abrupt highlights clipping

Leonard Levy · February 5th, 2008, 11:53 AM

Maybe I'm over-reacting here - and my head did tend to gloss over some of the technical analysis - but i still find myself disturbed taht an ordinary setting on the EX-1 would do this.

I'm not comparingm it to V1's or any other 1/2" "semi-professional" cameras , but rather to run of the mill 2/3" professional Sony & Ikegami cameras taht I've been using for many many years. You should be able to shoot decent looking pictures in standard gamma without being terrified that if you overexpose your sky the picture will start artifacting. To me its completely unacceptable.

Now I don't ever recall seeing this with any semi-pro video camera either like an DVX100 or an HVX200 or even a PD100 for that matter.

It sounds like the only thing you did unusual was add some saturation to the matrix - is that right?

Am I over-reacting here? I mean this is a totally ordinary shooting situation.

Maybe you are right that you need to avoid the standard gammas. - that would be a drag. Did you try anything other than STD 3?

Piotr Wozniacki · February 5th, 2008, 12:04 PM

Quote:

Originally Posted by Leonard Levy

Maybe I'm over-reacting here - and my head did tend to gloss over some of the technical analysis - but i still find myself disturbed taht an ordinary setting on the EX-1 would do this.

I'm not comparingm it to V1's or any other 1/2" "semi-professional" cameras , but rather to run of the mill 2/3" professional Sony & Ikegami cameras taht I've been using for many many years. You should be able to shoot decent looking pictures in standard gamma without being terrified that if you overexpose your sky the picture will start artifacting. To me its completely unacceptable.

Now I don't ever recall seeing this with any semi-pro video camera either like an DVX100 or an HVX200 or even a PD100 for that matter.

It sounds like the only thing you did unusual was add some saturation to the matrix - is that right?

Am I over-reacting here? I mean this is a totally ordinary shooting situation.

Maybe you are right that you need to avoid the standard gammas. - that would be a drag. Did you try anything other than STD 3?

Leonard, you certainly are not over-reacting; my opinion is the same as yours and this is why I started this thread, and even added a suggestion on improving the algorithm behind it in the firmware update wish thread.

And no - apart from adding some saturation and slightly lowering blacks, I didn't do anything else to the most standard factory settings (it's exactly the Bill Raven's PP which he says he arrived at as the most neutral and natural colour setting, using WFM and things :))

Leonard Levy · February 5th, 2008, 12:05 PM

Thanks for posting this Poitr and i will do some test myself.
I haven't really tested this camera very carefully just assumed that ordinary circuits like this would work properly.

As I mentioned I have seen sony send out misadjusted auto knee circuits on top end $50,000 cameras in the past so I'm hoping that's all it is.

Steven Thomas · February 5th, 2008, 12:33 PM

Well, there's no doubt that it does look odd with your std gamma examples. I'll have to try to recreate this problem. I guess I have not seen it, since I mainly use cine curves.

Bill Ravens · February 5th, 2008, 12:37 PM

Piotr...

Your image41 is not the same one that I saw that was very overexposed. Image41 definitely looks very strange...actually, it looks like the white balance settings are off.

Piotr Wozniacki · February 5th, 2008, 01:04 PM

Quote:

Originally Posted by Bill Ravens

Piotr...

Your image41 is not the same one that I saw that was very overexposed. Image41 definitely looks very strange...actually, it looks like the white balance settings are off.

Bill,

The image41 comes from the very same few seconds of shooting; it's actually a couple of frames away from those previously posted. I made the reservation about WB not being right in my original post.

The only difference between image41 and the previous four is that this one has been grabbed from an 8bit Vegas project, while the previous ones - from a one with 32bit video setting.

Do you agree now that it's not the question of overexposing, but of how being on the verge of overexposing is being handled by the EX1? I guess it'd be very important for all of us users if all the interested parties came to a conclusion, as it could be passed on to Sony as an important issue for the future firmware release.

Bill Ravens · February 5th, 2008, 02:10 PM

Piotr...

when you switched to 32-bit processing, did you check the Vegas WFM for clipping? Ordinarily, when I switch between 8-bit and 32-bit, I need to apply a correction, depending on the codec type. One can't arbitrarily turn on 32 bit without adjusting levels.

