>>3195737Nikon has some appeal because there are lots of old film lenses out there for cheap. However, there are often compatibility issues using them in modern digital cameras (eg, older autofocus lenses won’t AF on low end DSLRs; meter turns off entirely on low end bodies when used with a manual focus lens; newer G lenses won’t let you change aperture on the older film bodies; etc).
With Canon, you have the advantage that any EF lens will work with 100% comparability on any EOS body, but that legacy only goes back to the mid 80s, so you don’t have the wealth of old manual focus glass Nikon has.
Pentax has compatibility going back to the 70s, but they’ve also always been a bit of a second-tier brand, so while your 1979s Pentax lenses will work fine on a modern K1, there aren’t really that many lenses around compared to the big two.
Another option is to, when you’re ready to move to digital, get a mirrorless Camera instead of a DSLR. Those can use any SLR lens with an adapter, often better than it works on the brand’s own modern DSLRs. So with that route, whether you shoot film on Nikon, Canon EF, Canon FD, Minolta, Leica R, Pentax, or whatever, you’ll still be able to bring your glass with you to digital land.
