In 1949 the Parvo 250 replaced the Leitz VIIIs. It had a new design (made by an artist) and a new elegant elliptically-shaped lamp house. The black Parvo 250 was changed in 1950 to Prado 250. The Prado 250 (it was the 1950 renamed Parvo 250) had a triple-walled lamp house, lenses of focal length from 85 to 150 mm, and different attachments for micro-projection or with a micro-aquarium. 

In 1953 the colour changed to grey. 1954 the stubby base was replaced by the elegant base. 

Lamp: cine socket bulb of 250 Watts, In 1954 the more powerful Prado 500 was introduced, a built-in blower in the base supplied the cooling and now lenses up to 250 mm were offered. Longer focal lengths were available on request.

For lenses of 200 mm or more a special long base was offered. 

For all Prado (250/ 500) a magazine changer was supplied. Leitz offered the Prado 500 until 1968, then the Prado Universal replaced it. 

By changing the condenser lens and the attachment and the lens it could be changed to a Prado 66 for 6x6 cm slides. In 1960 or 1961 the colour changed to light blue.