GH1 Color Shifting Issue

Thanks for the solid analytical work and trouble shooting Luis and Stephen and SonicStates.
Seems such an obvious issue. Surprised it hasn't come up earlier!
 
I tried a few test shots while I was out shooting today. I've not come across this problem before and so thought that I wouldn't be able to recreate it. I tried a few tilts up to a blue sky with an OM manual lens in a few film modes and got nothing. I later tried with a ZD 14 45 kit lens from my old e300. I didn't think I had recorded this shift at all until I looked through the footage a second time. At the end of one of the shots, over the last few frames, I got a considerable shift of blues, not a jump in exposure, but a weird shift in the blue channel, just as the OP has demonstrated.

I tried most of the film modes, but this only happened whilst using the Dynamic preset. Shooting with a 1080 25 camera, so it looks like this problem might not be restricted to US/Japanese models.
 
I tried a few test shots while I was out shooting today. I've not come across this problem before and so thought that I wouldn't be able to recreate it. I tried a few tilts up to a blue sky with an OM manual lens in a few film modes and got nothing. I later tried with a ZD 14 45 kit lens from my old e300. I didn't think I had recorded this shift at all until I looked through the footage a second time. At the end of one of the shots, over the last few frames, I got a considerable shift of blues, not a jump in exposure, but a weird shift in the blue channel, just as the OP has demonstrated.

I tried most of the film modes, but this only happened whilst using the Dynamic preset. Shooting with a 1080 25 camera, so it looks like this problem might not be restricted to US/Japanese models.

they sky? i'm thinking it has to do with the blue channel being hidden in the shadow is what's causing the camera to compensate for it. dunno. just so far the boat, curtains, have all been under some type of shade.
 
Shooting a landscape with mountains beyond, about a 50/50 split. Then tilting up to blue sky and down. The weird thing is, the shift didn't happen during the tilt, but just as I bumped the camera to stop the shot. I tried a few attempts in different film settings and didn't get anything.
 
Hmmmm..........I guess the GH1 is not a fan of lakes.

We all know this must be something to do with the kit lens corrections...do you think it has something to do with the chromatic aberration correction? Is it maybe thinking that the place these colors meet is an instance of chromatic aberration and is trying to correct it somehow? Maybe not exactly that but I am sure this must have something to do with chromatic aberration correction...that and it's fun to say.
 
Ben, I don't think this can be a kit lens thing, as I was shooting with an Olympus lens and Sonic was shooting with a Tokina. Is everyone sure that iExposure was off when this happened. I was switching between off and standard while trying this and the only time it happened was when iEposure was on. Might be no link but worth checking at least.
 
We all know this must be something to do with the kit lens corrections...
We don't know that for sure. Someone's claimed to have reproduced the problem with a manual lens.

do you think it has something to do with the chromatic aberration correction? Is it maybe thinking that the place these colors meet is an instance of chromatic aberration and is trying to correct it somehow? Maybe not exactly that but I am sure this must have something to do with chromatic aberration correction...that and it's fun to say.
Chromatic aberration is color fringing around objects. I gather that it's not easy to correct simply by shifting values in a color channel. To my eyes, what's happening in the footage almost seems like a white balance freak-out.
 
Ben, I don't think this can be a kit lens thing, as I was shooting with an Olympus lens and Sonic was shooting with a Tokina. Is everyone sure that iExposure was off when this happened. I was switching between off and standard while trying this and the only time it happened was when iEposure was on. Might be no link but worth checking at least.

In my case, and with Luis' test footage, iExposure was off.
 
OK, so it looks like the stock lens or iexposure probably aren't the culprits here. Here is the shot where I managed to induce the shift, it happens on the last few frames. Camera is a European model, using an Olympus 14-45 Four Thirds lens. Dynamic mode, 1080 25.

I can't get the embed to work so will just add the link

http://vimeo.com/7070411
 
Last edited:
Whats the deal with the round lines in the sky on GH1 footage...sky is often kind of segmented looking....I assumed this was the result of color sampling and the codec but now I'm wondering if it's not the kit lens..
 
are you talking about some kind of banding Ben?

Wow I typed a response on a spotty wifi connection and it didn't take :(

Here's what I am noticing. Look at the sky in that clip that was posted on this page. Imagine the image circle. Now look at the sky and you will see little circular bands following the arc of the image circle (roughly.) Not sure if they move with the image (codec issue) or if they are static (sensor banding of some new kind) or are a lens issue, which given the nature of the kit lens could affect the image in either way.

I've noticed it in some of my own footage as well, and it is aggravated on color grading. Will post some screen grabs @ some point.
 
Wow I typed a response on a spotty wifi connection and it didn't take :(

Here's what I am noticing. Look at the sky in that clip that was posted on this page. Imagine the image circle. Now look at the sky and you will see little circular bands following the arc of the image circle (roughly.) Not sure if they move with the image (codec issue) or if they are static (sensor banding of some new kind) or are a lens issue, which given the nature of the kit lens could affect the image in either way.

I've noticed it in some of my own footage as well, and it is aggravated on color grading. Will post some screen grabs @ some point.

Ok actually it seems to be coming in a circle like if you made circles out from the sun. Here is a screen grab that I crunched on a bit in post and made black and white so you can see what I am talking about....looks like crappy codecness to me, but I don't recall seeing it with non-kit lens stuff. Pretty sure I usually see it @ 14mm.

We may need a name for this...sun-swathing?

Color corrected to show (and less frequent, larger swaths)

screenshot20091015at223.png


Original (more frequent, smaller swaths)

screenshot20091015at222.png


I can change color correction sliders (mainly mids) to change the frequency of the swaths, the size, and the proximity to the sun (right side)
 
Back
Top