What do you think this is? Rolling shutter issue? at DVinfo.net

Kaku Ito · December 9th, 2007, 10:22 PM

After shooting around late at night with EX1, felt amazed with the low light situation (the best ever after various affordable cams), I thought this one one of the shot that demonstrates the amazing capabilities of EX1 with 1080/24p over 30 frame and the light sensitivities...., but I found out in the post, there is something wrong when a man with bag crossed in front of the camera. The shape of the taxi behind gets distorted.

Anyone can suggest to make it not happen?

http://web.mac.com/kakuito/KakugyoBl...1_study_1.html

Leonard Levy · December 9th, 2007, 11:23 PM

I can't see what you are talking about. Is this the yellow taxi that changes shape? When? What guy with a bag?

Sorry I just don't seee anything. maybe i'm looking in the worng place.

Pasty Jackson · December 9th, 2007, 11:27 PM

I see what you're talking about, Kaku. It's got nothing to do with rolling shutter. It's actually the lens breathing because it's on auto-focus. The moment the man crosses in front of the camera, you can see the focus plane change from the taxi to the foreground as it searches for something to focus on. This is certainly weird looking, but again has nothing to do with the rolling shutter.

Serena Steuart · December 9th, 2007, 11:27 PM

I've watched that clip many times and still haven't seen the artifact you have noted; difficult to precisely identify which is the man-with-the-bag, since there are many. Timecode is a useful thing. I do note that the taxi arriving isn't distorted and that the taxi in the rear moves as someone gets in or out. A stationary object cannot be distorted by a shutter (rolling or otherwise).

Serena Steuart · December 9th, 2007, 11:33 PM

Quote:

Originally Posted by Pasty Jackson

I see what you're talking about, Kaku. It's got nothing to do with rolling shutter. It's actually the lens breathing because it's on auto-focus. The moment the man crosses in front of the camera, you can see the focus plane change from the taxi to the foreground as it searches for something to focus on. This is certainly weird looking, but again has nothing to do with the rolling shutter.

Are you speaking of taxi 1125, which bobs as it stops. Wasn't the camera on manual focus?

Pasty Jackson · December 9th, 2007, 11:41 PM

Ok, just watched it again. The area in question is early in the clip, just before the taxi enters the scene. You can see the focus plane changing at that moment, but it doesn't change as dramatically as I assumed... it does look to be manually focused. It is a strange anomaly, but I'm still quite sure it is unrelated to the rolling shutter.

Theory: the man that passes in front of the camera is, firstly, out of focus - which essentially blurs him. Secondly, he is swinging his arms as he walks in front of the car. The movement in the blurred foreground makes the car look distorted. It's similar to closing one eye, looking at the horizon, holding a pencil up horizontally in front of your eye, and moving it up and down while still focusing on the horizon... the horizon around the pencilo seems to bend and distort.

Just a guess that it was pure circumstance and not shutter-related. Essentially, light diffraction.

Pasty Jackson · December 10th, 2007, 12:15 AM

Here's a simplistic, but easy to understand example:
http://www.ngsir.netfirms.com/englis...ffraction2.htm

Light waves (or rays) react in the same manner when an obstacle is introduced.

And... one more cheesy example:
http://www.exploratorium.edu/snacks/diffraction.html

Kaku Ito · December 10th, 2007, 01:21 AM

Okay, right now I don't have the time to read all of your responses, but this wasn't shot with autofocus. I was playing around with the focus between the people and the taxies. But no autofocus. As matter of the fact, I couldn't figure out to do autofocus until later (didn't know about the ring slide function).

If this thing gets figure out, EX1 should be really excellent.

I will look into more clips to see if any similar thing happened but over all, EX1 shows its ability to shoot video that other cams would have hard time.

And please, don't take it personal people. I'm not attacking EX1 particularly. I understand people don't want to hear about bad things to new star in the industry, but it is good to know how to avoid these things. The issue looks like similar problems I had with HV20 that the picture becomes wobbly, like elastic (excuse my limited expressions here).

I don't know what happened to all of that "you are greatest" and all that encouragements when I provided FX1 and Canon cam clips. I got a person posting "disturbing" on to my blog.
I think I'm going to quit all of this effort now.

Kaku Ito · December 10th, 2007, 01:32 AM

Quote:

Originally Posted by Pasty Jackson

Here's a simplistic, but easy to understand example:
http://www.ngsir.netfirms.com/englis...ffraction2.htm

Light waves (or rays) react in the same manner when an obstacle is introduced.