For example, .mxf files, I can drop a native .mxf file on the timeline in 8-bit and the levels look right, black is at IRE16 and white is at IRE235. If I switch to 32 bit, suddenly black is at 0(-8% IRE) and white is at 255 (108% IRE) These values are techncally blown out if you're looking at a studio RGB monitor. A Level correction converting computer RGB to studio RGB is needed to correct the images.

Piotr Wozniacki · February 5th, 2008, 02:38 PM

Bill,

Yes I am aware of how mfx decodes in 8bit vs 32bit Vegas projects, and belive me this is not the source of the problem. With 32bit, applying the Computer RGB to Studio RGB convertion is barely visible; in 8bit the difference is more apparent (right half of the grab below is converted to Studio RGB; while the superwhites are remapped, the blue "shadow" behind the trees is still there).

But believe me, Vegas is not the factor; in fact I only use it take grabs from timeline. The problem is clearly visible by just playing the file with WMP.

Bill Ravens · February 5th, 2008, 02:53 PM

Guess I'm with Steve Thomas. Other than my initial foray into STD curves, which I abandoned very quickly, I don't use them much. I'll look at this some more to see if I can make my cam malfunction like this. In CINE mode, all the manual knee adjustments are disabled. In STD mode, auto knee is turned on. I'm not sure how this functions. Could it be that the camera processor pushed the knee out to an irrational setting to cause what you're seeing?

I must say that I just finished shooting a 240 sec short ...lots of gray skies, snow everywhere, a few patches of blue here and there. Difficult exposure situation for the camera meter with all that snow. Footage turned out stunningly. Lots of detail....no mosquito noise...none. I'm so happy with this camera.

http://www.dvinfo.net/gallery/showimage.php?i=848&c=2
http://www.dvinfo.net/gallery/showimage.php?i=849&c=2
http://www.dvinfo.net/gallery/showimage.php?i=850&c=2

Piotr Wozniacki · February 5th, 2008, 03:25 PM

So, after all, even Bill has agreed that the camera is malfunctioning.

I'd appreciate it very much indeed if anyone recreated this with his own unit, and put the result in this thread. Only then will I know for sure if it's only my camera that needs servicing, or a general firmware flaw that can hopefully be ironed out by a firmware update.

Steven Thomas · February 5th, 2008, 03:36 PM

Yes, I 'll get around to it.
Bill, that last shot looks great man!
http://www.dvinfo.net/gallery/showimage.php?i=850&c=2

Bill Ravens · February 5th, 2008, 03:54 PM

Thanx, Steve.
I used to live in Tempe. I ventured south to CG on many occasions.
Spring training is coming up soon, isn't it?

Mark David Williams · February 5th, 2008, 04:06 PM

If the white areas in the sky are a result of being blown out and would have been blue. If the iris was closed a bit more. If the areas around the tree branches twigs etc was blocking light then those areas could possibly have a blue aura? It sounds logical to me.

The colour temperature is set wrong and is too blue, adding to this. I wonder how the image would look taken in camera at the correct temp? I corrected the colour temperature in AE and still there is a blue cast around the trees but also some areas of white. The problem is not uniform. I dont think the camera is at fault at this point. Its going to be interesting to follow this.

Bill Spence · February 5th, 2008, 04:18 PM

As we all know, you either expose for the sky and the foreground is underexposed, or expose for the foreground and blow out the sky. As to why this is happening in the camera, I do not own one so cannot say. But if you want your cake and to eat it too, you can always use a grad filter and you would be golden.

Bob Grant · February 5th, 2008, 04:56 PM

It is severly overexposed. The sky is clipped. One of the somewhat more expensive cameras that I use used to clip to purple. Wasn't really seen as a big issue although it got fixed. The Redone clips to pink if pushed.

The EX1 is more of a digital cinema camera than a video camera. As has been said by many, if you don't know what you're doing with it you can very easily get yourself into an ocean of grief. If you really want to tweak things then you're either going to have to learn a lot or have a monitor hooked up off the HD-SDI port. Perferably one with scopes built in as well. From what I've seen so far the composite SD port does not give you the true picture of what the camera is recording.

