400$ for 55-200 6.3 kit telephoto zoom?
Are they out of their minds?
because that 1/3 of a stop difference between 6.3 and 5.6 is going to make a huge difference in price.
That 1/3-stop means a 20% reduction in the size of the front element, so yes...that could make quite a significant difference in both lens size and cost. That's something Tamron, Sigma, etc., have done for years (although they then have to 'spoof' the AF system to show the lens as f/5.6).
size yes. cost? do you think an element that is 35mm versus one at 31mm is going to significant change the price?
all things being equal - tooling, zoom mechanism, making it this small, STM motor, IS, and the other 14 elements that are less aperture sensitive are going to more cost related.
17 elements in 11 groups - is quite sophisticated for it's intended market / price class.
the EF-S 55-250 STM has 15 elements in 12 groups
and as another example, the Sony E 55-210 is 13 elements 9 groups.
the sony rolls in at 63.8 x108mm as far as size for the same aperture range.