Not your typical "Frame vs Normal" thread, but SOMEWHAT related... at DVinfo.net

Ryan Thomas · March 25th, 2007, 06:39 PM

Ok, is the Frame mode actually considered progressive or not? Can anyone explain?

Also, one other question. I film a lot of fast motorcylce racing. Can anyone explain why in Frame mode on Auto, I never get any kind of a blur, but if I use TV or sny other Manual mode and set a high shutter, it blurs when the bikes go by?Thanks.

Ryan

Dale Guthormsen · March 25th, 2007, 10:04 PM

Ryan,

If you want the video to blur use manual or TV use about 1/60 or 1/100 and you will get plenty of blur. You could go as slow as 1/30 and in that speed even a walking person can show movement blur. You could also use nd and a polarizer which will open up the aperature a couple few stops and that would reduce depth of field giving you more blur to your footage. I shoot in Frame (progressive, so to speak) all the time in 16:9 and have no issue with this.

Jim Andrada · March 25th, 2007, 10:54 PM

I think the original question wan't so much about wanting (or not wanting) blur as about why there was more or less blur depending on camera settings.

I'm really interested in this as well, and I haven't yet seen this effect so shouldn't really comment, but I thought I'd go ahead and expose my ignorance in hopes of being corrected by constructive criticism.

As I understand it, the GL-2 frame mode is a "sort of" approximated progressive mode. It's not interlaced, but perhaps also not true progressive. I think they take the two fields and somehow "interpolate" them to get a "blended" image instead of just interleaving them.

Re the blurriness, I think (not sure - somebody who really knows please feel frr to tell me I'm wrong!) the net of it is that each Frame mode frame might be a bit softer than an interleaved frame, but also smoother because there wouldn't be any jaggies where two fields taken 1/60 of a second apart didn't quite line up on a fast moving object.

So this speaks to the blurriness of the composite image - ie the image built up from two fields.

Each field would also be more or less blurry depending on shutter speed. The slower the shutter speed, the fuzzier each field would be for a fast moving object. Faster shutter speed would produce crisper fields, but the fields making up a single frame would have been taken further apart in time, so the image might appear more "jittery".

So the shutter speed trade off would appear to be between smoothness and jitter, and the frame mode trade off would appear (to me anyhow) to be between smoothness and jaggedness.

There's also the fact that higer shutter speed implies larger aperture which might lead to more softness due to shallow depth of field

How all of these would interact really gives me a headache to think about.

I think if it were me, I'd try to separate the effects as much as possible in a series of separate experiments, and then see which I liked best, and go with it.

March 25th, 2007, 06:39 PM	#1
Ryan Thomas Regular Crew Join Date: Dec 2006 Location: Conroe, TX Posts: 37	Not your typical "Frame vs Normal" thread, but SOMEWHAT related... Ok, is the Frame mode actually considered progressive or not? Can anyone explain? Also, one other question. I film a lot of fast motorcylce racing. Can anyone explain why in Frame mode on Auto, I never get any kind of a blur, but if I use TV or sny other Manual mode and set a high shutter, it blurs when the bikes go by?Thanks. Ryan

March 25th, 2007, 10:04 PM	#2
Dale Guthormsen Inner Circle Join Date: Jun 2005 Location: Saskatchewan Posts: 3,048	Ryan, If you want the video to blur use manual or TV use about 1/60 or 1/100 and you will get plenty of blur. You could go as slow as 1/30 and in that speed even a walking person can show movement blur. You could also use nd and a polarizer which will open up the aperature a couple few stops and that would reduce depth of field giving you more blur to your footage. I shoot in Frame (progressive, so to speak) all the time in 16:9 and have no issue with this. __________________ DATS ALL FOLKS Dale W. Guthormsen

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March 25th, 2007, 10:54 PM	#3
Jim Andrada Inner Circle Join Date: Feb 2007 Location: Tucson AZ Posts: 2,211	I think the original question wan't so much about wanting (or not wanting) blur as about why there was more or less blur depending on camera settings. I'm really interested in this as well, and I haven't yet seen this effect so shouldn't really comment, but I thought I'd go ahead and expose my ignorance in hopes of being corrected by constructive criticism. As I understand it, the GL-2 frame mode is a "sort of" approximated progressive mode. It's not interlaced, but perhaps also not true progressive. I think they take the two fields and somehow "interpolate" them to get a "blended" image instead of just interleaving them. Re the blurriness, I think (not sure - somebody who really knows please feel frr to tell me I'm wrong!) the net of it is that each Frame mode frame might be a bit softer than an interleaved frame, but also smoother because there wouldn't be any jaggies where two fields taken 1/60 of a second apart didn't quite line up on a fast moving object. So this speaks to the blurriness of the composite image - ie the image built up from two fields. Each field would also be more or less blurry depending on shutter speed. The slower the shutter speed, the fuzzier each field would be for a fast moving object. Faster shutter speed would produce crisper fields, but the fields making up a single frame would have been taken further apart in time, so the image might appear more "jittery". So the shutter speed trade off would appear to be between smoothness and jitter, and the frame mode trade off would appear (to me anyhow) to be between smoothness and jaggedness. There's also the fact that higer shutter speed implies larger aperture which might lead to more softness due to shallow depth of field How all of these would interact really gives me a headache to think about. I think if it were me, I'd try to separate the effects as much as possible in a series of separate experiments, and then see which I liked best, and go with it.