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Reference
Banner Engineering Corp.
• Minneapolis, MN U.S.A.
www.bannerengineering.com • Tel: 763.544.3164
Appendix A: Selecting a Lens
Types of Lenses
Any user-supplied C-mount style lens may be used.
Lenses may also be purchased through Banner (visit
Banner’s web site at www.bannerengineering.com);
three choices include:
• 8 mm (8 mm focal length) LCF08
• 12 mm (12 mm focal length) LCF12
• 16 mm (16 mm focal length) LCF16
Lens Selection Criteria
To select the best lens for any application, consider
the following lens performance criteria:
• Size of the inspection area (field of view)
• Lens-to-object distance, and any distance variation
between the sensor and the object (depth of field)
• Required sensing accuracy (resolution)
The lens performance data in this manual is plotted
for a sensing range of from 75 to 300 mm
(approximately 3" to 12"). For data concerning shorter
or longer sensing distances, or for general help with
lens selection, contact Banner’s factory applications
engineers at the address or numbers listed on the
back cover.
Field of View
Field of view is the area captured within the pixel array.
Because the array is rectangular in shape at 512 x 384
pixels, vertical and horizontal field of view values are
not equal.
The vertical field of view is the smaller value, and is
parallel to a line drawn down the sensor length from
top to bottom, through the center of the lens.
The horizontal field of view is the larger value, and is
parallel to a line drawn across the sensor width
through the center of the lens, and at right angles to
the vertical field of view.
To increase the field of view, increase the lens-to-
object distance or use a lens with a shorter focal
length.
To reduce the field of view, decrease the lens-to-object
distance or use a lens with a longer focal length.
The graphs on page 26 plot the effect of lens-to-object
distance on field of view for three lens choices.
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