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richard ladkani
Sony EX1 Severe LongGop Problems
on May 25, 2008 at 10:40:54 am

Hi

I recently tested the Ex1 to the Sony HVR Z7 to the Panasonic HVX201AE and found some very interesting problems regarding the EX1. We shot all kinds of scenes incl. Indoors, Outdoors, Sunset, Dusk all in 25p...and watched all the results on a Baselight System projected in 2k on a big cinema screen. The tests were done for an upcoming cinema documentary.

At first we all loved the EX1 for sharpness, latitude, color rendition and especially for its low-light capabilities. But all this love went away when we looked at shots were the camera moved. On slow pans across f.e. a green grass in the foreground and a city in the background the image suddenly went totally blury. At first we thought the camera was out of focus but as soon as the camera stopped the stellar sharpness was back. On the next telephoto pan across the city skyline all detail was lost as long as the camera moved. It was just a big blur. But it wasn't motion blurr due to the 25p it was a compression issue. On a shot watching cars drive through the frame the cars looked like ghost images. Totally unsharp but when I started panning with the cars the were totally sharp again. What was the worst though was panning across a field of grass. All detail was gone as long as the camera moved and it was back when the camera stopped. But the killer was when shooting handheld on a second day of tests. The person was walking and as log as he moved with the camera everyting wa fine but as soon as the camera would move out of sync with the person he went blurry.Again it did not look like motion blur. When looking at it in single frames we noticed that only every 8th frame was totally sharp everything else was blurred. We compared all this to identical shots with a Sony HVR Z7 on HDV and the problem was negligible. You could see some motion blurs but nothing that would feel unnatural. The images on the Z7 remained sharp throughout much of the shots even though both cameras use LongGop encoding. When contemplating about this problems my conclusion is that the EX1 due to its higher resolution also has a stronger compression. When the camera starts moving the compression suddenly kicks in and makes it highly visible. Even minor, very slow movements cause this problem. We watched the footage on a 25foot screen which made it highly visible but even on a 42" Plasma a home it was very noticeable. I am deeply disappointed about this as this LongGop Issue makes the EX1 unusable for big screen projects. The HDV performed much better even though it didn't have the latitude. But compared on a splitscreen with the EX1 it seems to be the better choice.

Has anybody seen this problem or any thoughts about it? I would have preferred the EX1 because it also offer 60p slowmo and is very good in low light. But I can't live with these blurr issues unless some solution is found.

Best wishes

Richard Ladkani


http://www.richardladkani.com


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Jeffrey Cirbes
Re: Sony EX1 Severe LongGop Problems
on May 25, 2008 at 2:44:56 pm

What were the shutter settings on the respective cams?



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Steve Connor
Re: Sony EX1 Severe LongGop Problems
on May 25, 2008 at 5:01:22 pm

This is a non issue and probably related to setup on the camera, we recently shot at an airshow in the UK with lots of fast pans while following aircraft taking of and landing and this effect did not happen. There has been a lot of debate about it on other forums

See this comparison between a pan on an F350 which does not have this issue and an EX1.

http://www.ingenioustv.com/clips/ex1-motion-test.mov

I'm guessing shutter settings without seeing an example.



Steve Connor
Adrenalin Television

Have you tried "Search Posts"? Enlightenment may be there.


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richard ladkani
Re: Sony EX1 Severe LongGop Problems
on May 25, 2008 at 9:34:24 pm

To Steve Connor

I just watched your clip of a car moving by. It has the same problems. The car remains sharp whereas the grass and the trees loose all detail as soon as you start moving. This is not simple motion blur. It is compression kicking in. Now imagine this on a big screen without the car moving but just the pan if you want to establish the scenery. It would be completely blurred...even if you would pan much slower than that. Just try again and post the result please. If you would compare that same pan with a the HDV Z7 it would be much better in terms of detail.
Best
Richard




http://www.richardladkani.com


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Steve Connor
Re: Sony EX1 Severe LongGop Problems
on May 25, 2008 at 9:37:56 pm

How are you viewing your footage Richard because I don't see the problem you are talking about in the posted clips.

Steve Connor
Adrenalin Television

Have you tried "Search Posts"? Enlightenment may be there.


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richard ladkani
Re: Sony EX1 Severe LongGop Problems
on May 26, 2008 at 7:23:01 am

I watched it on my mac. If you look at it single frame you will see the compression kicking in in the green grass, the wall and the leaves. Motion blur looks different.

