Spots on Timelapse footage

[Brian Shephard]

So...I was playing around with time-laspse this weekend, shooting some rolling clouds. When I got back to my computer and looked at the monitor, I saw several spots on the image. I was shooting interval recording, 1 frame every 4 or 8 seconds, 1 sec exposure.
I used a 1.5 IRND, as well as a TruPol Linear polarizer. Both filters and the lens are clean.

Can anyone tell me what these spots are from?

http://www.flickr.com/photos/79608538@N04/9862646544/
http://www.flickr.com/photos/79608538@N04/9862651245/

Here is a vimeo link so you can see them on motion (maybe a little easier to see all of them): https://vimeo.com/75114116

Thanks in advance.

 

[Federico Rizzo]

It seems you need to clean the olpf in front of sensor.

 

[Terry VerHaar]

They very much look like something on the lens or the filters. Water spots or problems with coating. Don't know what else they could be. Did you look at all surfaces? Both sides of filters and inner glass as well as outer glass of lens? Could even be inside the lens.

EDIT: Or, it could be the OLPF. :smiley:

 

[Marcos Montenegro]

What Federico said. Clean the olpf in front of sensor. No biggie.

 

[Brian Shephard]

Thanks guys. I appreciate the responses. I'm sure all of the filters and lens were clean (unless it's inside the glass). It probably is the OLPF. I didn't think about that. I've never cleaned it. Is there any special procedure or precautions in doing so?

Thanks!

 

[Brian Shephard]

I see that Red recommends using Sensor Swabs. Does anyone know which type (1, 2, or 3) is correct for the Epic? I don't see RED on any of their "which type to use on which camera" list.

 

[Russ Fill]

After shooting thousands of Timelaps these are most likely dirty OLPF dust or water spots, if you were stopped down anything above say 5.6 or 8. I would strongly suggest using a loop to make sure that the OLPL iis where you need to clean so you don't just keep grinding away at something thats not there. Also if you shoot a test really stopped down, at say a white pice of paper filling the frame youll probably see a lot more and have a better idea of what your up against before you start. just using a hand ball blower to try to blow some of the dust away you can start to see what is really there and what is moving around.

 

[Brian Shephard]

Thanks, Russ. I was able to see a couple of specs on the OLPF. I just used a little compressed air and that worked just fine.
FWIW - I did get the Sensor Swabs, just in case. RED recommended using the 16mm or 24mm sizes with Delkin fluid.

 

[ericyoung]

Have a look at the Arctic Butterfly brush and Sensor Loupe, and Giotto Rocket Blower, and Eclipse cleaning fluid too.

My preferred order of OLPF cleaning, only moving on if the previous step doesn't do the job) is:
Giotto Rocket Blower (never runs out, has a dust filter, no propellant to worry about getting on the optics)
Arctic Butterfly brush (antistatic, gentle - quite fiddly though)
Sensor Swabs with Eclipse fluid

 

[Flo Eckhardt]

I think it´s almost 100% water marks on the sensor .... you should definitely clean it. Use pfclean software to get rid of the spots if you need.