Wow... Rolling shutter

Tom Hardwick · June 17th, 2009, 08:02 AM

Quote:

Originally Posted by Ken Ross

Why were people 'perfectly content' with total frames that were obliterated?

I don't think people ever were, Ken. What I like about the way CCDs handle electronic flash is the way you get a 'starburst' effect from each little flashgun as you swing round to film the paparazzi blitzing the cake cutting, for instance.

When I've shot with CMOS, each flash as bleached out a (constantly different) proportion of its resultant frame.

tom.

Alex Khachatryan · November 16th, 2009, 11:36 PM

Hi. I went throw all topic and got a little bit scared. But understanding the possible issue is a good cause to get ready to avoid it.
I have a question. I am going to shoot a fire performer in a dark environment with my Z5 and there are going to be a lot of flames out there, some will be short and some long lasting. Of course fire flames are not the same as flash strikes but is it possible that I may face the rolling shutter issue afterwards? Any experience that involved fire flame shooting will be deeply appreciated.

Jeff Harper · November 17th, 2009, 12:13 AM

should be no problem, flames will not create rolling shutter.

Tom Hardwick · November 17th, 2009, 02:07 AM

The steadier you can keep a CMOS chipped camera the better, and this has to do with the rolling shutter (RS) rather than the image stabilisation. See

YouTube - HV30 stabilisation problems part 2

This next EX1 RS demo doesn't show how bad RS is in practice. Why? Because the footage in this clip

http://www.youtube.com/watch?v=N1pFa...eature=related

is only correctly exposed when the electronic flashes fire - all the rest of the time the dance is under-exposed.

When I've used an EX1 in such conditions I've correctly exposed the scene, only to have electronic flashes burn the partial frames out to complete nuclear-explosion white - and it looks a lot worse than shown here.

tom.

Alex Khachatryan · November 18th, 2009, 04:40 PM

Thank you, will see results in few days from now.
Tom, second link is broken.

Tom Hardwick · November 19th, 2009, 02:40 AM

Alex, try this link - it works for me

YouTube - Sony PMW-EX1 Rolling Shutter Demo

Alex Khachatryan · November 19th, 2009, 10:41 AM

Quote:

Originally Posted by Tom Hardwick

This next EX1 RS demo doesn't show how bad RS is in practice. Why? Because the footage in this clip

http://www.youtube.com/watch?v=N1pFa...eature=related

is only correctly exposed when the electronic flashes fire - all the rest of the time the dance is under-exposed.

When I've used an EX1 in such conditions I've correctly exposed the scene, only to have electronic flashes burn the partial frames out to complete nuclear-explosion white - and it looks a lot worse than shown here.

tom.

Thank you Tom. This is a great example.

Dave Blackhurst · November 19th, 2009, 11:04 AM

A couple comments are in order - the first clip illustrates problems with an HV30 consumer grade camera - and it's a KNOWN problem with some HV series cameras - google "jello" and Canon... the "test methodology" only shows one thing - that particular Canon had issues. When I had an HV20, I never saw anything that bad, but I can see how it could happen. The most glaring flaw in the "test" is that the HC3 he compares to is a CMOS camera as well... duh, it's NOT the sensor that's the problem.

AS for the second clip, it looks like it's probably STROBE LIGHTS, not flashes (yes the problems are similar). I shot some footage under similar conditions with a smaller cam with CMOS, and yes it looked "bad"... was I surprised... NO, the lighting conditions were atrocious. Partial frame flash exposures aren't great, but there are a lot of plusses with CMOS IMO, and like anything else, it's a tradeoff.

Don't expect to go into environments with strobes or lots of flashes and not see the "problem", but don't condemn the cameras or the technology because those conditions are challenging and create difficult issues...

Jeff Harper · November 19th, 2009, 01:04 PM

I just finished what was probably my 30th wedding shot with my FX1000s. One thing I'll say for CCD chips is that flashes look like flashes. They look the way they are supposed to look, a flash of bright light. With CMOS chips sometimes flashes can give the appearance of defective video...the half frame coverage looks weird, and there is no other way to describe it.

Most of the time it is not a big deal, but on occasion, particularly when the bride is coming down the aisle, the half frame coverage is so pronounced and odd that it is disturbing.

I've never understood videographers that hated the way flashes look on a CCD camera, because you are videotaping the action, and flashes are part of that. I much prefer all of the flash to half of it.

Tom Hardwick · November 19th, 2009, 01:50 PM

I agree Jeff, the way CCDs handle electronic flash comes out looking like how I'd fake a flash. I've done this at times because sometimes I've had a shot of the couple cutting the cake (for instance) where no-body's taken any pictures, and it kinds looks 'bare' and the couple look a bit feeble just standing there, posing. Easy enough to add some SLR clicks to the audio track, too.

So I add flash frames easily on the timeline and it suddenly puts the couple in the paparazzi spotlight, makes them look more like stars on the red carpet. Thing is I'd never in my wildest dreams add a ½ over-exposed frame here, a ¼ over-exposed frame there - it just isn't on.