Again on my test I compared six cameras side by side shot simultaneously with six camera operators. Only the EX1 performed strange on motion. The other cameras had simple motion blur only the EX1 went soft on detail whereas the others remained relatively sharp. Especially the Panasonics of course.
I will post some clips this afternoon for you all to see.
Best
Richard

http://www.richardladkani.com


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Chris Babbitt
Re: Sony EX1 Severe LongGop Problems
on May 25, 2008 at 5:18:09 pm

From what I understand, Richard, you are correct. It has to do with the long GOP compression. When shooting at the highest resolution on the EX, the resolution drops during pans. The reason you don't see it on the Z7 is because the resolution is already lower to begin with. I read this somewhere in this forum. Try doing a search for more info.



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Michael Palmer
Re: Sony EX1 Severe LongGop Problems
on May 25, 2008 at 5:28:08 pm

I'm not sure a $6500 camera is the right tool to make big screen projects, unless you can record at a lower compression level. That is where the Convergent Design's Flash XDR HD-SDI recorder comes in. With the XDR you control the compression level from HDV levels to completely uncompressed with future updates. It will offer 50 Mbps @ 4:2:2, 100 Mbps all i-frame 4:2:2 and up to 160 Mbps all i-frame 4:2:2 to begin with.
http://www.convergent-design.com/


I believe this will be the perfect solution to your projects and maximize the EX1 CMOS system.

Good Luck
Michael Palmer


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richard ladkani
Re: Sony EX1 Severe LongGop Problems
on May 25, 2008 at 5:56:04 pm

Hi there

The shutter was set to 1/50 of a second. It was identical on all other cameras.
By the way I was looking for a little brother for my main camera. I also tested a F900R an HDX900 and S16mm with the new Kodak Vision 3. The only camera with the LongGop Issue I described was the EX1. All other cameras performed well on pans and movement. The F900R won as the best camera for the main shoot. The little brother should have been the EX1 but with this LongGop blurry issues it will most likely have to be the Sony HVR-Z7. The HVX201 is also good but it only records 16min HD on a 16gb card which is too little. We have 80 shooting days.

Regarding the shoot with planes starting and landing... I cam not surprised you didn't have a problem as you moved the camera with the planes. If something moves with the camera it remains sharp. But if you pan across a landscape with alot of detail or something doesn't move with the camera but against it it becomes very visible.

Any more comments are welcome.

Thanx
Richard


http://www.richardladkani.com


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richard ladkani
Re: Sony EX1 Severe LongGop Problems
on May 25, 2008 at 6:21:32 pm

Hi Michael

Looked at this Compact Falsh Recorder. It looks interesting but I am not sure if it will solve the problem.
The question is when the LongGop Problem is generated? If it happens before the image is output over SDI then it's not a solution. If it indeed only happens when it's written to the SxS Card (which I doubt) then there is still two issues that are unpractical.

1. You are generating huge amounts of Data: 2,4 hours need 192gb of storage. An EX1 needs approx. 1/4 of that.

2. You need to feed Audio directly into the flash card which can become a cable nightmare when wanting to shoot "run'n gun" stuff.

3. It costs an additional 5000$

It might become interesting down the road but in the end it doesn't really help me with the issues described.

Best
Richard

http://www.richardladkani.com


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Michael Palmer
Re: Sony EX1 Severe LongGop Problems
on May 25, 2008 at 6:46:52 pm

The HD-SDI signal from the EX1 is before any compression. I'm sure the 50 Mbps setting would yield a superior image to the EX1 HQ record mode.

As to the run & gun, Convergent Design is working on a smaller second unit that will have only 2 cards that you can wear on your belt, it will also have HD-SDI & HDMI compatibilities for recording.

The price is a bargain for what you're getting, low cost compact flash cards and lower compression result in higher quality video. You can purchase 32 gig cards for $150 that will record 100 Mbps all i-frame 4:2:2. So now your into extremely high quality HD recording for an affordable price. No one is going to sell a full raster HD camera for under 14K that can produce what you can get from the EX1 XDR combo.

