Question on Zeiss 1.8/24 ZA on star effect

I just purchased this lens and paired it with my NEX-5N. Coming from Biogon user, I thought this ZA lens will produce the same star effect if we shoot directly into light source/lamp, but it did not.

Does any one knows why? Is it because of the retrofocus/distagon type of lens formula? or is it the coating?
It would be nice to have that star effect I just saying is all.

Below is the 2 shots I took last night using the ZA, compared it Biogon on third picture.

with E 1.8/24 ZA lens

With Biogon 2/35 ZM lens

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-=SJRM=-

In this ever changing world, to freeze it in time is a joy.