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Old February 28th, 2016, 06:02 PM   #1
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slow motion specular highlight issue

I could really use some help here, I am having issues with specular highlights in my 240fps slow-motion. dancing/moving purple block like artifacts around the specular highlights.

Please watch the youtube video in 1080 and let me know if you guys have encountered the same thing, I have contacted Sony but would really help me to know if I have a camera with an issue or its just the way it is.

https://www.youtube.com/watch?v=Myj7...ature=youtu.be
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Old February 28th, 2016, 08:47 PM   #2
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Re: slow motion specular highlight issue

That's... interesting. Not sure what to make of it. Looks like macroblocking, but isn't. Looks like a math error, but could be anything from the sensor on down the video chain.

Reminds me of a math error I found in a raster image processor (RIP) about 12 years ago. When something was fully white (r=b=g=256) the software would experience a rounding error and would wrap those pixels back around to fully black (r=b=g=0). Nothing like a black sun or a black light bulb to make a photograph look nicely surrealistic. ;-)

But this is effecting pixels well outside the specular highlights. So it looks more like a compression error. Like you, I'd be asking Sony about this.
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Old February 28th, 2016, 11:02 PM   #3
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Re: slow motion specular highlight issue

i have the same problem...second 1:16



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Old February 29th, 2016, 01:13 AM   #4
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Re: slow motion specular highlight issue

Quote:
Originally Posted by Bruce Watson View Post
That's... interesting. Not sure what to make of it. Looks like macroblocking, but isn't. Looks like a math error, but could be anything from the sensor on down the video chain.

Reminds me of a math error I found in a raster image processor (RIP) about 12 years ago. When something was fully white (r=b=g=256) the software would experience a rounding error and would wrap those pixels back around to fully black (r=b=g=0). Nothing like a black sun or a black light bulb to make a photograph look nicely surrealistic. ;-)

But this is effecting pixels well outside the specular highlights. So it looks more like a compression error. Like you, I'd be asking Sony about this.
I like your term "math error" that seems to jive with what I thought it looks like... a digital looking problem or like code issues or something....on FB a few people questioned the lenses but I can easily replicate it with a 400mm 2.8, 200-400 f4 plus Metabones, Sony 18-55 and Sony 50 1.8 and that would not account for that sharp random blinking look

FYI Where I also posted this on the FS5 FaceBook I was surprised that someone posted identical issues with the FS700 so it may just be life with super slow motion and the need to shrink it fast (it does line skipping or something for sure)

I sent the original footage to Sony, I will post what they tell me

thanks
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Old May 10th, 2016, 12:25 AM   #5
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Re: slow motion specular highlight issue

Did you end up getting a reply from Sony on this? I'm having the same issue.
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Old May 11th, 2016, 09:35 AM   #6
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Re: slow motion specular highlight issue

"Hi Ray,



Sorry to report, what you are seeing is the limitation of the camera at HFR.

According to test performed, using 120fps will reduce the symptom.

Also, reducing the contrast of the move will also improve, although it may be difficult to control.


Welcome back for any comment you may have."

after over a month of me emailing I got the statement above.... basically they didn't bother to look at my sample video and just gave the generic answer about slow motion in general. I know its not going to be as good as regular HD but it should not have dancing purple blocks and lines around the specular highlights...FYI 120 is exactly the same as 240 :( For some its not a big deal but I shoot motorsports so slow motion is a big deal and specular highlights on cars and motorcycles are in EVERY shot.... I can't use the FS5 sow motion for work and am now in the process of picking up a used FS700

I am not after perfection even if Sony could eliminate the color part of the issue I could work with it... but the flickering color its just nuts. Even "regular" people pointed it out, not just camera geeks like me :(
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Old May 12th, 2016, 04:46 AM   #7
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Re: slow motion specular highlight issue

Yep, Sony are marketing this as a professional camera with super slow motion capabilities, but a high percentage of the slow motion footage I've shot with it wouldn't be acceptable in a professional production.

I would have purchased the FS7 if I'd known about this issue before I bought the camera. It's almost a deal breaker.

At risk of being blunt; words like 'false advertising' come to mind.
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Old May 12th, 2016, 05:51 AM   #8
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Re: slow motion specular highlight issue

Quote:
Originally Posted by Jody Arnott View Post
Yep, Sony are marketing this as a professional camera with super slow motion capabilities, but a high percentage of the slow motion footage I've shot with it wouldn't be acceptable in a professional production.

I would have purchased the FS7 if I'd known about this issue before I bought the camera. It's almost a deal breaker.

At risk of being blunt; words like 'false advertising' come to mind.
It is possible to get some very nice results in SloMo with the FS5. All cameras have some problems. I would be tempted to try a ProMist filter on high contrast Slomo. If I get a chance I will try this out soon.

I remember in the past CCD cams had really bad problems with vertical smears on bright lights.Unfortunatly we have to find the limitations of our gear and use it accordingly. My point is, SloMo is not perfect but compared to having none it is very nice.

Here is a sample shot at 240 and then slowed down to 480 using optical flow in FCPX. Bear in mind that Vimeo compresses pretty heavily.

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Old May 12th, 2016, 08:35 PM   #9
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Re: slow motion specular highlight issue

Its not just "problems" I sent samples in and were all rejected.. pro sports but not anything nearing the popularity of NFL, NHL or NBA... not even close yet rejected for online use. Bidding on a used FS700 as I type this :(

a little soft is ok, some jaggies completely understandable... dancing purple blocks and lines that don't show on a 5 year older cam or a the new sony pocket cam at 1/5 the price.... thats a real issue.

It looks like the same type of ripping that the original UHD had only in vibrant color and some extra blocks thrown in for good measure.
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Old May 12th, 2016, 08:38 PM   #10
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Re: slow motion specular highlight issue

Quote:
Originally Posted by Jody Arnott View Post
Yep, Sony are marketing this as a professional camera with super slow motion capabilities, but a high percentage of the slow motion footage I've shot with it wouldn't be acceptable in a professional production.

I would have purchased the FS7 if I'd known about this issue before I bought the camera. It's almost a deal breaker.

At risk of being blunt; words like 'false advertising' come to mind.
I have the FS7 as well... it doesn't have this issue but keep in mind its a fair amount larger... large enough my portable slider and my gimbal wont work with it, plus the media is more. Better codec and I think a better value than the FS5 but the extra costs do stack up pretty quickly. Oh and man do I miss that fs5 ND when I use the 7!!
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