Good Luck
Michael Palmer


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richard ladkani
Re: Sony EX1 Severe LongGop Problems
on May 25, 2008 at 9:14:38 pm

Sounds interesting but let's get the focus back to the EX1.
I am looking for solutions to the problem without having to buy extra equipment. The EX1 is the most hyped camera these days. I would like to find out why nobody has talked about the LongGop Problem yet. It is so obvious others must see it too. If not then I would like to know why and how do they get around it...
Best
Richard Ladkani

http://www.richardladkani.com


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Steve Connor
Re: Sony EX1 Severe LongGop Problems
on May 25, 2008 at 9:41:42 pm

Or perhaps the few thousand owners of the EX1's that are out there aren't seeing this problem like you are. I'm sure if they had it would have come up before and it hasn't.

What detail level was the camera set to?




Steve Connor
Adrenalin Television

Have you tried "Search Posts"? Enlightenment may be there.


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Eli Hollander
Re: Sony EX1 Severe LongGop Problems
on May 25, 2008 at 10:11:51 pm

I have just taken my EX1 out to the backyard and filmed grass close-up, with different shutter speeds and different panning speeds.

At 1080 24p, at 48th of a second shutter speed, when panning, I did get a blur, which is expected (in fact, you want that blur to give the motion smoothness instead of a strobing quality), and at that shutter speed I didn't see any individual frames that were sharper than others (i.e., key frames).

At 1000th or 2000th of a second shutter speed, each frame was equally sharp and not blurred -- I couldn't replicate what you are describing. Each individual frame was sharp and there were no frames that looked sharper than other frames (key frames).

Admittedly I was looking at the images on my Mac screen, full frame (not projected using an HD projector). But, given what you describe, I would think that if the image were to be out of focus it would be noticeable on the Mac full screen.

It would be interesting if others were to try this experiment as well.

Eli



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richard ladkani
Re: Sony EX1 Severe LongGop Problems
on May 26, 2008 at 7:27:29 am

Hi Eli

Very interesting. I did the smae shots across grass and everything went soft even on the slightest motion. It didn't matter if I tried it in interlaced or 25p. I didn't try high shutterspeeds as I would never use it for regular shoots. People , motion, water looks completely unnatural in 1/1000 of a second.

Is there anyway you could post your pan across the grass on a site? In my opinion the blur is not motion blur but compression. You should be able to tell the difference when you pan really slow. If it goes soft even on very slow movement it's compression. I will post my shots this afternoon.

http://www.richardladkani.com


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Chris Babbitt
Re: Sony EX1 Severe LongGop Problems
on May 26, 2008 at 3:04:33 pm

Richard,

You are not crazy. Here is a link to a post on this forum from Jan 6 that explains it.
http://forums.creativecow.net/readpost/142/856569

I've seen this same issue on Discovery Channel, so it's not uncommon.



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richard ladkani
Re: Sony EX1 Severe LongGop Problems
on May 26, 2008 at 4:38:14 pm

Thanks Chris

I started thinking it's just me.It's a very good explanation of what I see. My uploads should bring some clarity into this discussion:)



http://www.richardladkani.com


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Eli Hollander
Re: Sony EX1 Severe LongGop Problems
on May 26, 2008 at 3:06:05 pm

I completely agree that 1000th sec shutter speed is not appropriate 99% of the time. But, for this test, a high shutter speed will tell you if the blur is motion blur or codec blur...

Maybe I wasn't looking at the right place, but at 1000th sec shutter speed I couldn't see any difference... and I couldn't see key-frames.

I already deleted these clips, but I'll shoot another test later today and post it.

Eli



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nick lantz
Re: Sony EX1 Severe LongGop Problems
on May 29, 2008 at 5:04:04 am

I may be chiming in a little late but I completely agree with Richard. I saw the problem immediately.
It was very obvious when panning across a crowd of people. Pretty much anytime you move the camera too quickly the image goes to mush. It is completely unusable when this happens. I shoot mostly hand held and I don't think i will be making the jump to this new camera. In defense of the EX it does look great when you move very slowly and I was very impressed with the colors and resolution.

Not to be mean but if you didn't notice this as a problem your just not looking with a critical eye. It is very obvious and something Sony will have to deal with at some point.

