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-   -   GL2 / XM2 Frame mode (https://www.dvinfo.net/forum/canon-gl-series-dv-camcorders/3415-gl2-xm2-frame-mode.html)

Tatsuya Graham December 31st, 2007 07:27 AM

Hey, I shoot in 30p (frame mode) and im also thinking about switching to 60i and then transfering to editing program to deinterlace.. I have built a 35mm dof machine and it works great. If you need any help on building one, I will be glad to help you!


I have some 35mm videos on there.

Cole McDonald December 31st, 2007 12:17 PM

Keep in mind that when shooting in 60i and converting later, the timeslice is different and you won't have a "real" reproduction of any motion in the frame. With 24fps and 1/48th shutter, you are catching one-half of every 1/24th of a second (hence the strobing/judder on fast motion in the frame). At 60i with a 1/60 shutter, you are catching 100% of the motion and the software is trying (I emphasize trying) to replicate the motion characteristics that it would normally get from the smearing of the subject from point a to point b over a given timeslice.

As it does this it's trying to rectify the disparate timeslices that make up this moment in time from shorter, incomplete frames (interlaced is...um...interlaced). You will never get true motion from interpolation, although you my get close, but since the goal is to make it look like 24p according to all of these "film look" threads, the interpolation of motion here is what breaks the image when converting.

Don't test your footage on still images, you will always get the same result...footage shot in 60i is phenomenal as the interpolation doesn't have to do any actual work, it just mushes together the fields and calls it good. Rather test people running across the frame, the camera panning with them running (look at what happens to the background), camera pans (if you're slow enough, it'll look alright...any faster and the fields will separate so heavily that you'll have the software throwing away 50% of the resolution over the whole image anyway. Since the goal is replicating the motion of 24p, test the motion of the conversion. Otherwise, your beautiful tests of the conversion will leave you scratching your head when your car chase turns to mush after conversion.

Best case, shoot your talking heads and ping pong dialog in 60i and shoot motion shots in 30p/24p. More importantly, throw more light on the scene to get the exposure up higher as shooting 24p - 1/48 shutter pulls in half the light that shooting 60i - 1/60 shutter does. Your graininess should go away as you reintroduce the light you're taking away by capturing 50% of the time rather than 100% (the 50% is what you wanted though - hence the conversion).

Gian Pietri February 1st, 2008 05:03 PM

Thanks for the info guys, hopefully I can shoot some footage in the comming weeks. Unfortunately my next few Saturdays will be spent (drinking) at Universal Orlando's Mardi Gras, and Sundays recovering from Saturday night. I guess I can shoot some hung over footage of my friends and I and see about converting to 24p. I have a friend helping me build a 35mm dof machine. Thanks for offering to help Tatsuya, I'll post on my progress if any.

Travis Halverson April 22nd, 2008 10:55 PM

how well does frame mode footage match regular interlaced GL2 footage? I am thinking about shooting some stuff that will be played back in slow motion with some stuff that has already been recorded in the normal setting.

Barry Goyette December 22nd, 2008 09:11 AM

There is a slightly different motion signature between the two approaches. The frame mode does look like film to some people, where as the typical interlaced is what we've seen in video production forever. For you, the primary question will be your delivery method. If you are shooting for Web based distribution, its better that you shoot in frame mode, as computers use progressive scan, which is essentially the same as Frame mode. Shooting in frame mode will eliminate the interlace scan lines that you occasionally see in some films on the web.

If you are shooting for DVD, it really doesn't matter. There will be a slightly less "smooth" quality to the frame mode, and I suppose if things are really moving fast in a close-up kinda way, then standard interlaced mode might be "slightly" better. It depends more on the look you want.


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