Archived posting to the Leica Users Group, 1999/06/28
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Gregoire,
A floating optic is usually one lens or a lens group that changes position
(forward or backward) as the lens is focussed from distance to near. It is
done to improve imaging performance at closer focussing distances and
usually decreases curvature of field. This lens design is a recent addition
to Leica lenses (perhaps in the last eight years). For a long time, Leica
chose not to include this option. Perhaps the design team felt that real
world imaging was not that of photographing flat surfaces but real objects
that didn't really need optimal flat field imaging. I don't know what the
optical design gives up with floating elements. Usually there is give and
take with optical design and when you gain one thing you sometimes
compromise another.
I hope this is helpful.
Richard Clompus, OD
Innotech
Johnson & Johnson Vision Products
Virginia, USA
- -----Original Message-----
From: Grégoire Vandenschrick [mailto:vandenschrick@geog.ucl.ac.be]
Sent: Monday, June 28, 1999 9:38 AM
To: Leica User Group
Subject:
Is there someone who can explain me what is a floating element, in optic.
thank you
Gregoire Vandenschrick, Assistant de recherche
Unite GEOG, Departement GEO, Faculte des Sciences
Universite catholique de Louvain
email: vandenschrick@geog.ucl.ac.be <mailto:vandenschrick@geog.ucl.ac.be>
vandenschrick@page.ucl.ac.be <mailto:vandenschrick@page.ucl.ac.be>
Tel: (00 32) 10 47 28 42
Fax: (00 32) 10 47 25 56
prive: (00 32) 2 762 06 22
Adresse postale:
Bureau b365, Etage b3, Batiment Mercator
3, Place Louis Pasteur
1348 Ottignies - Louvain-la-Neuve