Nick Lantz
nlantz2005@yahoo.com



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richard ladkani
Re: Sony EX1 Severe LongGop Problems
on May 29, 2008 at 7:07:04 am

HI Nick

have you read my last comment on the thread EX1 vs. Z7
I noticed that my shutter was set to 1/25 or set to OFF in 25p mode.
Did you try it with the shutter on?
It looks much better.

http://www.richardladkani.com


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Annaël Beauchemin
Re: Sony EX1 Severe LongGop Problems
on May 26, 2008 at 6:13:25 am

I work with footage mainly shot with the EX1 and I do see what you are talking about. But I thought it had to do with the CMOS chip, not the Long GOP MPEG2. Along the same lines with the problem it has with photo flashes.

The problem not only on the resulting pictures, but when shooting... if you put Peaking on to get you focus right, it's pretty hard to see the peaking edges when the subject is moving because of the blur. My thinking was that it's a CMOS effect since the LCD is probably shoing the raw (uncompressed) output of the CMOS.




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richard ladkani
Re: Sony EX1 Severe LongGop Problems
on May 26, 2008 at 3:42:12 pm

I am currently uploading about 12 shots where you can all compare the EX1 and the Z7 in their original quality. You should download the quicktimes as source files.
As soon as it's uploaded I will post the link. You will need good broadband though. Total diskspace of the site is almost 800mb.
Best
Richard



http://www.richardladkani.com


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Bruce Rawlings
Re: Sony EX1 Severe LongGop Problems
on May 26, 2008 at 4:12:08 pm

Just a thought but have you tried looking at your pictures on a CRT monitor? I see the effect you are describing on everything that is shown on my LCD 32" Panasonic screen.





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richard ladkani
Re: Sony EX1 Severe LongGop Problems
on May 26, 2008 at 4:20:35 pm

Yes I checked my 14" CRT monitor.
Same issues.

http://www.richardladkani.com


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Steve Brown
Re: Sony EX1 Severe LongGop Problems
on May 26, 2008 at 5:03:40 pm

Hi Richard,

I'm not sure about your major issue, although I do agree it is probably caused by compression. The compression should be bypassed by going HD-SDI out. It would be unusual for compression to be applied to that output.

I looked at the Flash XDR at NAB and I was very impressed... I'm probably a buyer when they are actually available as it is the perfect solution for me. I have two HDX900s, which record on tape only (DVC-Pro100). That system will accept audio and time code in the SDI stream, as most systems do. Of course, you'll have to check to be certain the EX-1 actually provides those signals in the SDI stream.

The Flash XDR actually starts recording when it senses incrementing time code, unless you are using the Firewire connection. And FYI... using the Firewire connection would not be recommended if you're trying to get past the compression issues.

I'll forward this link to a friend of mine who has an EX-1 and ask him for his $.02. Maybe he can contribute, as well.

Steve Brown
10-20 Productions


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Steve Connor
Re: Sony EX1 Severe LongGop Problems
on May 26, 2008 at 5:11:41 pm

If the detail level on the camera is set very high you can get this effect - I can even get it if I crank the detail level up on our HDW750 on HDCam, with the detail at a reasonable level I am just not seeing any more problems in panning than on our 750.

Steve Connor
Adrenalin Television

Have you tried "Search Posts"? Enlightenment may be there.


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richard ladkani
Re: Sony EX1 Severe LongGop Problems
on May 26, 2008 at 5:49:43 pm

ok finally the uploads have completed. Now let's talk about what we see here.

Please check this link

http://www.richardladkani.com/cameratest_main/cameratest/index.html

You will find about 10 shots aswell as screenshots taken from the same footage.
you will have to download the quicktimes as source to see it in its original quality and full screen. Just click download on the detail page of the movieclip.

Let's see what you have to say to these clips.

All the best
Richard

http://www.richardladkani.com


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jim brodie
Re: Sony EX1 Severe LongGop Problems
on May 26, 2008 at 8:54:37 pm

Did you find the same problems when set to 1080i or 720i, because when I encountered these problems with very detailed shots involving pans this seemed to solve the issue?

