But sometimes this simple logic isn't correct, like here the example of family pictures made with a SLR.
And sometimes you can't recognize what the first photographer wanted to show like in the following pictures..perhaps windows???
The first phtographer used a Minox 35 GT with a Kodak Farbwelt 200 film.
For the double exposures I used the spacy Yashica 108 MP with a Sigma MC 3.5-4.5/35-135mm lens and photographed my girlfriend, who posed with a Zeiss Ikon Contaflex IV.