Originally posted by UncleVanya That doesn't really clarify why it is so much bigger and heavier than the competing lenses for other systems to me. Unless it is due to IBIS vs. OIS
Actually both approaches needs a larger image circle then a non stabilized system. IBIS because the image sensor moves within a larger stationary (with reference to the camera body) image circle. OIS because the image circle moves on the stationary sensor.
I don’t think the stabilisation group (glass, coils, springs) has to be notably larger or heavier then a stationary group, so in theory OIS shouldn't add much weight compared to IBIS. I don’t know the reason for the D-FA* 70-200 are heavier then the competition, but I suspect its due to extremely high optical quality. Something that should make this lens last (in sale) for at least a decade, even if we get 100 Mp FF sensors by then. If this is as I suspect, its similar to how Sigma have been thinking lately. Quality before lightweight.