View Full Version : Strobing / flicker effect when panning in 24p


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Steve Phillipps
May 27th, 2008, 08:15 AM
Well Dennis, that pretty much sums up what I think too.
Thing is Alister, when you say "I don't understand why anyone expects there not to be judder or stutter when you are doing pans while shooting at 24 or 25P with a 1/50th shutter", the answer is because you don't see it with other cameras. You see blurring yes (kinda gives you a nostalgic feeling for interlaced really!), but not stuttering. That's the difference that I was pointing out.
Also I think it's a bit odd to say that "EX1 material must be some of the simplest material in the world to get off the camera and convert", after all the reason I can't post it is that I can't get the bloody shots into mpeg or some form that I can post! Unlike many here I don't do my own editing, call me old fashioned but that's not my job, I just shoot the pictures.
I can put images onto my Macbook and convert them to mpeg4 from Panasonic HPX2100, HPX500, Canon XL, even Phantom HD, but couldn't do it from EX1!
Steve

Craig Seeman
May 27th, 2008, 08:24 AM
Steve, I can at least make a suggestion to give you the ability to make your files generally viewable.

http://ffmpegX.com/download.html

The above shareware utility can take the EX1 MP4 and encode them to a variety of formats (H264 for example) that you can upload or otherwise view and share.

Steve Phillipps
May 27th, 2008, 09:03 AM
Thanks Craig, unfortunately I've deleted my test files, didn't think I had any further use for them.
Steve

Steve Connor
May 27th, 2008, 09:11 AM
Allister, thank you for that footage.
I refused to believe that 35mm film 24p is the same as video.

This I will agree with, IMHO ANY video 24 or 25P is not the same as film - it's a close approximation but the motion still looks different but that's true of all video cameras.

However compared other video cameras I see no difference in the EX1 progressive footage.

Dave Elston
May 27th, 2008, 10:02 AM
Hi All,

Not wishing to add more noise to this already weighty thread, I simply want to suggest the following 'acid' test...

Dominik Seibold posted a few grabs and merged frames a few days ago which were taken from his EX1 on a spinning chair.

My idea is for a similar repeateable test, but instead place a mirror on the chair (or even better a turntable) with a distant point source light - now you can point two or more different cameras at the mirror and hit record to see how motion is rendered by the different hardware as the reflected light source passes across the frame.

I was a little confused why Dominik chose a shutter angle of 11.25° in his test (=1/768 shutter speed !?) but accept that that was his choice for whatever reason.
I have faked a 'normal' 180° motion blur (added crudely in photoshop) on his merged frames and would expect a very similar result to this from any progressive camera...

Anyone have the inclination (and access to a variety of cameras) to do this would help to settle this issue/thread pretty quickly IMO.

Just my 2p ;)

Cheers,
Dave.

Dominik Seibold
May 27th, 2008, 11:08 AM
I was a little confused why Dominik chose a shutter angle of 11.25° in his test (=1/768 shutter speed !?)
I can't remember exactly why I choose that narrow angle. Perhaps I wanted sharper spots, but of course the result with 180° is more important.
For blending pictures together I wrote a little java-app:
http://www.dominik.ws/PictureAverager.jar (just double-click for launching)
and the source-code:
http://www.dominik.ws/PictureAverager.java
It makes an average-picture out of all pictures in a given folder.
It works like this:
1. Choose the folder with the pictures (all java supported formats like png, jpeg, gif,...). Of course they all must have the same dimensions.
2. Choose the output-filename. The output will be saved as 32bit-png.
3. choose whether to normalize the result or to get the true average.
4. press start
It solely uses integer-arithmetic. First it sums all the channelPixels. Then the per channelPixel result is calculated with the formula sum/pictureCount or with normalization turned on 255*sum/maxSum where maxSum is max(max(red pixels), max(green pixels), max(blue pixels)).

Alister Chapman
May 27th, 2008, 11:46 AM
Sony EX1 and JVC HD 101 side by side comparison. Slow and fast pan 25p 1/50th second.

http://www.ingenioustv.com/clips/ex1-hd101-motion-test.mov

Paul Curtis
May 27th, 2008, 12:02 PM
Sony EX1 and JVC HD 101 side by side comparison. Slow and fast pan 25p 1/50th second.

http://www.ingenioustv.com/clips/ex1-hd101-motion-test.mov

Thank you Alister, they look pretty damn identical to me, even single stepping through it (aside from the rolling shutter obviously)

I don't want to be seen laboring the point but i wouldn't want others reading this thread to assume it was a problem (or at least a general problem with the EX)

cheers
paul

Steve Phillipps
May 27th, 2008, 12:31 PM
Thanks once again Alister for taking the time to do this. Yet again, they look the same to me (ie both jerky!) certainly neither camera has an obvious "problem" compared to the other.
Out of interest, I'd say "D" was the EX1, just has that less video look to it (a plus point!). Am I right?
Agree with you Paul, I've said the same above more than once, that people should not "assume" there is a problem here, just be aware that some folks have flagged it and bear it in mind when doing your own tests.
Steve

Alister Chapman
May 27th, 2008, 12:38 PM
Yes D is the EX1.