Cheers,

Jim



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richard ladkani
Re: Sony EX1 Severe LongGop Problems
on May 27, 2008 at 6:52:35 am

Yes I had the same results in 1080i
Made no difference at all.

http://www.richardladkani.com


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Mick Haensler
Re: Sony EX1 Severe LongGop Problems
on May 27, 2008 at 1:16:19 pm

Hi Richard

QT is prompting me to download some 3rd party software. Would you know what that would be? Otherwise I all I get is audio and a white screen. Thanks

Mick Haensler
Higher Ground Media



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richard ladkani
Re: Sony EX1 Severe LongGop Problems
on May 27, 2008 at 3:21:22 pm

Hi there

I don't know what that could be. Maybe it has something todo with the fact that both are very new codecs and might require a special plugin from sony. I only installed the clipbrowser from sony but I don't know if this has something to do with the plugin.
Make sure you have the latest quicktime though.
Good luck
Richard

http://www.richardladkani.com


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Ron Shook
Re: Sony EX1 Severe LongGop Problems
on May 27, 2008 at 5:30:27 pm

Mike,

[Mick Haensler] "QT is prompting me to download some 3rd party software. Would you know what that would be? Otherwise I all I get is audio and a white screen."

Same with me. Doncha just love it?

Ron Shook
Shoulder-High Eye Productions
CreativeCOW Forum Host for Discreet edit*


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David Bispham
Re: Sony EX1 Severe LongGop Problems
on May 27, 2008 at 10:14:26 pm

I could play the first couple of clips and save it to my hardrve on a MAC that has FCPro and the necessary software to view XDCAM footage, then one clip just partially downloaded and played and I assume the other images were just stills. On the PC it is audio with a white screen. I don’t really need to see the footage because I know this blur you are talking about.

With my Ex 1 footage I have noticed lots of artifacting, blurring, noise, whatever you want to call it with pans and zooms, or objects moving somewhat rapidly while camera is stationary. As soon as camera is still it makes a beautiful image. If I track the moving object the image is good and I find the artifacting is less at 60p than 30p and that would be 720. My shutter switch is off.
I also find beautiful imagery with over crank and under crank.




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Bo Skelmose
Re: Sony EX1 Severe LongGop Problems
on May 28, 2008 at 11:31:27 pm

Hi
Maybe this could be an issue on the editing software - maybe some software/editing hardware are able to generate the right pictures from the long gop in the timeline and some are not. That could be the explanation why some have sharp pictures at every eight pictures and someone else do not have that problem ? just a thougt...



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David Bispham
Re: Sony EX1 Severe LongGop Problems
on May 29, 2008 at 4:11:17 pm

I view the footage on a Sony LMD-2050W played off the SxS card from the camera, so an edit system would not be the case in my situation.
As you can see in the above threads the problem should be resolved by changing the shutter speed. I am hesitant to do this because of the rolling shutter issue, so I figure If I stick with 720p 60 I should be OK, although I will continue to test this.




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Mike Schell
Re: Sony EX1 Severe LongGop Problems
on May 29, 2008 at 6:38:56 pm

Hi Richard-
The absolute definite way to evaluate this problem would be to record uncompressed video out the HD-SDI port and compare this result (on a frame by frame basis) to the video stored on your SxS cards. Then you can determine if the artifacts and blurring is caused by the compression or some other setting, such as shutter speed. (I suspect compression issues).

Long-GOP MPEG2 compression generally performs well, even with some motion. However, there are some situations where Long-GOP will fall short, especially in highly complex images, such as grass. MPEG2 P and B frames are created by comparing the current frame to the I frame and then compressing the difference. If subsequent frames within a GOP are radically different than the original I Frame, then this differencing approach can create artifacts.

So, in high-complex, high-motion situations, I-Frame only, will likely produce better results. Our Flash XDR portable recorder gives you this option. You can record in full-raster (1920x1080) Long-GOP 4:2:2 at 50 or 100 Mbps rates for most applications. This produces excellent video quality for most applications and is the most space efficient (longer record times).

But for the really complex moving images, you can select MPEG2 I-Frame only full-raster 4:2:2 recording at 100 or 160 Mbps rate. This mode would eliminate any of the motion artifacts caused by the temporal compression used in Long-GOP.

Flash XDR gives you the option to dial in the compression bit-rate and type of compression to match the situation. You can even record different bit-rates and Long-GOP / I-Frame only to the same Compact Flash card and then upload to your NLE.

Mike Schell
Convergent Design


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Steve Brown
Re: Sony EX1 Severe LongGop Problems
on May 30, 2008 at 11:52:37 pm

Hey Mike,

As you could probably tell from my post above, I'm a fan of the Flash XDR. When will it actually start shipping? And what about the Nano Flash? I use Panasonic HDX900s, so I don't have the Long GOP issues, but there are some issues with DVC-ProHD too. I'd love to be able to by-pass that.