Dave's right - CMOS is here to stay and the technology brings with it advantages as well as disadvantages. Sony's clip browser sounds as if it'll even up thses badly exposed CMOS flash frames, so as always, the technology improves all the time.

tom.

November 16th, 2009, 11:36 PM	#92
Alex Khachatryan Regular Crew Join Date: Oct 2009 Location: Brooklyn, NY Posts: 134	Hi. I went throw all topic and got a little bit scared. But understanding the possible issue is a good cause to get ready to avoid it. I have a question. I am going to shoot a fire performer in a dark environment with my Z5 and there are going to be a lot of flames out there, some will be short and some long lasting. Of course fire flames are not the same as flash strikes but is it possible that I may face the rolling shutter issue afterwards? Any experience that involved fire flame shooting will be deeply appreciated.

November 17th, 2009, 12:13 AM	#93
Jeff Harper Inner Circle Join Date: Jun 2005 Location: Cincinnati, OH Posts: 8,425	should be no problem, flames will not create rolling shutter.

November 17th, 2009, 02:07 AM	#94
Tom Hardwick Inner Circle Join Date: Mar 2003 Location: Billericay, England UK Posts: 4,711	The steadier you can keep a CMOS chipped camera the better, and this has to do with the rolling shutter (RS) rather than the image stabilisation. See YouTube - HV30 stabilisation problems part 2 This next EX1 RS demo doesn't show how bad RS is in practice. Why? Because the footage in this clip http://www.youtube.com/watch?v=N1pFa...eature=related is only correctly exposed when the electronic flashes fire - all the rest of the time the dance is under-exposed. When I've used an EX1 in such conditions I've correctly exposed the scene, only to have electronic flashes burn the partial frames out to complete nuclear-explosion white - and it looks a lot worse than shown here. tom.

November 18th, 2009, 04:40 PM	#95
Alex Khachatryan Regular Crew Join Date: Oct 2009 Location: Brooklyn, NY Posts: 134	Thank you, will see results in few days from now. Tom, second link is broken.

November 19th, 2009, 02:40 AM	#96
Tom Hardwick Inner Circle Join Date: Mar 2003 Location: Billericay, England UK Posts: 4,711	Alex, try this link - it works for me YouTube - Sony PMW-EX1 Rolling Shutter Demo

November 19th, 2009, 11:04 AM	#98
Dave Blackhurst Inner Circle Join Date: Feb 2007 Location: Apple Valley CA Posts: 4,874	A couple comments are in order - the first clip illustrates problems with an HV30 consumer grade camera - and it's a KNOWN problem with some HV series cameras - google "jello" and Canon... the "test methodology" only shows one thing - that particular Canon had issues. When I had an HV20, I never saw anything that bad, but I can see how it could happen. The most glaring flaw in the "test" is that the HC3 he compares to is a CMOS camera as well... duh, it's NOT the sensor that's the problem. AS for the second clip, it looks like it's probably STROBE LIGHTS, not flashes (yes the problems are similar). I shot some footage under similar conditions with a smaller cam with CMOS, and yes it looked "bad"... was I surprised... NO, the lighting conditions were atrocious. Partial frame flash exposures aren't great, but there are a lot of plusses with CMOS IMO, and like anything else, it's a tradeoff. Don't expect to go into environments with strobes or lots of flashes and not see the "problem", but don't condemn the cameras or the technology because those conditions are challenging and create difficult issues...

November 19th, 2009, 01:04 PM	#99
Jeff Harper Inner Circle Join Date: Jun 2005 Location: Cincinnati, OH Posts: 8,425	I just finished what was probably my 30th wedding shot with my FX1000s. One thing I'll say for CCD chips is that flashes look like flashes. They look the way they are supposed to look, a flash of bright light. With CMOS chips sometimes flashes can give the appearance of defective video...the half frame coverage looks weird, and there is no other way to describe it. Most of the time it is not a big deal, but on occasion, particularly when the bride is coming down the aisle, the half frame coverage is so pronounced and odd that it is disturbing. I've never understood videographers that hated the way flashes look on a CCD camera, because you are videotaping the action, and flashes are part of that. I much prefer all of the flash to half of it.

November 19th, 2009, 01:50 PM	#100
Tom Hardwick Inner Circle Join Date: Mar 2003 Location: Billericay, England UK Posts: 4,711	I agree Jeff, the way CCDs handle electronic flash comes out looking like how I'd fake a flash. I've done this at times because sometimes I've had a shot of the couple cutting the cake (for instance) where no-body's taken any pictures, and it kinds looks 'bare' and the couple look a bit feeble just standing there, posing. Easy enough to add some SLR clicks to the audio track, too. So I add flash frames easily on the timeline and it suddenly puts the couple in the paparazzi spotlight, makes them look more like stars on the red carpet. Thing is I'd never in my wildest dreams add a ½ over-exposed frame here, a ¼ over-exposed frame there - it just isn't on. Dave's right - CMOS is here to stay and the technology brings with it advantages as well as disadvantages. Sony's clip browser sounds as if it'll even up thses badly exposed CMOS flash frames, so as always, the technology improves all the time. tom.