There was an option on the Polaroid 600 model that doesn’t have autofocus to have a ‘Close Up’ lens built in. This feature was on the Sun/Spirit as well the OneStep 600 (not the box style Polaroids). You will recognize the cameras by the small plastic slider below and to the side of the main lens, between the lens and bright/dark compensation slider.
Moving the lever towards the lens slides a plastic lens over the front of the main lens as well inside of the viewfinder area. These are not precision ground glass lenses, so the lens and distance between the main lens and the close up lens can vary a bit between cameras.
Since this is a lens over a lens, you aren’t taking a camera that focuses 4 feet to infinity and giving it 2 feet to 4 feet range. There is a sweet spot, or distance, that each camera has. Normally, as I move from one 600 OneStep to the next, I find it difficult to get the exact ‘in focus’ distance when using the close up lens. So, I end up with things at different distances in and out of focus.
Using that ‘issue’ to your advantage, there is a first test you should do when you pick up a Polaroid with a close up lens before going out and using the camera. Place the camera in a spot on a long table or on the floor. Now, take small objects (chess pieces, small stuff animals, dominos… etc…) and place on at foot distances away from the camera. Be sure one does not completely hide the one behind it. If you are using things like chess pieces or dominos, you can place one every half foot to get more precision. Now, snap a photo. The print will show you quickly what the perfect ‘in focus’ distance is for that camera.