is of the widest part of the eyepiece including any protruding knurled grip area and not just
the plain casing of the eyepiece. This is the part of the eyepiece that goes into the
eyepiece clamp of the AF51. Some examples are illustrated in figure 5.2. Note that this
measurement only determines if the body of the eyepiece can fit and be held into the
standard eyepiece clamp of the AF51. The fact that an eyepiece can fit into the clamp
does not necessarily mean it will be useable with the AF51 camera with this clamp
because that will also depend on the level of the eye point of the lens. This will be
discussed in a later section.
Figure 5.2 Examples of eyepiece maximum outer diameter (in mm) for three eyepieces.
Left
: Zeiss W Kpl
x10,
Middle
: OptArc WF x10/20,
Right
: Celestron X-Cel LX 18 mm. Maximum body diameter measurements
are shown above each eyepiece (units are mm). The Zeiss will be too small to fit the standard AF51
eyepiece clamp without a special adapter (not supplied). The Celestron will be too large to fit. See text for
details.
The standard clamp mechanism of the AF51 was designed to work optimally for
eyepieces with a maximum outer diameter of 35 mm to 36.5 mm. However it will
work with eyepieces that have a maximum outer diameter in the range 33 mm to
37.5 mm (inclusive) but the upper end of that scale needs special attention
(detailed below). For eyepieces with maximum outer diameters outside this
range, custom adapters need to be used (these adaptors are not supplied with
the AF51).
Examples of eyepieces with a maximum outer diameter in the range 35 mm to 36 mm
include the OptArc x10/20 WF, the Leica L Plan x10/20 (including the ‘M’ variant), the
Olympus SWHK 10xL and Olympus WHK 10x/20 L.
Eyepieces with a maximum diameter in this range should be useable even when the
clamp sheath fold connections have broken and the folds protrude into the clamp
OptArc AF51 Camera Page 50 of 99 User Guide v1.02
