Have you ever tried to take a picture of a child while he plays something? He will turn around and look at the camera. Same story if you try to take pictures of people in the park. They have a special sixth sense.
What to do to
to catch people by surprise?
To do this, they came up with a wonderful nozzle The Super-Secret Spy Lens.


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Its secret in the mirror installed inside the nozzle. You seem to direct the lens away from the object, and the object is perfectly visible in the viewfinder;). Such is the periscope.
Read more about the nozzle
here . Video with an example in the same place.
And
here you can order for 58 mm lens this very nozzle.