And... one more cheesy example:
http://www.exploratorium.edu/snacks/diffraction.html

Pasty, that's a good one.

Eric Pascarelli · December 10th, 2007, 01:33 AM

Ito,

I think that this effect would happen with any camera, not just the EX1.

I think there is nothing to be concerned about.

Serena Steuart · December 10th, 2007, 02:28 AM

Quote:

Originally Posted by Pasty Jackson

Here's a simplistic, but easy to understand example:
http://www.ngsir.netfirms.com/englis...ffraction2.htm

Light waves (or rays) react in the same manner when an obstacle is introduced.

And... one more cheesy example:
http://www.exploratorium.edu/snacks/diffraction.html

No, diffraction isn't relevant at this scale! Certainly not the appropriate phenomenon.

Don't think anyone is upset if there is a problem with the EX, which of course people want to know about. It's just that this doesn't look like a problem.

Kaku Ito · December 10th, 2007, 02:45 AM

Even if there's an issue with rolling shutter (I'm not saying there is at this moment then), EX1 seems to overcome many other affordable HD cam issues, so I don't think it will influence the popularity at all.

With my dog clip, you can see some skateboard video shooters would come up with some great footage, even at night at low light situation.

The noise level don't look that much problem when the gain was up and the stabilizer works really well, too. I think that should be helping the compression a great deal.

Dean Sensui · December 10th, 2007, 04:31 AM

Kaku...

That EX1, from this first impression, looks very good in low light.

Right now I'm still shooting with an HVX-200 but was looking at the EX1 as a second camera for the fishing show. In fact, if it does well enough, it will probably be the primary camera since it records a lot more material per gigabyte at 1080p30 than the HVX.

BTW, I'm working with Audy to do a bunch of production work, and he is also joining the company that produces the fishing show. If we're lucky we can get a chance to look at a demo EX1 from Sony.

Sami Sanpakkila · December 10th, 2007, 05:10 AM

At the risk of sounding stupid. It looks to me that the camera is moving to the left simultaneously as the man passes in front and this makes the taxi look like its skewing because it stays in the frame longer then one would expect if the camera would have been stationary. If the man had not passed the camera at this point I doubt there would be anything funny looking in the taxi.

The footage looks really nice!! Would love to see more!

Sami

Sergio Barbosa · December 10th, 2007, 05:32 AM

my bet is on the mpeg compression... that element on the frame may be interpolated.

December 9th, 2007, 10:22 PM	#1
Kaku Ito Trustee Join Date: Jun 2004 Location: Chiyoda-ku, Tokyo Posts: 1,382	What do you think this is? Rolling shutter issue? After shooting around late at night with EX1, felt amazed with the low light situation (the best ever after various affordable cams), I thought this one one of the shot that demonstrates the amazing capabilities of EX1 with 1080/24p over 30 frame and the light sensitivities...., but I found out in the post, there is something wrong when a man with bag crossed in front of the camera. The shape of the taxi behind gets distorted. Anyone can suggest to make it not happen? http://web.mac.com/kakuito/KakugyoBl...1_study_1.html

December 10th, 2007, 04:31 AM	#13
Dean Sensui Inner Circle Join Date: Oct 2001 Location: Honolulu, HI Posts: 2,054	Kaku... That EX1, from this first impression, looks very good in low light. Right now I'm still shooting with an HVX-200 but was looking at the EX1 as a second camera for the fishing show. In fact, if it does well enough, it will probably be the primary camera since it records a lot more material per gigabyte at 1080p30 than the HVX. BTW, I'm working with Audy to do a bunch of production work, and he is also joining the company that produces the fishing show. If we're lucky we can get a chance to look at a demo EX1 from Sony. __________________ Dean Sensui Exec Producer, Hawaii Goes Fishing

December 9th, 2007, 11:23 PM	#2
Leonard Levy Trustee Join Date: Feb 2006 Location: USA Posts: 1,684	I can't see what you are talking about. Is this the yellow taxi that changes shape? When? What guy with a bag? Sorry I just don't seee anything. maybe i'm looking in the worng place.

December 9th, 2007, 11:27 PM	#3
Pasty Jackson Regular Crew Join Date: Aug 2003 Location: Asheville, NC Posts: 47	I see what you're talking about, Kaku. It's got nothing to do with rolling shutter. It's actually the lens breathing because it's on auto-focus. The moment the man crosses in front of the camera, you can see the focus plane change from the taxi to the foreground as it searches for something to focus on. This is certainly weird looking, but again has nothing to do with the rolling shutter.

