Can't let go of that aging 35mm SLR accustomed to a strict film-only diet? Nikon seems to be toying with the idea of feeding its older models digits instead, judging by a Japanese patent application published last week. It was filed just last year and shows a digital back designed to be swapped out easily, complete with a screw adjustment to fine-tune the all-important focal distance. The patent was scoped by prolific Japanese blogger Egami, who pointed out that a different design would be required for each of Nikon's film SLR models, which all have different backs -- but an actual product coming to market seems quite a stretch anyway, at this point. Such devices are commonplace on medium format cameras though, and Leica even offered one for its R8 and R9 35mm SLR cameras as recently as 2007. Still, a pure digital version of our classic F2? Yes please.