Concave vs Convex Lens

Convex (converging) lens — thicker in the centre. Parallel rays converge at the focal point, f > 0. Used in cameras, magnifying glasses, hyperopia (farsighted) correction, microscope objectives, and reading glasses.

Concave (diverging) lens — thinner in the centre. Parallel rays diverge as if from the focal point, f < 0. Used in myopia (nearsighted) correction, Galilean telescopes, and beam expanders.

Both obey the thin-lens equation 1/s + 1/s′ = 1/f and the lensmaker's equation 1/f = (n − 1) (1/R₁ − 1/R₂). Image type (real/virtual, upright/inverted, magnified/diminished) follows from the sign of f and the object distance relative to f.

Recent research on this topic from arXiv

Preprints and papers indexed on arXiv.org. Links open the public abstract pages.

Physical Cue based Depth-Sensing by Color Coding with Deaberration Network
Nao Mishima, Tatsuo Kozakaya, Akihisa Moriya et al. · 2019 · arXiv:1908.00329v1
Color-coded aperture (CCA) methods can physically measure the depth of a scene given by physical cues from a single-shot image of a monocular camera. However, they are vulnerable to actual lens aberrations in real scenes because they assume...
Two families of astrophysical diverging lens models
Xinzhong Er, Adam Rogers · 2017 · arXiv:1712.06900v1
In the standard gravitational lensing scenario, rays from a background source are bent in the direction of a foreground lensing mass distribution. Diverging lens behaviour produces deflections in the opposite sense to gravitational lensing,...
An Analysis of Optical Contributions to a Photo-Sensor's Ballistic Fingerprints
Richard Matthews, Matthew Sorell, Nickolas Falkner · 2018 · arXiv:1808.08684v2
Lens aberrations have previously been used to determine the provenance of an image. However, this is not necessarily unique to an image sensor, as lens systems are often interchanged. Photo-response non-uniformity noise was proposed in 2005...
Exploiting lens aberrations to create electron vortex beams
L. Clark, A. Béché, G. Guzzinati et al. · 2013 · arXiv:1305.5463v2
A model for a new electron vortex beam production method is proposed and experimentally demonstrated. The technique calls on the controlled manipulation of the degrees of freedom of the lens aberrations to achieve a helical phase front. The...

Recent research on this topic from arXiv

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