5σ sensitivity limits in terms of apparent magnitude in the 4.5 μm band, for the targets ϵ Eri (blue, solid line), Fomalhaut (green, dash-dotted line), and Vega (red, dashed line). Since Vega is brighter than the two other targets, it is less sensitive to very faint companions due to the bright PSF wings. Fomalhaut is slightly brighter than ϵ Eri, but since a larger amount of data is accessible for the case of Fomalhaut (see Sect. 4.2), the contrast performance is increased, and so for the inner parts of the separation range an approximately equal performance is attained for those two targets.