Greetings, I've had those spots on my footage as well... Well, just a single spot to be honest, I haven't had that much spots on my footage. I noticed it when I was making a cloud time lapse long ago with a Canon EF-S 18-135mm lens at 135mm.
- Spot in center of square
- Spot at right corner 1E.jpg (179.55 KiB) Viewed 906 times
- Spot in center of square
- Spot at right corner 2 E.jpg (197.05 KiB) Viewed 906 times
It is said that it's dust or artifacts over the sensor, it might be dust or artifacts in, or over the lens as well, moisture over filters. It might have happened when changing lenses, exposing them to the enviroment. A few days passed, and when I was going to shoot another cloud time lapse, I wanted to make a test without cleaning the sensor, so I first cleaned my lens, checked the footage, and the spot was gone.
- No spot after cleaning
- No spot on right corner or elsewhere E.jpg (190.24 KiB) Viewed 906 times
I really can't tell if your lens is damaged. But I can tell you that working at high ASA with really long lenses, like that Samyang, you might notice artifacts, like the sensor grid pattern, and that horizontal line on the center of the footage. Both of these seen on the BMCC's, I can't tell if the glass quality have to do with it. Make sure it's real clean, without signs of moisture or wear. The last thing you can do is to send it back.