New answers tagged optics
If you need to retain infinity focusing capability, one solution might be using lenses with longer focal length, like 135mm or longer. At least some will have the rear element far away from the sensor plane. It does not even have to be native Canon lens, Canon bodies can adapt lenses from other brands, like Nikon, Zeiss etc. - with appropriate adapter.
You could use extension tubes, that add directly their length to the focal distance or you can buy macro negative lenses and you can mount them on the front lens. Also inverting the lens could be a solution, but is less used because you lose AF and aperture.
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