frame mode and 25fps

[Jean-Claude Nouchy]

Hi,

i come with an easy question.. i read somewhere that FRAME mode halve the resolution... is that true?

actually i use 1/25 for shutter to archieve a more film look picture and i was always in Frame mode... but since i read that i really looked, using a proper monitor, at the difference between images in Frame and in Normal (interlaced).. and the Frame picture actually looks less detailed, like slightly compressed..

i so changed my preferred setting to normal mode and I have a better image quality with Interlaced mode and using 1/25 shutter i have the SAME film effects.

waiting for your impressions :]

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Frame mode part II

working in Frame mode also gives me a problem... i Use Avid Xpress DV for my editings and i cant set the capture to be FRAME... it seams that capture works just in Fields (interlaced).. the result is that when i export a still frame (that was FRAME in my DV tape) it appears like half resolution in height.
in this example http://www.mimgfx.com/images/gallery/animals_7.jpg the tape is recorded in FRAME mode and this is one frame exported from AVID xpressDV in Frame mode and its visible the pixelation that comes out.

to export correctly i have to export in Field mode even if my source is frame. (hm... like it have to re-interlace frame so i'll have back again my Frame)

[Rob Lohman]

First of all if you shoot in frame mode it should not be too much
a problem if your software is still in interlaced. For a computer
the difference between interlaced and progressive is only a slight
time difference between two lines. That is all.

Personally I would use a shutter of 1/50 for PAL, I think that
looks better. And yes, if you use frame mode on the XL1/XL1s
it will reduce your quality (I don't use the word resolution here
cause the actual digital resolution will not change). You will loose
I think about 30% of the lines. Personally this is not a huge
problem for me, but that is personal ofcourse.

[Andre De Clercq]

Real frame mode (progressive) doesn't reduce vertical resolution. Setting 1/25 for shutter time however, means that every field is outputted two times in interlaced mode and forms a frame. Result: no motion feathering ( and the "filmlook" judder) but halved vertical resolution. The end result is exactly the same as what you get by deinterlacing by line repetition.

[Jean-Claude Nouchy]

Andre : are you saying XL1s have REAL frame mode?

Rob : Fields or Frame is really important for a Computer when integrating 3D is supposed to be part of the job. and more.. if you add texts like crowl or roll can be really different in Frame mode.
end titles saw at theater, if too small, cant be almost read. if you watch 'em on a monitor where playback is in FIELDS is really different. since we're talking about Field and frame i think we're talking about shooting that have to be watched on TV and not converted with telecine. on a TV effects, texts or CG graphics has to be made in fields for better result. as opposite, 3D integration can be really bad to be integrated if rendered in Fields where motion blur is computed in 3D.. cause motion blur in fields is incorrect.


sorry for this explaination that maybe can be misundersoud but i think that for a computer.. fields or frame are much more than slight time difference between lines. :]

obviouly i talk in this way cause i main use my XL1 for CG integration and i always have to think about rendering my 3D in field or in frame.

anyway.. i post here the page where i read about the Resolution thing in Frame mode


http://jkor.com/peter/tipstricks.html

"Specific Advise for the Canon XL-1:
I definitely don't use the "Movie Mode > Frame" setting on the Canon XL-1. It will halve your resolution, and introduce jerkiness, or a strobbing effect, with motion! ..... [cont]

[Andre De Clercq]

No Jeanclaude, the XL1s doesnt have real prog. scan. Many camcorders try to imitate pro scan...Canon XL1s is one of the best by using a kind of hybrid CCD readout, resulting in a less than halved vertical luma res. , and less jaggies. Vertical chroma res. is still being halved. Today the pana DVX100 offers real prog scan (not yet existing in PAL version)

[Rob Lohman]

I know exactly what the problem is with interlaced vs. progressive
and CGI for example. I've done some CG work myself in the past
so I know the perils. Basically interlaced is only a time difference,
that is the major problem. If you want to integrate CG footage
I would definitely shoot in frame mode. That saves you from a lot
of trouble lateron!

Real frame mode/progressive doesn't reduce your line resolution.
The frame mode on the XL1 does, because it is not true
progressive. Sorry.