Frame mode and panning

G. Randy Brown · October 14th, 2003, 07:29 AM

Thanks Andre;
>>the shutter speed is automatically set somewhat higher (1/100). Higher shutter speed makes stuttering more visible<<

So if I understand that statement, you feel turning off the EIS on the XL1S can actually make stuttering worse.
Thanks again,
Randy

Andre De Clercq · October 14th, 2003, 09:52 AM

No Randy, a small amount of motion blur is what you need for lowering the stutter visibility. EIS lowers blur and is best to be switched off. XL1 has optical stabilisation (OIS) I think, so it does't matter.

G. Randy Brown · October 16th, 2003, 03:58 PM

Sorry it took so long to get back to you Andre; so I guess I have 2 options:
1) don't pan (or do so very slowly)
2) switch to normal mode

Oh well, my thanks to everyone for your time, effort and patience.

Randy

Alex Dunn · October 29th, 2003, 02:35 PM

Can we get a clarification on the Canon being OIS or EIS? I ask because it actually states in the manual (or on the website somewhere) to remember to turn OFF the IS when panning because it will cause stuttering. That's straight from CANON. I'll try to find the info to backup my statement, but I'm pretty confident I didn't dream this up.

I think shutter speed variations can help your situation, I'd consider switching to NORMAL a last resort.

Alex Dunn · October 29th, 2003, 02:42 PM

Nevermind, it's definately Optical, but it does say to "Keep the image stabilizer turned off when the camera is mounted on a tripod." (page 40 of the XL1s manual)

Gints Klimanis · October 29th, 2003, 02:52 PM

I'm new to film, but not to digital signal processing. The panning rates depend on the resolution of the features of the subject and
the frame rate. Video is a three dimensional signal stream, with two dimensions in a frame and another dimension in time. To avoid aliasing in digital signals, the highest frequency must be 1/2 the sampling frequency. So, panning rates would be optimally determined by these rules of information processing.
However, optimal panning rates that don't alias (stutter, "shear", etc.) will probably err on the slow side.

Pan tables exist as guidelines, but it's pretty clear that
subjects that occupy a large % of the frame area with gradual feature changes will allow for faster pans while subjects with sharp feature changes that approach the video pixel size will need slower pans. Just try panning on a school yard fence/chicken wire. Slower shutter speeds will enable a general blur the motion over the frame, yielding smoother pans due to the averaging of information within a frame.

Alex Dunn · October 29th, 2003, 03:15 PM

Let me see if I can restate this:

The amount of aliasing is proportional to amount of movement (independent from the pan motion), where the aliasing increases as the independant motion decreases. And the size of the object in motion is also proportionate to the aliasing in that the aliasing decreases as the size of the object in motion increases.

Is that right?

G. Randy Brown · October 29th, 2003, 06:31 PM

Hmmm, so in other words, if you can't plan/rehearse your shot, either don't pan quickly or use normal mode : )
I do a weekly local TV show for a producer that loves the film look I can obtain with the XL1s; after my last post, when I explained to her that frame mode has the same attributes (drawbacks) as film she was understanding and so everything is cool.
Thanks for the replys guys,
Randy

Gints Klimanis · October 29th, 2003, 06:40 PM

Alex,

Yes, aliasing is proportional to the amount of movement / data rate. This "movement" is actually high frequency information. Sharp edges are constructed with higher frequencies, so fine features such as wires will need slower panning/zoom rates.

Aliasing, if it occurs at all, decreases as the information bandwidth decreases. Objects with softer edges will alias less and allow faster panning/zoom rates.

Gints Klimanis · October 29th, 2003, 06:45 PM

G. Randy Brown,

Yes, we are guilty of trying to understand the limits of panning and zooming. I believe it is possible for a camera to
offer warnings on panning and zooming, especially when HD cameras will be used to produce SD video. Using zebra bars or something, the display where the aliasing will occur. This would be yet another tool to help rehearse camera moves.

G. Randy Brown · October 30th, 2003, 08:20 AM

Thanks Gints.
Randy

October 14th, 2003, 07:29 AM	#16
G. Randy Brown Major Player Join Date: Jan 2003 Location: Las Cruces, NM Posts: 288	Thanks Andre; >>the shutter speed is automatically set somewhat higher (1/100). Higher shutter speed makes stuttering more visible<< So if I understand that statement, you feel turning off the EIS on the XL1S can actually make stuttering worse. Thanks again, Randy

October 14th, 2003, 09:52 AM	#17
Andre De Clercq Major Player Join Date: Sep 2002 Location: Belgium Posts: 804	No Randy, a small amount of motion blur is what you need for lowering the stutter visibility. EIS lowers blur and is best to be switched off. XL1 has optical stabilisation (OIS) I think, so it does't matter.

