Cloning Problem ... PLEASE HELP!
Posted: Thu, 15th Feb 2007, 3:24am
Post 1 of 12
I'm new to Visionlab. Just learning how to do things. Anyway I wanted to make a clone of myself standing next to me. I put one video over the other and masked out half of the top video so it looked like I was standing next to me. I ran into a problem though.... some how one video is lighter than the other one all of a sudden. So you can see where the two videos are joined. Why is this happening? What can I do to correct this problem?
Posted: Thu, 15th Feb 2007, 3:34am
Post 2 of 12
Hey, welcome to the community.
The reason this has happened is because your camera has auto-focus on, and must have closed the shutter a little bit to let in more light because of a change in the lighting situation.
There are multiple things you can do, the easiest one to do is when filming, make sure after your camera has auto-adjusted to the current light & focus settings to switch it to manual focus mode so that the focus won't change.
Or, alternatively, you could attempt grading the footage to look the same by decreasing the brightness a small amount.
Posted: Thu, 15th Feb 2007, 3:39am
Post 3 of 12
Having absolute control of the lighting is beneficial for split-screen compositing. Did you film your clips inside or outside? Even the subtles shift in the sunlight becomes painfully obvious when you slice the frame down the middle. Here's some tips that may be helpful, aside from using manual exposure, which was already mentioned. I assume that it is just along the seam that you have a problem. If one entire side is way too bright, click the name of the clip on the timeline and make sure the composite mode is set to Normal.
If possible, artificially light the scene, so you have total control. Typically a cloudy day has consistant enought light to pull this effect off as well. Avoid direct sunight at all costs, as even the shifting of shadows between the times you get the shots can cause problems.
Avoid backgrounds containing any moving objects. The slightest breeze in a tree behind your actor will show your seams.
When splitting the screen, try to follow hard lines in the background, if there are any, as a subtle change from one side to the other will be less obvious. Putting something like a doorframe in the background can give you a clean straight line to follow and make the effect easier. Another technique is to feather the edge of the mask, so the two sides blend together. Usually proves tricky and difficult, but sometimes it works.
Posted: Thu, 15th Feb 2007, 4:12am
Post 4 of 12
I'm not so sure that it's my camera. I filmed it inside my house. I basically just imported one video into Visionlab, I split that video on the time line to get both videos. When I filmed the video I basically just kept the camera rolling while I sitched to the other side of the scene. If I remember correctly I think the top video lightened up when I applied the mask in Visionlab. I'll have to play around with it some more when I get home from work.
Posted: Thu, 15th Feb 2007, 4:28am
Post 5 of 12
did you apply a mask to it on both sides... its been a while since i did any cloning work, but i'm pretty sure thats what you have to do. To get 'em to match, copy and paste the first one, then hit the invert button...
if that doesn't fix it, you'll have to get into some grading...
Posted: Thu, 15th Feb 2007, 4:35am
Post 6 of 12
Thanks for the help guys. I'll have to play around with it some more to see if I can get both videos the same. This is my first time asking for help in the Forum. Had no idea people would be so helpful and respond so quickly.
Posted: Thu, 15th Feb 2007, 5:59am
Post 7 of 12
That is a very impressive thing about this forum. The community support you get is amazing. If you could post an image or a quick clip so we could see it, I'm sure somebody could quickly figure out exactly what is going on, and help you get it sorted. Not sure if you have anywhere to host such things, but www.imageshack.com
works for pictures, though I've never used it personally.
Posted: Thu, 15th Feb 2007, 7:01am
Post 8 of 12
Something I've discovered in working with this type of thing: standing in different areas cause light to spill over you differently. Reflections and shadows can change drastically (well, drastic when you're trying to do what it is you're doing) depending on your relative distance and position to the primary source of light in the room.
Thus, like it was said before, take complete control of your lighting.
Posted: Thu, 15th Feb 2007, 9:18am
Post 9 of 12
This definitely sounds like a camera issue. You should be able to fix it using the grading filters to re-balance the brightness in the shots. As Axeman says, feather the mask to make the seam less obvious.
As others have said, when doing cloning shots it's vital to have full manual control over your camera as well as your lighting.
Masking the shot shouldn't have made any difference to its brightness unless you altered something else at the same time.
Posted: Thu, 15th Feb 2007, 2:26pm
Post 10 of 12
I ran into this issue once before and had to correct it with grading. My scene was also filmed indoors using one continuous shot that I split in post. While I had locked my camera down with manual focus, I left the white balance on auto. That hosed me up and I had to correct it using A LOT of subtle keyframed brightness changes. CLab handled it brilliantly, but I could have saved myself a lot of time by verifying that my white balance was manually set. This is something else that you may want to verify on your camera.
Posted: Sun, 18th Feb 2007, 5:31pm
Post 11 of 12
What I would recommend for cloning is using a greenscreen, so then you don't have to have your camera holded in place. It just saves you time of cutting the video in the exact right place.
Also, by using a greenscreen, it's OK if one video is a bit brighter than the other, since it's only the actual person who's going to look different.
Posted: Sun, 18th Feb 2007, 9:31pm
Post 12 of 12
However, greenscreens lack shadow, light spill, and reflection of objects in the background. They also take a lot more time and effort than split-screen cloning and still don't look as great.