106 replies to this topic

[Drew]

Simon, if you have the time, can you post the vectorscope and waveforms of the original AVCHD file for the clips with the green/cyan cast?  I'd like to see how much clipping there is in the G channel.  I think that cyan/green cast can be removed from the clips with a good grader like Resolve.

[peterbkk]

Ah Simon,

 

I think that I see your problem.  What can you expect if you shoot video of a "shitter graveyard"  That's your problem: shitty subject matter...   

 

Seriously, I recognise many of those problems from the Sony CX-550 underwater: excess green, red fuzzies, low DR.  My guess is that Sony have used the same colour engine.

 

I also recognise the nice Canon underwater colours.  My XF-100 does that.  Just gotta change the preset for each depth range and almost no post colour work is required.

 

I did have some success with the Sony CX-550 by doing a MWB on a brown subject (e.g. brown coral, rust) as that seemed to damp down the problems in the red channel.  But, at depth, I used to have to mix in some video light onto the subject to get it to even accept the MWB.  Fiddly and hit-and-miss.

 

If it is the colour engine, I wonder if you could reverse engineer some external gel filters that offset the camera's problems.

 

Or. eBay it and buy a Canon...

 

Regards

Peter

[SimonSpear]

Shitter Graveyard - hehe at least that put a smile on my face Peter!    In addition to the 7D's I've also got a PMW200 which is working out amazingly well, so its not all Sony cameras that are affected.  It's not just the single chip ones either as the NX5 was also badly hit by all accounts, although very few people actually got one of those underwater.  So right now it looks like the whole NXCAM range is pretty much useless for underwater shooting.

 

The CX550 was a great compact camera, but quite frankly you'd expect a whole load more from the FS100.  I use the FS100 extensively topside and it is my favourtie camera which just makes this all the more frustrating.  Still you made a good choice with the XF100 - I've seen quite a bit of underwater footage from it and I was very impressed.

 

Drew I've attached a screen grab of FCP scopes which is what I think you are looking for.  I don't have Resolve installed at the moment, but I'm very happy to make some files available for you or anyone else to play around with if you think you can find a work around?  Whenever I've colour corrected in FCP I just get the halos appearing and the more red you add the worse they get.

 

Cheers, Simon

 

Attached Files

•  Scopes.tiff   430.74K   14 downloads

[thani]

Hi guys,

 

It is good to know that you are trying to get to the bottom of this issue. What I have said about this issue is summed up in the quote below.

So whomever is trying to recreate this promeblem must aim the camera at a subject/fish surrounded by huge column of water. Blue or green water does not matter. Low ambient light is required.When shooting close-ups, the camera behaves well.

I will be posting a clip - it shows better in video - that demonstrates the UGLY effect while shooting a fish in the vast ocean while on the same day, same site, the close-up shot has no issue.

 

Hi Simon,

Did You think the wide angel is sharp enough?

My biggest worry is not WB now, it is what you have noticed in images 4 & 5. I have seen the same horrible HALO like rings of pixelations/noise in Sultan's clips.

This happens when the camera is aimed at the vast blue/green water even when it focuses correctly at a small fish/subject in the middle or the side of the frame. Sometimes it is a multiple animated rings. May be
it is due to gain which we were limiting to 18db.

It is more obvious in the clips than the stills. We thought, initially, that something went wrong with the FS700 but we got the same with the FS100. Again, This happens only when you have large background of water in the scene.

I hope I am wrong. What do you think Simon?

Regards,
Thani

 

Here is the clip. Try watching it in HD. Youtube compresion has softened the effect:

Edited by thani, 27 May 2013 - 11:09 AM.

[thani]

BTW, the shots in the above video were not color graded and were recorded directly on Ninja2 as Pro Res HQ

Edited by thani, 31 May 2013 - 06:48 AM.

[peterbkk]

Wow, that halo is bad.
 
It doesn't look like it has anything to do with the subject, as the "halo" does not follow the subject but stays centred.  If there was no subject, just water, and the lens was manually focused somewhere between 1 meters and infinity, does the halo circle appear?
 
Could it be something to do with parallel light reflecting around between the lens and the sensor, created when the lens is focused out past 1 meters distance.  If so, that ought to be repeatable on land in similar lighting conditions.

Maybe a different lens / port might get rid of it?
 
Regards
Peter

Edited by peterbkk, 31 May 2013 - 07:16 AM.

[thani]

Peter,

For sure, It is really bad. And the subject may have nothing to do with it. The camera was trying to focus on the subject in bad visibility. And hence there is so much green water around and the camera is trying to compensate for such color cause of manual white balance, the camera goes crazy in the color rendition process. The lens used I think was the wonderful E-mount Zeiss 24mm 1.8.

As I said the camera does a good job in closeup shots.

This is some old footage that Sultan shot that and took me sometime to find. Unfortunately, I don't have access to the camera and can't do more trouble shooting. The guys here mentioned in this thread similar issue reported on land but I guess it is quite rare.

Regards,
Thani