3+ stops underexposed back in Color

Xandros

Xandros

Member
Hi people.

First I have to thank to Vitaliy and all of his efforts to make this camera much better than most of us could imagine.

This morning I just grab a shot with ISO 100, F5.8, mjpeg 720p 4:2:2 and few with AVCHD 1080 just to compare how much can we go with color grading in Apple Color.

I was very impressed when I've seen what it can be done with 8bit mjpeg. It's quite hard for me to accept that I am shooting with camera which is not film or RED (just have to swich in my head) like I did last years.

First, the Color screenshot and video sample:

Screenshot2010-07-22at155803.png


Underexposed following by corrected
http://www.vimeo.com/13556524

Otherwise, I hate the Panasonic's implementation of AVCHD and very very high compression in parts with no details or shadows. I've found that's very hard to grade a clean sky or bring details from shadows. It's definitely AVCHD. In comparance with that mjpeg is very very good (some times I can't believe that I am working with mjpeg).

I miss 24p/25p and 50p/60p in mjpeg definitely.

I am using this settings for mjpeg 4:2:2 now:
150,4
120,4
110,4
95,4

Card Kingston Class 4 (but I feel it's working as class 6). My class 10 Kingston died same day when I bought it.

With this settings I have from 45 to more than 50 mbits datarate. Also with this Class4 card I've got about 55mbits with 1440x1080 4:2:0.

Hope will catch more free time to test camera in depth.

All the best!
 
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pianoboy said:
Wow, that's amazing!
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Yes it is. I would love to see that same comparison done with an AVCHD clip for comparison.

I think the hacked MJPEG is a very powerful format when it comes to image quality. Too bad we have the playback issues. Nonetheless, it is certainly a great format for some kinds of shooting.
 
WTF??? That's incredible!

Modified AVCHD is no slouch either, but there's no way you'd recover 3 stops like that with it. Awesome test.
 
That is absolutely SCARY!!!! WOW!!!!!!!!!!!! I'm still freaking out over the fact that my GF13 is now manual control. (I have the GH13 also) Now THIS!!!??? How am I supposed to sleep at night? I SWEAR!! Thanks for posting!!
 
Xandros said:
Hi people.

I am using this settings for mjpeg 4:2:2 now:
150,4
120,4
110,4
95,4

Card Kingston Class 4 (but I feel it's working as class 6). My class 10 Kingston died same day when I bought it.

With this settings I have from 45 to more than 50 mbits datarate. Also with this Class4 card I've got about 55mbits with 1440x1080 4:2:0.

Hope will catch more free time to test camera in depth.

All the best!
Click to expand...


I also really dislike the AVCHD look. The VPN is the thing for me and in low light it really becomes a problem on flat surfaces, skies etc. If you try and grade these areas it only makes it worse. But AVCHD has the frame rates I need and since the MUD issue is very much reduced, (it's still there but just not so bad at all) it is the best to shoot the majority of stuff with.

Even with modulrs MJPG safe settings,

150,86
130,56
115,26
100,4

I am getting fairly clean Mjpg which is great to grade. It holds up surprisingly well considering how much this camera costs. There are still some issues I can see.


This picture is raw direct from the camera. Details of settings used are included at the bottom of the frame. It looks pretty decent, apart from my rather crap focus.

mjpg-001.jpg


The picture below shows a still from a MJPG movie with the Modulr Settings, that I placed in After Effects and graded quickly with Magic Bullet Looks.

mjpg-002.jpg


Next a 160% scale detail showing just the red channel

mjpg-003.jpg


160% scale detail showing just the green channel

mjpg-004.jpg


and finally 160% scale detail showing just the blue channel

mjpg-005.jpg


Blue channel really contributes to the poor macroblocking. I wonder if there is a way to selectively alter the way the codec compresses each channel.


So do the settings you have produce little compression. I'd like to try these settings you have, but can you tell me if you get playback in camera? Also with the 1440x1080 settings are you able to do 4.2.2 and get playback or is that a no no?

A friend sent me a clip from his 7D transcoded to Pro Res and I have to say it was really impressive. Hardly any grain, and sharp but not too much. I think the h264 is a miles better codec than AVCHD. I am sure if you go to the mental settings for AVCHD you get better quality, but at the expense of in camera playback which is not brilliant. I also think VPN is just inevitable with AVCHD, or at least it is with this camera.

Still mjpg is very much on a par if you pimp it to the max I think.

all the best

Richard
 
Back in June when I was testing mjpeg, i noticed the ability to bring back details from the shadows. Both AVCHD at 50+mbits and Mjpeg at 70Mbits+ are both quite good.

Here are lowlight shots that Mjpeg recorded very good considering how dark it was
http://www.dvxuser.com/V6/showpost.php?p=2017000&postcount=93

More Mjpeg shots
http://www.dvxuser.com/V6/showthread.php?t=212609
http://www.dvxuser.com/V6/showpost.php?p=2019902&postcount=109

**Test blow up of 720P Hibit rate MJPEG MODE to 1920 and beyond.
http://www.dvxuser.com/V6/showpost.p...5&postcount=29


Pappas
 
reggietelly said:
Blue channel really contributes to the poor macroblocking. I wonder if there is a way to selectively alter the way the codec compresses each channel.
Click to expand...

