Stutter vs motion blur, V1U vs HV20

CClub wrote on 6/21/2008, 5:20 PM

In the video below, I shot footage of a student simultaneously with a V1U and an HV20. In the (A) section, it is the V1U footage; the (B) section is the identical portion shot with the HV20. In looking at the student's hands, The V1U has more motion blur while the HV20's footage is more "stuttering." I believe they both had the same shutter speed setting at the time (1/24). It isn't incredibly noticeable via the YouTube upload, but when viewed in HD on a large screen, the difference is quite obvious. The C section is a clip with the HV20 which is a bit more stuttery than the V1U, while the D section is also the HV20 with action but is not stuttery at all. Obviously, given the price difference, I'm not expecting my hv20 to fully match my V1U, but it actually does pretty well with good lighting such as this example, but the stuttering thing I was hoping to match up better between the two cameras.

While not much of a camera techie, I think I understand some of the issues at hand (higher shutter speed = less motion blur/more stuttering, lower shutter speed = less stuttering but likely more motion blur.

My two questions: 1) Given that I have the footage already, is it possible to make the HV20 footage more like the V1U portion; i.e., less stuttering and more of the flowing motion blur that the (A) section has with the student's hands? Will any FX filters or plugins do this? Will Mercalli stabilization software help or is that a different beast all together? 2) Then for the future, is there an HV20 setting or a Vegas answer to this problem (I checked the hv20.com site and they're all over the place with the answers to this issue)?

Comments

farss wrote on 6/21/2008, 6:54 PM

You could try using the motion blur in Vegas.
You need to enable the View of the video buss track and then insert a MB envelope. Also check under I think project settings which type of motion blur, asymtric would possbly get you closest to how a slow shutter creates MB.

Unfortunately like a lot of other applications Vegas does MB the easy way by using whole frames which does not give you an optically correct result. I think AE uses real optical MB but that'd have to involve a lot of calcs and be a real render hog.

Now if it's only a small part of your video that's giving you grief there is a better way to simulate motion blur that's more natural but it takes a lot of work. Use one of the blur FXs. Copy the clip onto two tracks. Apply blur to the upper one, get the blur direction to match the direction of travel, apply enough to get rid of the stutter, ignore how much you're blurring the rest of the frame while doing this. Now use a Bezier to cutout just the part that you need to apply the MB to. Keyframe and adjust everything to taste. A lot of work for sure! You could try using this in conjunction with the MB envelope on the buss track.

Getting back to the cameras , the only thing as you've correctly noted that'll affect this is fps and shutter speed / angle. On some cameras it's kind of tricky to actually lock the shutter to a fixed speed. Simply setting a shutter speed in the menu is almost certainly not enough. You need to switch the camera into full manual and disable the shutter. Most camera make a valiant effort to avoid over exposure and if all they have left to prevent it is shutter speed then they'll increase shutter speed, well that seems to be the thinking of the designers.

Bob.