October 16th, 2003, 03:58 PM	#18
G. Randy Brown Major Player Join Date: Jan 2003 Location: Las Cruces, NM Posts: 288	Sorry it took so long to get back to you Andre; so I guess I have 2 options: 1) don't pan (or do so very slowly) 2) switch to normal mode Oh well, my thanks to everyone for your time, effort and patience. Randy

October 29th, 2003, 02:35 PM	#19
Alex Dunn Major Player Join Date: Aug 2002 Location: Phoenix, AZ Posts: 202	Can we get a clarification on the Canon being OIS or EIS? I ask because it actually states in the manual (or on the website somewhere) to remember to turn OFF the IS when panning because it will cause stuttering. That's straight from CANON. I'll try to find the info to backup my statement, but I'm pretty confident I didn't dream this up. I think shutter speed variations can help your situation, I'd consider switching to NORMAL a last resort.

October 29th, 2003, 02:42 PM	#20
Alex Dunn Major Player Join Date: Aug 2002 Location: Phoenix, AZ Posts: 202	Nevermind, it's definately Optical, but it does say to "Keep the image stabilizer turned off when the camera is mounted on a tripod." (page 40 of the XL1s manual)

October 29th, 2003, 02:52 PM	#21
Gints Klimanis Inner Circle Join Date: Jun 2003 Location: San Jose, CA Posts: 2,222	I'm new to film, but not to digital signal processing. The panning rates depend on the resolution of the features of the subject and the frame rate. Video is a three dimensional signal stream, with two dimensions in a frame and another dimension in time. To avoid aliasing in digital signals, the highest frequency must be 1/2 the sampling frequency. So, panning rates would be optimally determined by these rules of information processing. However, optimal panning rates that don't alias (stutter, "shear", etc.) will probably err on the slow side. Pan tables exist as guidelines, but it's pretty clear that subjects that occupy a large % of the frame area with gradual feature changes will allow for faster pans while subjects with sharp feature changes that approach the video pixel size will need slower pans. Just try panning on a school yard fence/chicken wire. Slower shutter speeds will enable a general blur the motion over the frame, yielding smoother pans due to the averaging of information within a frame.

October 29th, 2003, 03:15 PM	#22
Alex Dunn Major Player Join Date: Aug 2002 Location: Phoenix, AZ Posts: 202	Let me see if I can restate this: The amount of aliasing is proportional to amount of movement (independent from the pan motion), where the aliasing increases as the independant motion decreases. And the size of the object in motion is also proportionate to the aliasing in that the aliasing decreases as the size of the object in motion increases. Is that right?

October 29th, 2003, 06:31 PM	#23
G. Randy Brown Major Player Join Date: Jan 2003 Location: Las Cruces, NM Posts: 288	Hmmm, so in other words, if you can't plan/rehearse your shot, either don't pan quickly or use normal mode : ) I do a weekly local TV show for a producer that loves the film look I can obtain with the XL1s; after my last post, when I explained to her that frame mode has the same attributes (drawbacks) as film she was understanding and so everything is cool. Thanks for the replys guys, Randy

October 29th, 2003, 06:40 PM	#24
Gints Klimanis Inner Circle Join Date: Jun 2003 Location: San Jose, CA Posts: 2,222	Alex, Yes, aliasing is proportional to the amount of movement / data rate. This "movement" is actually high frequency information. Sharp edges are constructed with higher frequencies, so fine features such as wires will need slower panning/zoom rates. Aliasing, if it occurs at all, decreases as the information bandwidth decreases. Objects with softer edges will alias less and allow faster panning/zoom rates.

October 29th, 2003, 06:45 PM	#25
Gints Klimanis Inner Circle Join Date: Jun 2003 Location: San Jose, CA Posts: 2,222	G. Randy Brown, Yes, we are guilty of trying to understand the limits of panning and zooming. I believe it is possible for a camera to offer warnings on panning and zooming, especially when HD cameras will be used to produce SD video. Using zebra bars or something, the display where the aliasing will occur. This would be yet another tool to help rehearse camera moves.

October 30th, 2003, 08:20 AM	#26
G. Randy Brown Major Player Join Date: Jan 2003 Location: Las Cruces, NM Posts: 288	Thanks Gints. Randy