Circular lens flare indoors with a hood?

[pstake]

I just processed a roll of film, Tri-X @1600. All the photos were taken at night and/or indoors. The images in question were actually taken in a basement room with ordinary indoor lighting (incandescent?)

I was using my Kiev IIa with a Sonnar 50 1.5 and a vented lens hood. Three images taken from essentially the same place in the room, at either f1.5 or f2, all came out with a wide circular flare.

At least I hope that's what it is. I'm just a little confused because the hood should take care of the flare and especially indoors — or so I thought!

Anyone else ever had this happen?

 

[BMbikerider]

Lens coating and hoods can only do so much. If the light was in direct view of the lens then that is your answer. The Sonnar will have only primitive lens coating (if any) when compared to modern multicoated optics which even they will struggle with direct light.
The vented hood, I'm assuming you mean one that has sections cut out at the base, if the light source was getting though them theres another cause for your problem.