I realize this is an old thread and a subject that's been discussed a lot, but something I can't seem to figure out with regard to a pre-asph Summilux hood is that neither a 12504 or 12524 comes anywhere close to fitting my summilux (SN 239xxxx), or at least the particular samples of those hoods I have. And I don't think it's just a matter of worn retaining clips, since there seems to be a gap of a full ~1mm on every side of the lens with these hoods, and like I said, are nowhere close to fitting.
Was there a change to the physical size of the front of the Summilux at some point in its development? I know there was apparently an optical formula change at some point in the ~21-22xxxxx range of serial numbers, but I've never seen reference to a physical change in the lens.
I see references here to a 42mm diameter lens front. I measure mine at 39mm (maybe 40). And that's the exterior, not interior of course. Does anyone else have this experience? And any ideas for a hood in this case?