Wouldn't white balancing help this?

Or how about filtering the light spectrum at the lens so the recording is skewed away from the blue channel, and then in post, bring the color balance back in to balance......
 
The shot wasn't white balanced but it was a strange overcast day and this was honestly nearer to what it looked like than any of the presets.

The macroblocking is difficult to see in the blue screen grabs but it's definitely there. I am sure I read somewhere that the blue channel misses out, because green and red are the colours in skin tones. Maybe that was for DV. Still it surprised me that both red and green would be pretty smooth and blue wasn't. Maybe it's time to do some tests.

all the best

Richard
 
Actually, I think you want to do just the opposite. Get more blue color to the sensor, and then use the post processing to boost the red and green.

Of course, it may be moot because it may have more to do with the MJPEG routine than the amount or quality of blue channel info that the sensor gets. I'd be inclined to experiment with different (lower) Table settings before I started messing with color balance changing ideas. I think the blockiness in the blues that we see could be as much a matter of the nature of this photo as anything else. Given a different photo we might see more blockiness in the greens.
 
reggietelly said:
The shot wasn't white balanced but it was a strange overcast day and this was honestly nearer to what it looked like than any of the presets.

The macroblocking is difficult to see in the blue screen grabs but it's definitely there. I am sure I read somewhere that the blue channel misses out, because green and red are the colours in skin tones. Maybe that was for DV. Still it surprised me that both red and green would be pretty smooth and blue wasn't. Maybe it's time to do some tests.
all the best
Richard
Click to expand...

Maybe this is why it might be worth boosting the blue spectrum at the lens- to feed the sensor more blue- then color balance in post. Just a hypothesis though.



wturber said:
Actually, I think you want to do just the opposite. Get more blue color to the sensor, and then use the post processing to boost the red and green.
Click to expand...

Shoot through a blue filter- then shoot the same clean. Check the channels after wards and see if there is a difference. Of course you could try setting the kelvin to 2800K and see if this changes anything as well. Of course changing the color frequency spectrum at the lens would seem to feed the sensor more directly-
 
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The more I think about this the more I find it odd that the blockiness is apparent only in the blue channel. The JPEG isn't storing the info as R,G,B info. It is storing it as 4:2:2 YCbCr. I'd think that the luminance channel should have extra detail and the two color difference channels should be the channels to show blockiness (if any) since they have half the number of samples.
 
PappasArts said:
Shoot through a blue filter- then shoot the same clean. Check the channels after wards and see if there is a difference. Of course you could try setting the kelvin to 2800K and see if this changes anything as well. Of course changing the color frequency spectrum at the lens would seem to feed the sensor more directly-
Click to expand...

FWIW, still camera color filter arrays typically have lower sensitivity through the blue and red filters with daylight "white". So these colors typically are noisier than the green channel after the in-camera color balance boosts them to bring them in balance.
 
reggietelly said:
The shot wasn't white balanced but it was a strange overcast day and this was honestly nearer to what it looked like than any of the presets.

The macroblocking is difficult to see in the blue screen grabs but it's definitely there. I am sure I read somewhere that the blue channel misses out, because green and red are the colours in skin tones. Maybe that was for DV. Still it surprised me that both red and green would be pretty smooth and blue wasn't. Maybe it's time to do some tests.

all the best

Richard
Click to expand...


Probably a stupid question but...

I note that in the still image you state that saturation was +2 ... is it correct to assume that a positive sign implies some kind of "gain" (for my lack of proper terminology) and hence "noise"?
I seem to remember that many shooters were choosing to set the parameter negatively in order to process / "amplify" (again, pls excuse my audio culture) in a better performing environment, i.e. the workstation...

Thx

Paul
 
Uncle GroOve said:
Probably a stupid question but...

I note that in the still image you state that saturation was +2 ... is it correct to assume that a positive sign implies some kind of "gain" (for my lack of proper terminology) and hence "noise"?
I seem to remember that many shooters were choosing to set the parameter negatively in order to process / "amplify" (again, pls excuse my audio culture) in a better performing environment, i.e. the workstation...

Thx

Paul
Click to expand...

I find Nostalgia to be very good at adding detail to shadows, it's a flatter image which means you can play with it more later. However the downside, for me at least, is it's lack of saturation. So I have upped it knowing I will up it even more in post later. Does anyone know if it adds gain to the colour because if so I'll turn it down or maybe use smooth. I just like the shadow detail it brings out. There's only so much you can do with the picture in FCP or After Effects before it starts to breakup so I try to do as much in camera as possible. That's not necessarily the way other people like to do it but the closer you can capture colour wise the less you have to do after. That said I turned the camera back to standard today as I was shooting green screen and it looked the best out of all the film modes.
 
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