4.4 Lenses
Fairchild Imaging does not supply lenses; contact your local optics supplier for available lens models.
4.5 Illumination
The amount and wavelengths of light required to capture useful images depend on the particular application. Factors include the nature, speed, and spectral characteristics of objects being imaged, exposure times, light source characteristics, environmental and acquisition system specifics.
It is often more important to consider exposure than illumination. The total amount of energy (which is related to the total number of photons reaching the sensor) is more important than the rate at which it arrives. For example 5 ∝J/cm2 can be achieved by exposing 5 mW/cm2 for 1 mS just the same as exposing an intensity of W/cm2 for 1∝s.
4.6 Light Sources
Keep these guidelines in mind when setting up your light source.
•Halogen light sources generally provide very little blue relative to IR.
•
Some light sources age; over their lifespan they produce less light. This aging may not be uniform – a light source may produce progressively less light in some areas of the spectrum but not others.
Fairchild Imaging • CAM/CCD 2KCL.TDI &