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Old December 17th, 2002, 09:37 PM   #1
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30 frame effect

does the 30 fps video effect (not frame mode) reduce resolution on the xl-1? I would rather use this to get a bit more light.
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Old December 17th, 2002, 10:07 PM   #2
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You know, some people say this is true, but I think that this is really exaggerated. It might be the case that some of the pixels on the CCD don't get used for some of the frames, but it's still a 720 x 480 picture and probably indistinguishable to the naked eye - unlike the 16x9 anamorphic stretch mode, which clearly does compromise significant resolution.
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Old December 18th, 2002, 08:03 AM   #3
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You are not loosing actual pixel resolution, but quality. The camera's
CCD chips & electronics aren't fast enough to actually scan 3
CCD's each frame. So what it does is some form of de-interlacing
with smoothing and such. So you loose quality and sharpness
here (which actually can be seen). Some people prefer it however.

Search (by using this forums search feature) on the words frame
mode and you will find plenty of threads on this subject. There
also was an article out there that explained it much better than
my words in clear pictures, but I don't seem to be able to find
the link to that article at the moment. Perhaps someone else
knows it.

Hope this explained it some
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Old December 18th, 2002, 11:21 AM   #4
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Well then the question is - is the internal frame mode better than using the video editing software to deinterlace the footage?
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Old December 18th, 2002, 12:28 PM   #5
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Actually, my question is whether the frame movie mode better than the 30fps digital effect
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Old December 18th, 2002, 01:39 PM   #6
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Ok now I don't know what you're talking about. Do you mean merely adjusting the exposure setting to 30fps for lower light situations? No that should not affect quality at all. You should have a normal interlaced 60i video that will simply not have as smooth motion as you would with a 1/60 shutter.
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Old December 18th, 2002, 03:11 PM   #7
 
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no matter how you slice it, the XL1s shoots in interlaced mode, ONLY. Normal mode is standard 60i with one field captured every 1/60 sec. Movie mode is interlaced with 2 fields captured simultaneaously every 1/30 sec.
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Old December 18th, 2002, 03:17 PM   #8
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Frame mode aside, you should have no problem shooting in 30fps in low light. The image will not be degraded. Probably look better than 60fps with gain up. There will be a tendancy for more motion blur but it shouldn't be noticeable unless there is alot of movement in the scene. Even then you might like the look.

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Old December 18th, 2002, 03:23 PM   #9
 
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Yes, I believe the question is whether the 1/30 digital shutter speed is better/worse/same than the frame mode.

Personally I use the 1/30 shutter and leave the frame mode off. You get a bit more motion blur (though not too much) with the 1/30 than the Frame Mode so it makes it seem a tiny bit smoother to me.
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Old December 18th, 2002, 05:24 PM   #10
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But the resulting footage is still interlaced, right?
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Old December 18th, 2002, 06:57 PM   #11
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both are still interlaced. the frame mode just has both fields shot more or less at the same time to give the illusion of deinterlacing. for 30fps, though, i'm sure it's interlaced, but i don't know what kind of processing it does that's why i'm concerned about quality. I don't think that little boost of light does not come at a price.

i prefer the 30fps because of the motion blur, but, of course, shoot at a faster shutter if i plan to slow down the video in post]

does anyone know how the 30fps is achieved?

another question is- what is the effect of the 30fps on depth of field?
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Old December 19th, 2002, 12:40 AM   #12
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Shutterspeed doesn't directly affect depth-of-field.

Although when you use a 1/30th shutter, you might need to close down the iris a bit to reduce the amount of light a bit. In THAT case, the depth-of-field increases, meaning a larger image area is in focus.

If you don't want that, you'll need to reduce the amount of light entering the lens by using ND filters and keeping the iris open.

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Old December 19th, 2002, 08:46 AM   #13
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"both are still interlaced. the frame mode just has both fields shot more or less at the same time to give the illusion of deinterlacing. "

No, frame mode video is not interlaced, at least not when imported into the computer. It is 30 distinct 720 x 480 frames per second which you can treat as film for rotoscoping, etc.
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Old December 19th, 2002, 09:01 AM   #14
 
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I beg to differ....frame mode is MOST CERTAINLY interlaced. You just can't see the interlacing because there are no temporal distortions.
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Old December 19th, 2002, 12:06 PM   #15
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barend,

I'm asking about depth of field in a situation where available light is compensated while the opening, focal length, distance of subject and background is kept constant to provide the same exposure for both the frame movie mode and 30fps effect
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