And yes, I know a few people who've been using all manner of video cameras for decades. They're having a hard time understanding how cameras such as the EX1 work and how to wrestle the best possible image out of them. This camera does go to 11, use it with caution.

Have a look at the histogram for the blue channel, look pretty badly clipped to me.

February 5th, 2008, 02:38 PM	#53
Piotr Wozniacki Inner Circle Join Date: Aug 2006 Location: Poland Posts: 4,086	Bill, Yes I am aware of how mfx decodes in 8bit vs 32bit Vegas projects, and belive me this is not the source of the problem. With 32bit, applying the Computer RGB to Studio RGB convertion is barely visible; in 8bit the difference is more apparent (right half of the grab below is converted to Studio RGB; while the superwhites are remapped, the blue "shadow" behind the trees is still there). But believe me, Vegas is not the factor; in fact I only use it take grabs from timeline. The problem is clearly visible by just playing the file with WMP. Attached Thumbnails __________________ Sony PXW-FS7 \| DaVinci Resolve Studio; Magix Vegas Pro; i7-5960X CPU; 64 GB RAM; 2x GTX 1080 8GB GPU; Decklink 4K Extreme 12G; 4x 3TB WD Black in RAID 0; 1TB M.2 NVMe cache drive

February 5th, 2008, 03:25 PM	#55
Piotr Wozniacki Inner Circle Join Date: Aug 2006 Location: Poland Posts: 4,086	So, after all, even Bill has agreed that the camera is malfunctioning. I'd appreciate it very much indeed if anyone recreated this with his own unit, and put the result in this thread. Only then will I know for sure if it's only my camera that needs servicing, or a general firmware flaw that can hopefully be ironed out by a firmware update. __________________ Sony PXW-FS7 \| DaVinci Resolve Studio; Magix Vegas Pro; i7-5960X CPU; 64 GB RAM; 2x GTX 1080 8GB GPU; Decklink 4K Extreme 12G; 4x 3TB WD Black in RAID 0; 1TB M.2 NVMe cache drive

February 5th, 2008, 04:56 PM	#60
Bob Grant Trustee Join Date: Nov 2005 Location: Sydney Australia Posts: 1,570	It is severly overexposed. The sky is clipped. One of the somewhat more expensive cameras that I use used to clip to purple. Wasn't really seen as a big issue although it got fixed. The Redone clips to pink if pushed. The EX1 is more of a digital cinema camera than a video camera. As has been said by many, if you don't know what you're doing with it you can very easily get yourself into an ocean of grief. If you really want to tweak things then you're either going to have to learn a lot or have a monitor hooked up off the HD-SDI port. Perferably one with scopes built in as well. From what I've seen so far the composite SD port does not give you the true picture of what the camera is recording. And yes, I know a few people who've been using all manner of video cameras for decades. They're having a hard time understanding how cameras such as the EX1 work and how to wrestle the best possible image out of them. This camera does go to 11, use it with caution. Have a look at the histogram for the blue channel, look pretty badly clipped to me. Attached Images

February 5th, 2008, 11:53 AM	#46
Leonard Levy Trustee Join Date: Feb 2006 Location: USA Posts: 1,684	Maybe I'm over-reacting here - and my head did tend to gloss over some of the technical analysis - but i still find myself disturbed taht an ordinary setting on the EX-1 would do this. I'm not comparingm it to V1's or any other 1/2" "semi-professional" cameras , but rather to run of the mill 2/3" professional Sony & Ikegami cameras taht I've been using for many many years. You should be able to shoot decent looking pictures in standard gamma without being terrified that if you overexpose your sky the picture will start artifacting. To me its completely unacceptable. Now I don't ever recall seeing this with any semi-pro video camera either like an DVX100 or an HVX200 or even a PD100 for that matter. It sounds like the only thing you did unusual was add some saturation to the matrix - is that right? Am I over-reacting here? I mean this is a totally ordinary shooting situation. Maybe you are right that you need to avoid the standard gammas. - that would be a drag. Did you try anything other than STD 3?

February 5th, 2008, 12:05 PM	#48
Leonard Levy Trustee Join Date: Feb 2006 Location: USA Posts: 1,684	Thanks for posting this Poitr and i will do some test myself. I haven't really tested this camera very carefully just assumed that ordinary circuits like this would work properly. As I mentioned I have seen sony send out misadjusted auto knee circuits on top end $50,000 cameras in the past so I'm hoping that's all it is.

