Appendix A Creating a Good Image
A-16 Visionscape FrontRunner™ User’s Manual v4.1.3, April 2012
Depth of Field
Depth of field is the size of the front-to-back distance that is in focus. The
aperture opening is the most important influence in determining the depth
of field:
• When using a small aperture (high f-stop number), much of the area,
both in the foreground and background of the object, will be in focus.
More light is required when the aperture is small. This provides
greater depth of field and reduces the effects of ambient light.
• When using a large aperture, the object is in focus, but the areas in
the foreground and background of the object are out of focus.
• Many lenses come with an information sheet detailing depth of field at
various f-stop settings and working distances.
Lighting Tips
• To light a round part, try using a round light source that provides even
lighting on the inspected parts, such as CDI (Cloudy Day
Illumination).
• Experiment with different light positions and sources until you find the
best illumination for your part.
• If you place a point-source light close to the part, you will likely
produce a harsh glare with black shadows.
• To fill in (minimize) shadows, use lighting sources with a diffuser such
as CDI.
• Your lighting should be much brighter than the room in which the
inspection is taking place.
• It is often best to light the environment, not the part.
• An enclosure around the inspection station will minimize the impact of
ambient light as well as protect lights and cameras.
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