I was reviewing some S16 I recently shot and transferred, and in a few scenes I noticed what I originally thought was lens flare. However, the more I look at the transfer and compare the scenes in question back to back, I'm thinking it was more than likely a small spot or speck of dust on my filter or lens. I was filming with my SR3, Canon 11.5 - 138 zoom with a clamp-on Chrosziel 4x4 sunshade, and a 4x4 Tiffen 85 filter.
I've uploaded a short clip with a few scenes in which the small spots are visible, so if anyone can take a look and let me know what you think might be the culprit, I'd appreciate it. The spots are horizontally toward the center of the frame and vertically about a third of the way down from the top of the frame. I'm pretty sure I checked the filter and lens for dust or dirt before and after I was filming that day, but I certainly could have missed something. Since the spots are in approximately the same area in scenes filmed at 11.5mm with the 85 filter in and don't appear to change as the camera is panning, I'm thinking this was likely an issue with the filter.