Steve Brown
10-20 Productions


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Amit Virmani
Re: Sony EX1 Severe LongGop Problems
on Aug 14, 2008 at 9:15:17 am

Hi. I just bought the EX1. I've found a major problem on all my test footage. Any camera movement results in jumpy footage. At first I thought it was my cheap tripod, but today I tried zooming in and out on an otherwise locked shot. Same problem. After every couple of seconds there's a jump, as if the picture is catchng up to where the camera is then.

Am I missing something, or should I ask Sony to fix something?

Thanks in advance!

P.S. The camera has the 1.05 firmware.


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richard ladkani
Re: Sony EX1 Severe LongGop Problems
on Aug 14, 2008 at 11:50:39 am

Hi

I am pretty sure you are playing your footage back on a computer when you see the jumps, correct? If that is the case than your computer cannot play back Full HD in real time or doesn't have the codec installed properly. Try playing back the footage on your camera and see if you get the same jumps. If yes then there is a problem with your camera if not it's your computer.
Good luck
Richard



http://www.richardladkani.com


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Amit Virmani
Re: Sony EX1 Severe LongGop Problems
on Aug 14, 2008 at 2:04:03 pm

Thanks Richard. So glad you suspect that cos it just occurred to me somewhere in between the panic attacks too. I got a new MacbookPro, 2.5GHz / 2GB RAM, so I just took Full HD playback for granted. Is 4GB is the recommended RAM?

Played back some of the footage on the camera. From what I can tell it's ok. But I'm going to hook up the cam to a friend's Plasma screen tomorrow just to be sure. I'm a bit paranoid, the LCD screen being small and all.

Thanks again!



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Charles Taylor
Re: Sony EX1 Severe LongGop Problems
on Aug 21, 2008 at 10:19:30 pm

Much more motion blur on the EX1 shot you posted. Looks better to me than the Z7 shot, but horses for courses.

Couldn't see the 8 frame pattern you mentioned, would it be possible for you to name a couple of sharp frames?



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richard ladkani
Re: Sony EX1 Severe LongGop Problems
on Aug 22, 2008 at 9:17:05 am

The motion blur was due to the fact that the shutter was turned OFF. When on later tests the shutter was ON at 1/50th of a second everything was fine.
Best
Richard


http://www.richardladkani.com


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Steve Brown
Re: Sony EX1 Severe LongGop Problems
on Aug 23, 2008 at 10:26:15 pm

Hey guys,

I wonder if someone can clarify this for me. I was considering buying an EX-1 or an EX-3 for use as a POV camera, but this business of motion artifacts due to long GOP scares me a bit. Do you mean you have to use a particular shutter speed to avoid these artifacts? In my world, shutter speeds are not used for that purpose and I'd hate to have to use a 1/50th when I want 1/30th, 1/48th or 1/60th, etc.

Am I missing something here?

Steve Brown
10-20 Productions


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Craig Seeman
Re: Sony EX1 Severe LongGop Problems
on Aug 23, 2008 at 10:37:48 pm

There are no motion artifacts that I've ever seen with 35mbps VBR XDCAM codec. It's very hard codec to break. I've shot rippling water, leaves blowing in the wind, fireworks, tennis players, all look great. Don't believe misinformation.

In some cases there can be rolling shutter on camera flashes. You can get "bending" if tracking a fast moving object with a very fast pan due to CMOS chip scan. I don't find that a problem and neither do my clients. CMOS has pluses and minuses just as CCD chips do.



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Steve Brown
Re: Sony EX1 Severe LongGop Problems
on Aug 23, 2008 at 11:02:24 pm

Craig,

Are you referring to the XDCam, XDCam HD or XDCam EX? I have never heard of this problem with XDCam or XDCam HD, but I seem to be hearing a lot about this problem with the EX versions of XDCam. From what I am hearing, it sounds as though the problem is the internal long GOP recording process - similar to motion artifacts seen with HDV.

Keep in mind, I have not seen this problem with the Sony EX cameras. I have only seen those cameras a couple of times and there was not enough motion to be a problem in either case. I have seen the problem with JVC 250 cameras, however... and I understand that this problem is essentially expected in the HDV format.

Someone please set me straight if this is not correct!

