Imaging system for a projector with alterable focal length for use in stage or studio lighting

摘要

A picture system (30) comprises a first lens member (31) and a second lens member (32) which can be slid relative to one another. There is a combination of an iris aperture (33), an aperture slider set (35) and a gobo- slide-in compartment located between a condenser system and the second lens member in the radiation path. The second lens member has a refractive power that is greater than, or equal to, twice, yet smaller than, or equal to, three times the refractive power of the first lens member.