Sensitivity factors include: Light collection (∠NA²), Objective transmittance, Magnification effect (photons per pixel ∠1/Mag²), Pixel area (larger pixels collect more light), and QE. A 25× 1.1NA system with 3.7μm pixels can match a 60× 1.2NA system with 6.5μm pixels because: lower magnification concentrates more photons per pixel, larger sample area per pixel compensates for slightly lower NA².
Comparison Metric
Equivalent Sensitivity
How different systems achieve similar performance
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Definition
The principle that different camera/objective combinations can achieve similar practical sensitivity through compensating factors. A system with lower QE or smaller NA can match a 'better' system if other parameters compensate.
Technical Details
Simplified
A less expensive camera with a different objective can take equally good pictures as a more expensive system, because the factors that determine how much light each pixel gets can balance out in different ways.
Why It Matters
Understanding equivalent sensitivity prevents over-specifying expensive components. A 5× E9 system at 25× can match a 3× Kinetix system at 60× for sensitivity while providing better throughput and lower cost.
Practical Example
E9 (3.7μm, 91% QE) at 25× vs Kinetix (6.5μm, 95% QE) at 60×: The E9's larger sample area per pixel (148nm vs 108nm) largely compensates for the Kinetix's advantages in QE and sensor area, while providing 5× more sample area per frame.