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video jello

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markowp7

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i tried te 5D mark II today in canon's tokyo shinjuku demo area. nice camera, good feel (it was new for me, i have never handled the 5D before). the nice lady let me try out the video function and i immediately tried out whether it produces the jello effect. it turned out that is was easy to get, just by (not even very fast) panning. i made a column in the shop wobble by just panning left and right around it. no miracles there, CMOS is CMOS after all.
unfortunatly i could not take shots on my CF card, the CF door was taped....
i am sure that it will be a great camera.
peter
 
OK now we have conflicting stories. I don't doubt the posters claims, but we have had numerous claims to the contrary. We also have seen with our own eyes Reverie. Vincent claimed no ghosting as well.

I guess we may not know the truth until we try them ourselves?
 
i did not check ghosting effects (i could only replay the footage on the camera's display, not on my eizo screen--))), but a wobbling column is hard to overlook even on a tiny LCD.
peter
 
The "rolling shutter" is a problem with this type of technology. It causes two effects:
  • wobbly images with horizontal pans
  • squishing effect with vertical rapid movements
There is no solution to that and the only thing to do is to deal with it minimizing rapid camera motion. "Reverie" has some of the "squishing" (very little) and no obvious "wobbling" effect. Still I am pretty positive that the author had probably to throw away some footage because of too much of either on of the two effects.

He hasn't changed color or exposure or added any special effects, but he has obviously edited the video (cutting and pasting tracks into a final edit). His purpose was to show off the incredible low light qualities of this camera and of course he must have removed any footage that showed excessive "rolling shutter" issues.
 
From what I can see, Canon seem to have done a fantastic job in masking the effect.

--
'The majesticness of that duck is overwhelming!' - Bulbol
 
canon may have masked it well, yes, this may be true. i did NOT compare with the nikon D90!!! all i said was that with not too fast panning (which still may not be your video action of choice) you can produce very ugly jello effects on the 5D Mark II. in my view this does not diminish the value of the camera.
peter
 
The question is not a qualitative one (does it have rolling shutter artefacts, yes, and so do top notch movie cameras and always did).

The question is quantitative : What is really the speed of the rolling shutter and only Canon knows that precicely now. The general impression you can consistently read so far that it should be significantly less than D90. Of course, if you want to expose the rolling shutter, that is not difficult. The question is, how difficult is it not to expose it.

There are a few scenes in Laforet's video, where, comparing successive frames, you can see rolling shutter artefacts. It is pretty much impossible to be sure of them when watching the movie at 30fps.

I think a test setup should be feasible to actually measure the speed of the rolling shutter. Then, you can compare.

To be clear, the time required by the rolling shutter to traverse the frame must obviously be inferiour to the exposure time, but it can in principle be arbitrarily fast.
 
I don't think the camera is designed to be shaken around like those on funniest home videos. But then I'm sure funniest home videos will happily accept files of dogs and cats from the MkII.

For steady quick panning, the jello effect is negligible under normal viewing.
markowp7 said:
canon may have masked it well, yes, this may be true. i did NOT
compare with the nikon D90!!! all i said was that with not too fast
panning (which still may not be your video action of choice) you can
produce very ugly jello effects on the 5D Mark II. in my view this
does not diminish the value of the camera.
peter
Click to expand...
--
'The majesticness of that duck is overwhelming!' - Bulbol
 
I don't think the LCD would be the best place to accurately assess this. I'm not saying it doesn't exist, but the 30 FPS live view mode probably exaggerates it.
 
Keep in mind the LCD may not update at the same rate as the video encoding, thus greatly amplifying any effect. The true test would be to see the video itself after its written to the CF card.

--
Chris Rake, Austin Texas
Personal Gallery and Central Texas Photo Guide
http://crakephoto.com
 
What does CMOS have to do with this?

I suspect the shutter (see Lartiques' photo in the below):

http://www.wrotniak.net/photo/tech/fp-shutter.html
markowp7 said:
i tried te 5D mark II today in canon's tokyo shinjuku demo area. nice
camera, good feel (it was new for me, i have never handled the 5D
before). the nice lady let me try out the video function and i
immediately tried out whether it produces the jello effect. it turned
out that is was easy to get, just by (not even very fast) panning. i
made a column in the shop wobble by just panning left and right
around it. no miracles there, CMOS is CMOS after all.
unfortunatly i could not take shots on my CF card, the CF door was
taped....
i am sure that it will be a great camera.
peter
Click to expand...
 
the user is shaking the camera like a rag doll.... I don't know about what movies/documentaries you've seen much of that style of shooting. I know that certain people get a sort of motion sickness when viewing such videos. Movies like Dancer in the Dark or The Blair Witch Project have a handheld feeling that doesn't sit well with some.

If used properly, or more like a standard video camera, it appears to perform nicely (as per Vincent Laforet's video). Also, if a wide angle lens is used, you'll get a pseudo wobble effect with the extreme warping angles (just walking around eye glued to a 17mm lens is enough to be sick hehe).

All in all, yes there appears to be a wobble because of the CMOS, but how much can it tolerate in "normal" conditions.... waits to be seen.

--
Vadim
http://www.epicmind.com
 
Greg Pavlov said:
What does CMOS have to do with this?
Click to expand...
The simplest way to get video on a CMOS sensor is to implement a rolling shutter (the same readout mechanism normally used to read the sensor). The readout speeds of typical CMOS sensors means that there will be motion artifacts.

People incorrectly think that this simple implementation is necessary or required for CMOS. There are ways to avoid this by, for example, using a global shutter. This is done for high speed CMOS machine vision cameras. However, there are disadvantages to this approach because a global shutter requires extra circuitry at each pixel. Another approach might be to parallelize the readout in some way to increase the speed of the rolling shutter to the point where there aren't many artifacts.

--
Ron Parr
Digital Photography FAQ: http://www.cs.duke.edu/~parr/photography/faq.html
Gallery: http://www.pbase.com/parr/
 
Greg Pavlov said:
What does CMOS have to do with this?
Click to expand...
A lot. It's in the way the chip contents is read out and it's different with CMOS and CCD's.

Borek
 
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