Those last three I took with my very simple, not very good, Sigma 70-300mm in the Macro Mode (between 200 and 300mm I can set it to "macro"), and a tiny (!) aperture. With the lens in "macro", DOF is narrow, anyway, so a tiny aperture a) helps to create the star bursts, but b) does not give me much of a depth of focus, so the background blurs out like this.