I have not used my HD101 for some time and it was certainly interesting to see the two side by side on a big HD monitor.

Steve Phillipps
May 27th, 2008, 12:54 PM
I will stick my neck out and say that I do think that the picture quality from the EX1 is quite possibly the nicest I've seen from any video camera. Ever!
It's so much more similar to what you get from a DSLR, very smooth and slightly muted, not "electronic-looking" at all. When I had the camera I put in BBC-like flat settings to get the best DR, exported a still into Photoshop and did some basic manipulation to simulate a grade, and the pic looked gorgeous.
Steve

Dominik Seibold
May 27th, 2008, 01:01 PM
The clipped areas of the jvc are looking very ugly. Is that normal? Also it has less detail, but a lot of that video-style-sharpening at lower frequencies, a narrow dynamic range and a lot of ca.
The ex1 looks like I love it: wide dynamic range, sharp, clear and natural.

Chris Hurd
May 27th, 2008, 01:09 PM
Just a warning here from a housekeeping perspective: I have removed some posts from public view that are pretty much just borderline flaming -- pretty soon now I'm going to start locking accounts. Some of you guys really need to knock it off. You know who you are. It's only a matter of time until I kill this thread...

Steve Connor
May 27th, 2008, 01:11 PM
Also worth mentioning that the other problem reported on DVX User mentioned earlier in this thread looks to be confirmed that the operator was shooting with no shutter on!

Can we just conclude that the EX1 performs in progressive mode like any other video camera and that progressive video doesn't quite have the nice motion that film has - then we can move on :)

Alister Chapman
May 27th, 2008, 02:14 PM
To be fair on the HD101 it was probably bordering on being over exposed. Lots more quite harsh enhancement from the JVC but then it was running the stock factory setup while the Ex1 was running my preferred profile which has much reduced detail enhancement.

Robert St-Onge
May 27th, 2008, 03:34 PM
Just an update, I was one of them thinking the EX1 had more judders but I must admit after doing a quick side by side comparison off a Panasonic HVX2000 (not the 200) and the EX1 at 24p that both showed equal amounts of judders. I was shooting cars driving by at about 50 kms and was very happy to see that a much more expensive camera with ccd's as opposed to cmos and rolling shutter showed the same effect.
So yes, you must adapt your shooting techniques to 24p recording. I noticed that if you are to get a static shot of a car going by, it's doesn't look great, but if you precisely pan as the car goes by, what a difference, it felt very cinematic!

David Hadden
May 28th, 2008, 05:32 PM
So yes, you must adapt your shooting techniques to 24p recording. I noticed that if you are to get a static shot of a car going by, it's doesn't look great, but if you precisely pan as the car goes by, what a difference, it felt very cinematic!

After having read these posts and posts and posts about 24p juddery, and how the EX-1 has more judders etc... I just kept saying in my head, don't these people know that you can't shoot 24p the same as 60i or 60p??? When it's all said and done, it would appear that this is the case. I've long known that there are restrictions with the way one shoots 24p vs. the standard 60i (starting out on DVX's you learn this to be the case early on). I have to say too, I know it's maybe a little lame, but there's just something pleasing to me, when I see 24p over 60i. I shoot most everything I can in 24p, and I'm pleased to know that my next camera will be able to perform it so aptly.

Dave

Chris Hurd
May 28th, 2008, 06:21 PM
There is nothing wrong with the way the EX1 captures motion. There are thousands of EX1's in daily use, yet there are less than a dozen (very vocal) people claiming that there is some kind of fault. There are even fewer examples of this "problem" being posted as clips. I think what we are seeing is people getting a camera that can shoot true progressive with a level of detail and resolution that really shows up the issues you get with shooting progressive at low frame rates. Then in many cases the material is being viewed on computers or monitors that add further issues and inconsistencies. This is then being viewed by people not used to seeing such images that don't understand the very nature of progressive and whole frame capture by video and film cameras."There is nothing wrong with the way the EX1 captures motion."

I can't think of a better way to conclude this thread.

Thanks Alister,