December 9th, 2007, 11:27 PM	#4
Serena Steuart Major Player Join Date: Jun 2006 Location: Studio Alnitak, Melbourne, Victoria, Australia Posts: 640 Images: 3	I've watched that clip many times and still haven't seen the artifact you have noted; difficult to precisely identify which is the man-with-the-bag, since there are many. Timecode is a useful thing. I do note that the taxi arriving isn't distorted and that the taxi in the rear moves as someone gets in or out. A stationary object cannot be distorted by a shutter (rolling or otherwise).

December 9th, 2007, 11:41 PM	#6
Pasty Jackson Regular Crew Join Date: Aug 2003 Location: Asheville, NC Posts: 47	Ok, just watched it again. The area in question is early in the clip, just before the taxi enters the scene. You can see the focus plane changing at that moment, but it doesn't change as dramatically as I assumed... it does look to be manually focused. It is a strange anomaly, but I'm still quite sure it is unrelated to the rolling shutter. Theory: the man that passes in front of the camera is, firstly, out of focus - which essentially blurs him. Secondly, he is swinging his arms as he walks in front of the car. The movement in the blurred foreground makes the car look distorted. It's similar to closing one eye, looking at the horizon, holding a pencil up horizontally in front of your eye, and moving it up and down while still focusing on the horizon... the horizon around the pencilo seems to bend and distort. Just a guess that it was pure circumstance and not shutter-related. Essentially, light diffraction.

December 10th, 2007, 12:15 AM	#7
Pasty Jackson Regular Crew Join Date: Aug 2003 Location: Asheville, NC Posts: 47	Here's a simplistic, but easy to understand example: http://www.ngsir.netfirms.com/englis...ffraction2.htm Light waves (or rays) react in the same manner when an obstacle is introduced. And... one more cheesy example: http://www.exploratorium.edu/snacks/diffraction.html

December 10th, 2007, 01:21 AM	#8
Kaku Ito Trustee Join Date: Jun 2004 Location: Chiyoda-ku, Tokyo Posts: 1,382	Okay, right now I don't have the time to read all of your responses, but this wasn't shot with autofocus. I was playing around with the focus between the people and the taxies. But no autofocus. As matter of the fact, I couldn't figure out to do autofocus until later (didn't know about the ring slide function). If this thing gets figure out, EX1 should be really excellent. I will look into more clips to see if any similar thing happened but over all, EX1 shows its ability to shoot video that other cams would have hard time. And please, don't take it personal people. I'm not attacking EX1 particularly. I understand people don't want to hear about bad things to new star in the industry, but it is good to know how to avoid these things. The issue looks like similar problems I had with HV20 that the picture becomes wobbly, like elastic (excuse my limited expressions here). I don't know what happened to all of that "you are greatest" and all that encouragements when I provided FX1 and Canon cam clips. I got a person posting "disturbing" on to my blog. I think I'm going to quit all of this effort now.

December 10th, 2007, 01:33 AM	#10
Eric Pascarelli Major Player Join Date: Nov 2007 Location: Los Angeles, CA Posts: 498	Ito, I think that this effect would happen with any camera, not just the EX1. I think there is nothing to be concerned about.

December 10th, 2007, 02:45 AM	#12
Kaku Ito Trustee Join Date: Jun 2004 Location: Chiyoda-ku, Tokyo Posts: 1,382	Even if there's an issue with rolling shutter (I'm not saying there is at this moment then), EX1 seems to overcome many other affordable HD cam issues, so I don't think it will influence the popularity at all. With my dog clip, you can see some skateboard video shooters would come up with some great footage, even at night at low light situation. The noise level don't look that much problem when the gain was up and the stabilizer works really well, too. I think that should be helping the compression a great deal.

December 10th, 2007, 05:10 AM	#14
Sami Sanpakkila Major Player Join Date: Nov 2007 Location: Finland Posts: 317	At the risk of sounding stupid. It looks to me that the camera is moving to the left simultaneously as the man passes in front and this makes the taxi look like its skewing because it stays in the frame longer then one would expect if the camera would have been stationary. If the man had not passed the camera at this point I doubt there would be anything funny looking in the taxi. The footage looks really nice!! Would love to see more! Sami

December 10th, 2007, 05:32 AM	#15
Sergio Barbosa Regular Crew Join Date: May 2006 Location: Portugal Posts: 140	my bet is on the mpeg compression... that element on the frame may be interpolated.