February 5th, 2008, 12:33 PM	#49
Steven Thomas Trustee Join Date: Sep 2005 Location: Gilbert, AZ Posts: 1,896	Well, there's no doubt that it does look odd with your std gamma examples. I'll have to try to recreate this problem. I guess I have not seen it, since I mainly use cine curves.

February 5th, 2008, 12:37 PM	#50
Bill Ravens Join Date: Nov 2001 Location: santa fe, nm Posts: 3,264 Images: 10	Piotr... Your image41 is not the same one that I saw that was very overexposed. Image41 definitely looks very strange...actually, it looks like the white balance settings are off.

February 5th, 2008, 02:10 PM	#52
Bill Ravens Join Date: Nov 2001 Location: santa fe, nm Posts: 3,264 Images: 10	Piotr... when you switched to 32-bit processing, did you check the Vegas WFM for clipping? Ordinarily, when I switch between 8-bit and 32-bit, I need to apply a correction, depending on the codec type. One can't arbitrarily turn on 32 bit without adjusting levels. For example, .mxf files, I can drop a native .mxf file on the timeline in 8-bit and the levels look right, black is at IRE16 and white is at IRE235. If I switch to 32 bit, suddenly black is at 0(-8% IRE) and white is at 255 (108% IRE) These values are techncally blown out if you're looking at a studio RGB monitor. A Level correction converting computer RGB to studio RGB is needed to correct the images.

February 5th, 2008, 02:53 PM	#54
Bill Ravens Join Date: Nov 2001 Location: santa fe, nm Posts: 3,264 Images: 10	Guess I'm with Steve Thomas. Other than my initial foray into STD curves, which I abandoned very quickly, I don't use them much. I'll look at this some more to see if I can make my cam malfunction like this. In CINE mode, all the manual knee adjustments are disabled. In STD mode, auto knee is turned on. I'm not sure how this functions. Could it be that the camera processor pushed the knee out to an irrational setting to cause what you're seeing? I must say that I just finished shooting a 240 sec short ...lots of gray skies, snow everywhere, a few patches of blue here and there. Difficult exposure situation for the camera meter with all that snow. Footage turned out stunningly. Lots of detail....no mosquito noise...none. I'm so happy with this camera. http://www.dvinfo.net/gallery/showimage.php?i=848&c=2 http://www.dvinfo.net/gallery/showimage.php?i=849&c=2 http://www.dvinfo.net/gallery/showimage.php?i=850&c=2

February 5th, 2008, 03:36 PM	#56
Steven Thomas Trustee Join Date: Sep 2005 Location: Gilbert, AZ Posts: 1,896	Yes, I 'll get around to it. Bill, that last shot looks great man! http://www.dvinfo.net/gallery/showimage.php?i=850&c=2

February 5th, 2008, 03:54 PM	#57
Bill Ravens Join Date: Nov 2001 Location: santa fe, nm Posts: 3,264 Images: 10	Thanx, Steve. I used to live in Tempe. I ventured south to CG on many occasions. Spring training is coming up soon, isn't it?

February 5th, 2008, 04:06 PM	#58
Mark David Williams Major Player Join Date: Dec 2007 Location: Hertfordshire UK Posts: 414	If the white areas in the sky are a result of being blown out and would have been blue. If the iris was closed a bit more. If the areas around the tree branches twigs etc was blocking light then those areas could possibly have a blue aura? It sounds logical to me. The colour temperature is set wrong and is too blue, adding to this. I wonder how the image would look taken in camera at the correct temp? I corrected the colour temperature in AE and still there is a blue cast around the trees but also some areas of white. The problem is not uniform. I dont think the camera is at fault at this point. Its going to be interesting to follow this.

February 5th, 2008, 04:18 PM	#59
Bill Spence Regular Crew Join Date: Nov 2007 Location: Indianapolis, IN Posts: 29	As we all know, you either expose for the sky and the foreground is underexposed, or expose for the foreground and blow out the sky. As to why this is happening in the camera, I do not own one so cannot say. But if you want your cake and to eat it too, you can always use a grad filter and you would be golden.