Beyond lensing by the cosmological constant

The long-standing problem of whether the cosmological constant affects directly the deflection of light caused by a gravitational lens is reconsidered. We use a new approach based on the Hawking quasilocal mass of a sphere grazed by light rays and on its splitting into local and cosmological parts. Previous literature restricted to the cosmological constant is extended to any form of dark energy accelerating the universe in which the gravitational lens is embedded.