX0.25 × AUC₁₅ + 0.55 × AUC₄₅ + 0.15 × EDGE₄₅ + 0.05 × S/M

Digitize all four curves.
The sagittal and meridional curves at 15 and 45 lines/mm are sampled from the optical center to the published edge. The area under each curve is normalized to a 0–100 scale.
Emphasize fine detail.
The 45 lines/mm curves receive 55% of the weight. Low-frequency contrast at 15 lines/mm still matters, but it cannot dominate the score.
Protect the outer field.
The outer 20% of the 45 lines/mm curve receives a separate 15% term so exceptional central sharpness cannot conceal a weak edge.
Penalize sagittal/meridional separation.
The final 5% rewards agreement between curve orientations. Divergence is treated as evidence of astigmatism or uneven detail rendering, not as an automatic artistic defect.
Apply a diffraction ceiling.
Published geometrical curves do not show the real diffraction loss imposed by the stated maximum aperture. A circular-aperture MTF at 550nm limits the achievable transfer, preventing a slow theoretical curve from defeating a faster lens on geometry alone.

Evidence hierarchy

AComparable controlled testMeasured resolution on an identified camera, aperture, focal length, and test protocol.

BLens-specific maker MTFOfficial sagittal and meridional curves, interpreted within that maker’s chart system.

CMultiple technical reviewsAt least two independent sources with resolution crops, charts, or repeatable field comparisons.

DSupported owner consensusRepeated, technically credible observations used only when stronger evidence is unavailable.

—Data pendingMarketing claims or one unsupported opinion are not enough to force a lens into the ladder.

Combining evidence without mixing rulers

Raw MTF values from different manufacturers are not treated as if they came from the same instrument. Likewise, a laboratory result from one sensor, demosaicing pipeline, sharpening setting, or chart distance is not directly compared with an unrelated test.

Results are first normalized inside a compatible cohort. When a Fujifilm maker chart and a compatible controlled test both exist, the current index combines 55% normalized maker evidence and 45% controlled-test or technical prior. Laboratory-only results remain inside their own camera-and-method cohort before being mapped to the common index.

Confidence and tie-breaking

The displayed ± interval is an uncertainty band, not a conventional statistical confidence interval. It expands for unmatched test systems, single samples, zoom endpoint variation, focus-sensitive designs, and review-derived estimates. It contracts when controlled testing and independent sources agree.

If score intervals overlap, the lenses are treated as optically tied. The tie-break order is: stronger controlled evidence, better outer-field behavior, smaller sagittal/meridional separation, then agreement across multiple technical reviewers. Popularity, price, and brand do not break an optical tie.

Why the XF 200mm F2 ranks first

Its official curve averages approximately 97% at 15 lines/mm and 84% at 45 lines/mm, retains about 80% at the outer field, and shows approximately 98% sagittal/meridional agreement. Its diffraction-adjusted Maker MTF Index is 82.9. The XF 500mm F5.6 produces a higher theoretical maker-only index, but the XF 200mm F2 adds controlled-laboratory confirmation and three corroborating sources, producing the tighter evidence-adjusted result.