I find it easier to think in linear increments rather than logarithmic ones... As for feet/inches Vs metres: I don't know anyone who talks about a 0.050 metre lens - they use centimetres or millimetres: so now we have a THREE unit system...

I wouldn't dream of using anything other than metric SI units in my technical life, but for everyday use, feet/inches/yards/miles/etc are more intuitive and practical ( I might draw the line at perch, chain and hand, but it's nice to know they are there if I ever need them )...

Cheers, Bob.