Lensing observational status. M₅₀₀–z plane with symbol colours representing the depth of the archival or dedicated lensing data. Shallow surveys like CFIS (and more so, DES, KiDS) yielding a density of background sources n ≲ 10 arcmin⁻² cannot probe the low mass end of Tier-1 clusters with S/N > 3. Stacking of the shear signal will be unavoidable for these. Deep Subaru data enable such measurements on individual clusters since most observations reach source densities ≳20 arcmin⁻². Euclid, which will reach n ≃ 30 arcmin⁻² will greatly simplify cluster mass calibrations with lensing.