night shots

[pingupingu]

taking night shot with g3 (without any filter ) at 8 or 15 second and f8 or more i have star filter effect on streets lamps.

i had not that with my old eos50 and standard zoom.

how can i avoid that ? ( by another opening ?) or a filter ?

thank you.

[drisley]

Yes, if you open the aperture, you will reduce the star effect.
Usually f3.5-f4 work best. If you go much wider (f2-f3), you risk getting chromatic abberation (blue fringing around bright lights).