I might appreciate a smaller backup body and specialist lenses tailored to it while shaving off some of the total weight and investment (I'm in a poor financial shape now). I'm not using the Canon 24/1.4 much, so I'm a little apprehensive about having so much money tied up. It's a lens that has its uses for me though, so I would not want to lose the capability. To boot, I'm aware of the fact that the 24/1.4 L has severe coma problems - I've seen that aberration creep even well into the APS-C sensor of the Sony NEX-3 (that me & my astronomer pal have tried it on), let alone the 1D4 sensor, even slightly stopped down. Thus a lens with better coma correction (I know that not many f/1.4 lenses may )
P. S. To be fair, I do not appreciate the fact that whenever someone mentions an interest in µ4/3 and APS-C (to a lesser extent) lenses, someone else starts bringing up all that stuff about (supposed) equivalence, whatever it is, and criticizing that interest. It would be a bit like saying "why do you need that bulky junk" whenever sometimes expresses interest about FF gear. Some things matter for some people while meaning diddly squat to the other. I am not a fan of shallow DOF - actually it's a big problem for me whenever I stumble into this issue - while it obviously matters a lot to some. That in itself doesn't invalidate my point, nor my work (no, being into mega-shallow DOF doesn't make anyone an amateur by designation as has been implied by a person above).
P. P. S. BC - Surely the 10-18 has piqued my interest after you proved its worth on FF, but the 16(17)-35 is my go-to range - has been since time immemorial - and I only need a lens to slot below it (I'm not into the 24-xx zooms like most of the shooters around me). For about 6,5 years I've been using the Sigma 14mm f/2.8 but also contemplating all kinds of crazy ideas (mostly using APS-C ultrawide zooms as primes towards the middle of their range). In the end, I always decided that I'd be better off just keeping the Sigma because it's a pretty old lens - selling it wouldn't give me a lot of money, and definitely not enough to buy a modern APS-C ultrawide. Since I'm not using this lens very often either, just like the 24/1.4, I'm not pressed to upgrade it, but I also can't imagine living without something in the range unless I move to FF, where 16mm would be plenty. I know that 14/2.8 on FF is ridiculously wide - I tried that when I was using a borrowed 5D Mark II for a while (didn't like it), and there was not a whole lot of subjects that really demanded such wideness.
P. S. To be fair, I do not appreciate the fact that whenever someone mentions an interest in µ4/3 and APS-C (to a lesser extent) lenses, someone else starts bringing up all that stuff about (supposed) equivalence, whatever it is, and criticizing that interest. It would be a bit like saying "why do you need that bulky junk" whenever sometimes expresses interest about FF gear. Some things matter for some people while meaning diddly squat to the other. I am not a fan of shallow DOF - actually it's a big problem for me whenever I stumble into this issue - while it obviously matters a lot to some. That in itself doesn't invalidate my point, nor my work (no, being into mega-shallow DOF doesn't make anyone an amateur by designation as has been implied by a person above).
P. P. S. BC - Surely the 10-18 has piqued my interest after you proved its worth on FF, but the 16(17)-35 is my go-to range - has been since time immemorial - and I only need a lens to slot below it (I'm not into the 24-xx zooms like most of the shooters around me). For about 6,5 years I've been using the Sigma 14mm f/2.8 but also contemplating all kinds of crazy ideas (mostly using APS-C ultrawide zooms as primes towards the middle of their range). In the end, I always decided that I'd be better off just keeping the Sigma because it's a pretty old lens - selling it wouldn't give me a lot of money, and definitely not enough to buy a modern APS-C ultrawide. Since I'm not using this lens very often either, just like the 24/1.4, I'm not pressed to upgrade it, but I also can't imagine living without something in the range unless I move to FF, where 16mm would be plenty. I know that 14/2.8 on FF is ridiculously wide - I tried that when I was using a borrowed 5D Mark II for a while (didn't like it), and there was not a whole lot of subjects that really demanded such wideness.