Sure there is a better way. For s3D you should use controllers like the ste-fra lance, to start the cameras synchron and check it they stay in sync.

I don't have a lanc connector.

DonaldT: audio and video are always synced perfectly, i use audio peaks for 3D syncing, because its a lot faster.

Set your project properties to 50p. Then you can align on what was a field.

Have you tried it?

"It doesn't matter if i set project properties to 50hz, pairing can only do with 25hz accuracy"

I have viewed 50i as 50p many times, especially when I wanted to examine each field one at a time. I can't see why it won't do what I suggested. To view one field at a time. you have to set the preview to full/best.

Give it a try.

I just tried it a moment ago, and was able to slip the video forward 1/50 sec (= 1 new frame = old field).

Yes, this work, but try to pair it for 3D and you will loose this accuracy.
I tested.

Ordered two 50p cams :)

Why?

By setting the project properties to 50p it is the same as if you started with 50p sources, except that the vertical sharpness won't be quite as good.

Not exactly.
As i said, try it.
After pairing, vegas wont handle it as 50p footage.

Well, I am not into 3D and don't have any pairs of video, but I just put two independent clips on the timeline, one below the other, and I was able to slide each clip independently to any new frame position (both odd and even number of new frames). What am I missing? I was using Vegas 13. Do you have auto-ripple edit off?

@PeterDuke
Did you do it in a 3D project? I think that is what the OP is referring to, it works in a 2D 50p project but apparently not in a 3D project.

pair it, and examine left/right, switch many times, and you will not see those two frames what you paired at 50hz accuracy. Vegas know its a 25fps footage, and cannot pair left file top field with right file bottom field.

Right. I did not use nor ever have used a 3D project. If there is a difference in this regard then it is my ignorance.

That then leaves you the option of rendering out to a 50p intermediate, as you suggested in your first post.

Would nested projects work?

Well I have a lot of experience with s3D, and what goes wrong here seems to be not the point that the alignments of L and R does not work in Vegas - that works and is fine. The major issue is that the cameras wer not in sync during capturing the footage. To be in syn means that both cameras has to start recording at the same time, the readout of the sensors must run equally, and have to stay in syncronisation. Requirements are high here for s3D - you should be better the 1/1000s, and that can be done either with consumer units and lanc controlers or by using genlock. If the footage has been out of sync during the shooting, especially for fast moving motives it will not be possible to correct that in the post.

@relaxvideo
Out of curiosity, did you change the timeline ruler to "frames"? If you leave it in SMPTE you won't see each frame and you can't align frame accurate in a 50p project.

Wolfgang:
yes, perfect syncronization when fast motion is present, is a must, of course. But now we don't talk about this. Have you worked with 2x interlaced footage? Try to pairing, and you only can render out as 25p accuracy, even when you can pair on the timeline at 50p accuracy.

Oldsmoke: i will try, thanks.

But your approach is wrong. You have only 25 frames per second if you shoot with 1080 50i. And not 50 frames per second. So why do you think that you can pair the footage with the accuracy of half-Frames? Then you have to shoot with 50p but not with 50i.

"So why do you think that you can pair the footage with the accuracy of half-Frames"

Because the "half-frames" (fields) should have been converted into full frames in a 50p project.

Vegas does that in 2D. If it doesn't do that in 3D then it is a bug.

Wolfgang:

"You have only 25 frames per sec"
No, i have 50 fields per sec :)

"why do you think that you can pair the footage with the accuracy of half-Frames"
Because i can, but first i have to render to 50p.

But now 2x Sony WX350's are coming to me :)

Vegas is not able to edit on the field base, but only on a frame base. That is typical for most NLEs. The solution would be only to shoot with the paired cameras in 1080 50p/60p directly.

I do not know if that is a bug at all. I never had the idea to shoot in 50i and ignore the requirement to sync the shooting. Because if I sync the two cameras then there is no need to switch to 50p - because then you can pair the two 50i streams in a 50i project without any issue.

Vegas makes very good 50p/60p from 50i/60i when you set deinterlace to interpolate.

Wolfgang: yes, but as i wrote my cams doesn't have lanc.
I do mainly slow, relaxing movies, so syncing wasn't critical, only at waterfalls, etc. But here in worst case, i can render out to 50p, import back, and sync will be a lot better.

I didn't think either it's a bug. I just ask if a solution is exist inside Vegas or not?

Thanks OldSmoke,

I forgot that later versions of Vegas require the project properties to have the deinterlace method set to "interpolate" when you convert 50i to 50p. With say Vegas 9, the deinterlace method setting is not relevant.