It uses a simple rotary shutter with meniscus lens, and does not have a viewfinder.
A negative meniscus lens has a steeper concave surface and will be thinner at the centre than at the periphery.
To obtain exactly zero optical power, a meniscus lens must have slightly unequal curvatures to account for the effect of the lens' thickness.
Double-meniscus anastigmats use widely separated positive and negative surfaces, generally thick meniscus lenses, to achieve a flat field.
Further refinement of the form replaces the two simple meniscus lenses with achromats for chromatic correction.
There are Maksutov variations that use the same principle but place the meniscus lens as a sub-aperture corrector near the focus of the objective.
The 1955 model came with a meniscus lens, later replaced with an achromatic lens.
In 1804 William Hyde Wollaston invented a positive meniscus lens for eyeglasses.
It consisting of a small meniscus lens and Mangin mirror as its "secondary mirror".
Like any simple meniscus lens, the Holga lens exhibits soft focus and chromatic aberration.