Long exposure bridge. Reflection?

[_t_is_me_]

I took my camera downtown the other night to take some photos for the class I'm taking. I ended up getting a few that I really like, but one of my favorites (and some others) have this weird reflection. It's upside down and flipped, and very noticeable. I'm wondering if anyone can tell me why this happened and/or how to prevent it in the future? My guess is that it has something to do with the fact that I didn't cover the viewfinder, but I can't really wrap my brain around that.

 

[KmH]

What make/model camera do you use?
Where in the photo you posted is the reflection?

If you used a DSLR the camera's main mirror is up against the bottom of the viewfinder during an exposure and blocks most of the light from the viewfinder.
In other words what little bit of light that can enter the viewfinder could not be in focus in the photo so you could tell it was upside down and flipped.
Consequently it's likely lens flare, and because of the way lenses work lens flare is usually upside down and flipped.
In fact, the scene the lens projects onto the camera's image sensor is upside down and flipped.

Lens flare is reflection(s) inside the lens at air gaps between lens elements. Bright lights in a scene usually cause the reflections in a lens.
Adding a filter to the front of the lens, like a UV or clear filter for 'protection', adds an air gap between the filter and the front lens element. Cheap filters usually lack filter coatings that help to minimize flare.

 

[_t_is_me_]

What make/model camera do you use?
Where in the photo you posted is the reflection?

I have a Nikon D3200 DSLR. The reflection is pretty much centered in the photo, above the bridge (in the sky). I think you're right about the lens flare. I have a UV filter, so I will definitely try that next time. Thank you!