I used my kit lens .... as that's the widest I had at the time ... and blow me down ... it turned out pretty damn good.
I had mine out to 18mm ... on the tripod ... bulb mode ... f/8. And just shoot.
I was amazed how simple it was ... oh ... turn off NR (it takes the same length black frame immediately after).
My remote shutter allowed me to used Bulb mode ... this made life easier.
Photobucket is blocked here at work ... but here's the link from my OLD post.
http://www.pentaxforums.com/forums/p...fireworks.html