Cem, that is a lovely photo you have there. Great colours and effect on the water. At ISO-12800 I guess you cannot complain about the banding.
I've been to Amsterdam, and that place is great for these type of shots too.
This image of mine was taken a long time ago in Thailand on a canal (khlong), in Bangkok. All I had at the time was a little old Sony T5 compact. The flash power wasn't that strong, unlike normal flash output, it was set at rear curtain sync.
I seemed to remember it got me some great abstract light trails of the traffic on the roads, and so I used it for taking this photo too.
These light reflections were kind of detached and on they're own in the canal, when the candles floated by 'em, I took the shot.
The candles are used in the Loi Khatong ceremony where the Thai people (kun thai), float candles down the canal while offering up a prayer.