FORUMS: list search recent posts

Circular lines appear in video on 7D .

COW Forums : DSLR Video

<< PREVIOUS   •   VIEW ALL   •   PRINT   •   NEXT >>
Kadshah Nagibe
Circular lines appear in video on 7D .
on Aug 6, 2011 at 1:41:15 am

I noticed some circular lines in my 7D footage. I went out and did some test and found out its not the ND fader which at first I thought was the problem or the lens. To figure out the problem I filmed without any filters and I swap out the canon 17-55mm for the Tokina 11-16mm lens and I still see the same horrible lines in my footage. I also noticed the the lines are not all circular but various in shape and are more noticeable in the bright sky and when the camera is panning. I looked at old footage I shot last year and the same lines are in all my footage, don't know how I didn't notice it before.
I was always able to get around moire and aliasing but this is too much. A friend of mine said it may be H264 compression. Does anyone have a clue of what this is? Here are a few samples.
http://www.sweetproductionmedia.com/weird%20lines.jpg
http://www.sweetproductionmedia.com/weird%20lines2.jpg
http://www.sweetproductionmedia.com/weird%20lines3.jpg

-kaj

http://sweetproductionmedia.com


Return to posts index

Peter Burger
Re: Circular lines appear in video on 7D .
on Aug 6, 2011 at 8:05:07 am

Yes, it's a mixture of "banding" (the lack of 8-Bit video to create smooth transitions) and the very heavy H.264 compression.

This problem was discussed in a recent thread, that you might want to check out:

http://forums.creativecow.net/readpost/280/6755

------------------------------------------
"Tragedy is a close-up; comedy, a long shot." - Buster Keaton


Return to posts index

Kadshah Nagibe
Re: Circular lines appear in video on 7D .
on Aug 6, 2011 at 6:35:09 pm

thanks this is very helpful. I think the banding is introduced in the original 7D footage and not post since I'm able to see it in my monitor. In this situation is there anyway to fix it? Would using a different picture profile such as neutral make it less noticeable?

-kaj

http://sweetproductionmedia.com


Return to posts index


Peter Burger
Re: Circular lines appear in video on 7D .
on Aug 11, 2011 at 12:04:54 pm

Sorry, for the late answer, had no internet the last couple of days. Shooting neutral might help a bit (I use neutral, faithful or the Technicolor Cinestyle most of the time) but what's even more important IMHO is to reduce sharpening (set it to zero and do sharpening in post) and contrast (also recommended to set it to zero), this is what introduces all kinds of artifacts to your footage and the very heavy H.264 compression boosts them.

hth

------------------------------------------
"Tragedy is a close-up; comedy, a long shot." - Buster Keaton


Return to posts index

Kadshah Nagibe
Re: Circular lines appear in video on 7D .
on Aug 11, 2011 at 4:19:48 pm

I use the Cinestyle picture profile and I have both contrast and sharpening set to 0. Once you notice the banding you can never get it out of your mind.

-kaj

http://sweetproductionmedia.com


Return to posts index

Peter Burger
Re: Circular lines appear in video on 7D .
on Aug 11, 2011 at 9:13:45 pm

[Kadshah Nagibe] "Once you notice the banding you can never get it out of your mind."

Yeah, that's right... Banding occurs with gradients, so it's very hard to avoid... What I learned while working with HDV (that also uses heavy compression) is to keep the camera in slight constant motion, so compression doesn't "kick in" too heavy in plain (or almost plain) areas.

With my T2i and Magic Lantern I also can increase the bitrate. Unfortunately Magic Lantern is not available for the 7D...

------------------------------------------
"Tragedy is a close-up; comedy, a long shot." - Buster Keaton


Return to posts index


Kadshah Nagibe
Re: Circular lines appear in video on 7D .
on Aug 12, 2011 at 4:09:03 am

i thought it would be the other way around keep the camera lock down on a tripod and it wouldn't be as noticeable. ok thanks i'll do both and see what happens.

-kaj

http://sweetproductionmedia.com


Return to posts index

<< PREVIOUS   •   VIEW ALL   •   PRINT   •   NEXT >>
© 2017 CreativeCOW.net All Rights Reserved
[TOP]