Steve Brown
10-20 Productions


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Craig Seeman
Re: Sony EX1 Severe LongGop Problems
on Aug 24, 2008 at 12:10:42 am

[Steve Brown] "Someone please set me straight if this is not correct!"

Not correct. I own an EX1 and I've shot many things that would cause HDV to crumble. EX is an XDCAM camera using the same 35mbps VBR codec. It's wrapped in MP4 instead of MXF but that's just a wrapper, not the codec.

Personally I think a lot of people who use EX series who make such claims are wrongly identifying other issues as codec issues. Rippling water and blowing leaves are about the toughest thing you can throw at a GOP codec and that doesn't even have a hint of breaking. In fact I think many people don't even understand what "motion" is to a codec. Rippling water is constant and rapid change from frame to frame and can be across the entire frame depending on framing. Motion does NOT have to be spinning the camera around.



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Steve Brown
Re: Sony EX1 Severe LongGop Problems
on Aug 24, 2008 at 4:50:17 pm

Craig,

Thanks for the info. I guess I need to see the camera myself and use it enough to see if problems I've heard about have any validity. I have seen some problems with the HDX900s also and careful adjustment of detail coring has helped tremendously with things like trees with blowing leaves and other high detail subjects.

Do the EX series cameras have adjustment for "detail coring" and "level depend"?

Steve Brown
10-20 Productions


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Andrea Chung
Re: Sony EX1 Severe LongGop Problems
on Sep 29, 2008 at 12:05:56 am

excerpt from Wikipedia that explains it re: rolling shutters:

As opposed to a global shutter, where the whole of the sensor is presented with light at once, resulting in the whole of the frame being captured simultaneously, with a rolling shutter, the image is captured sequentially in thin rows from top to bottom, one after the other, over the course of a single frame.

Rolling shutters have the potential to frustrate videographers by creating rolling shutter "artifacts" due to the possibility of the camera moving during the time when the top and bottom of a single frame are captured. This can result in issues such as "skew", "partial exposure" and what is colloquially known as the "Jellocam" phenomenon.

& this article:

http://dvxuser.com/jason/CMOS-CCD/


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Sean McPhillips
Re: Sony EX1 Severe LongGop Problems
on Oct 13, 2008 at 12:11:06 pm

'The motion blur was due to the fact that the shutter was turned OFF. When on later tests the shutter was ON at 1/50th of a second everything was fine.
Best
Richard'


So, does this solve the original problem then?

Just wondering.

If so, can we have a reference to it at THE TOP of this thread FCOL?

Thanks ;~)

Sean McPhillips


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Steve Brown
Re: Sony EX1 Severe LongGop Problems
on Oct 13, 2008 at 3:40:36 pm

OK, so here is the problem I am having with all of this. Does this mean that one is forced to shoot with a particular shutter speed in order to avoid these problems? That seems a little crazy to me. If I'm shooting at 24 fps (progressive), I generally have a 180 degree shutter angle equivalent to 48 fps. If I'm shooting at 30 fps (progressive), I do the same thing, so my equivalent shutter speed will be 60 fps. (OK, in reality the frame rates are fractional... but they are close to those rounded numbers - actual frame rates would be 23.976/47.952 and 29.97/59.94.)

I wouldn't want to be forced to shoot at a shutter speed of 1/50th (or any specific frame rate) just to avoid artifacts. And what if I want to shoot for slo-mo? Normally, I'd shoot at 60 fps (progressive) with or without a 180 degree shutter angle. Is that going to be a problem also? Or will that faster shutter speed help to alleviate the problem as well?

Feel free to set me straight if I am misinterpreting any of this. These little quirks are why I have stayed away from the smaller cameras in the past, but I'd sure like to have a quality HD camera to carry on hiking trips, kayaking trips or other adventures where a full sized HD camera just isn't practical.

Steve Brown
10-20 Productions


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richard ladkani
Re: Sony EX1 Severe LongGop Problems
on Oct 13, 2008 at 2:51:24 pm

Hi,

I was asked to clarify this thread at the top.

The problem has been solved. There is no Long Gop Issue or motion blur problem. The shutter of the camera was turned OFF which means it was at 1/25th. When turned on to 1/50th all problems are solved. Fact is: YOu have to turn on the shutter manually when shooting 25p! Very important.

Best wishes
Richard

http://www.richardladkani.com


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