Also since multiple surfaces are involved, creating a design with good aberration correction can be very complex.
It incorporates a special low dispersion glass and two aspherical lens elements to provide aberration corrections combined with superior image quality.
Optically, non-compact designs often yield better aberration correction and a flatter field than a compact design, but at the expense of longer tube length.
And the automatic chromatic aberration correction is impressive.
As maximum aperture continued to increase, the Double Gauss's greater symmetry promised easier aberration correction.
If red, green and blue are brought to a common focus (plus other aberration corrections) with very little residual aberration, the lens is called apochromatic.
These elements can be both lenses and mirrors, but since multiple surfaces are involved, achieving good aberration correction in these systems can be very complex.
Both the Olympus and Canon show no noise, while the XZ-1's lens appears to have better aberration correction in the corners.
Also since the light passes through the corrector twice, the number of surfaces involved is multiplied, making it difficult to achieve good aberration correction.
Modern optical design techniques have enabled the construction of zoom lenses with good aberration correction over widely variable focal lengths and apertures.