mvBlueGEMINI Technical Manual (EN) v2.6
APPENDIX 36
Because single lenses have strong aberrations, several lenses are used to compensate these
errors.
The wavelength of the light has a great influence on the image. For each wavelength, the image
quality is good and/or is sharp in different spots.
By the use of the mentioned corrections with several lenses, it is tried to consolidate these levels.
An achromatic lens, for example. is a lens with two corrected colors. Other wavelengths vary
from it a bit.
An apochromatic lens is a lens which is optimized for three wavelengths.
Figure 5 Lens correction
Zoom lenses often consist of 10 or more lenses.
Real lenses have an entrance pupil and an exit pupil. The parameters b and g are calculated
starting from these levels. If the distance of the levels equals h (also called main level), the total
setting distance e is between object and image.
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