Why laser phase plate datasets yield worse SPA resolution than defocus datasets

Determine why single‑particle analysis reconstructions using laser phase plate datasets exhibit consistently worse resolution than defocus‑only datasets despite markedly higher low‑frequency contrast, and characterize how contrast distribution across spatial frequencies influences particle alignment and reconstruction accuracy.

Background

Comparative SPA tests on RuBisCO and apoferritin show that laser phase plate datasets, though richer in low‑frequency contrast, produce slightly worse resolutions and/or less favorable ResLog metrics.

The authors note this inconsistency is not explained by phase‑shift instability or Volta phase plate losses and suspect algorithmic bias from enhanced low‑frequency content. Resolving this will clarify when and how LPP can benefit SPA.