Datasheet

B+W Filter –
quality without rough
edges for optical
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Threaded fi lter mounts.
The quality of high-grade fi lters is determined by various crite-
ria. Many photographers are aware that the plane parallelism
and transmission properties of glass and the coating are key
factors for image quality. What fewer of them know is that the
fi lter mount must also meet high requirements as a link in the
high-tech chain. The main purpose of the mount is to hold the
fragile fi lter glass in place, fi rmly yet without play, for a long
time. However, the glass must not be subjected to mechanical
tension because even the tiniest deformations can result in
visible unsharpness. Nevertheless, the fi lter must also be able
to withstand a strong grip. And even after frequent use it must
ensure easy and precise attachment and removal. A non-slip
surface quality makes handling easier. The mount thickness
should be kept to a minimum in order to prevent vignetting at
short focal lengths.
B+W fi lter mounts meet these requirements to perfection.
As a rule, they are made of brass on highly accurate CNC
machines. The fi lter glass is kept in place securely but without
tension by a threaded retaining ring that is manufactured with
equal accuracy. Fine grooving (knurling) on the front makes
attachment easier. Black (or silver) hard-chrome plating, clearly
legible labeling (and usually matte black inside surface) ensure
lastingly stable image quality and functionality.
To avoid vignetting in the image corners at extreme wide
angles despite the slim design, B+W provides various mount
types that cater for the different angles of view.
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