Topic: Panasonic GH4 problems with 'stills' (Read 27112 times)

bengedlow · « **on:** January 06, 2015, 11:46:20 am »

My first post on Luminous Landscape. I've got an issue with the Panasonic GH4. Video is perfect – what I see in the LCD or viewer is identical to what arrives in FCPX or Premiere Pro. The stills though, both RAW and JPEG, come into the computer about 5-8 stops too dark. Where should I post with an issue like this?

All ears,

Ben

bengedlow · « **Reply #1 on:** January 06, 2015, 12:07:02 pm »

Just to add to my previous post, now that I know where I should be posting:

I'm not using any in-camera effects on the stills, as far as I can figure. Other than cutting back on the contrast. When I examine the still in-camera, it looks just fine. Even zooming in very close, I see the exposure I expect, and there is a lot of detail in the shadows. When I import the stills into Aperture, or even using the SilkyPix software that comes with the camera, the image is very very dark. I can pull up the exposure and all the details seem to be there ... but in Aperture I have to pull it up right to the very top and it creates weird artefacting and noise and colour blotching. Go figure. With SilkyPix or Photoshop it seems to be alright, once the exposure is corrected (and it takes a lot of correcting), but I'm very nervous about having to correct what was otherwise (according to the camera) a perfectly exposed picture.

I shot some JPEG and RAW back and forth. Seems as I'm having the same issues with both.

Slobodan Blagojevic · « **Reply #2 on:** January 06, 2015, 12:40:31 pm »

It seems that you are getting a linear rendering upon import, instead of gamma-corrected. However, I do not know what might be causing that.

bengedlow · « **Reply #3 on:** January 06, 2015, 12:55:19 pm »

Hi Slobodan,

One thing I notice: when I import the stills into Aperture, as I select them in Aperture there is a very brief moment when they pop up much lighter - half a second - before turning very dark again. As if the app is seeing it one way, then immediately switching it to another.

I'm not too familiar with the protocols of RAW (though this is happening with the JPEG's too), and am wondering about that - linear vs. gamma corrected.

Ben

spidermike · « **Reply #4 on:** January 06, 2015, 03:54:24 pm »

That happens with me in LR when I import files from Canon. I have been told that the program is instantaneously seeing the in built jpeg before presenting the raw file for editing (this part I'm more dubious about: apparently even if you shoot raw-only the camera retains in the 'style' in the metadata and picks that up before ignoring it).

bengedlow · « **Reply #5 on:** January 06, 2015, 04:49:18 pm »

Hi Spidermike,

That makes sense. Thank you. Now if I can just figure out when it kicks in to reveal the RAW file, the file is 5 stops darker than it was in the camera. I wish I knew a Panasonic GH4 techie like I know a few Sony techies.

Slobodan Blagojevic · « **Reply #6 on:** January 06, 2015, 04:50:07 pm »

Mike, the question still remains why would LR (or any other program) see a file so underexposed?

spidermike · « **Reply #7 on:** January 06, 2015, 06:55:58 pm »

I really do need to improve my reading skills!
The cases I have encountered do not show that level of difference in exposure so maybe it is not the same reason.

The picture you see on the LCD is a jpeg rendition according to the profile you have set in camera so if you are exporting raw and jpeg you should have at least a jpeg that matches the image on the camera LCD.
What happens if you shoot jpeg only?

The fact you can correct exposure by 5-8 stops and retain what seems to be all detail suggests the image is OK buyt is being rendered weirdly.

Have you tried a factory reset?

bengedlow · « **Reply #8 on:** January 07, 2015, 10:33:46 am »

Spidermike,

That's interesting. I did do a RAW and then a JPEG of same shot. Both were dark. I did do a reset of camera after I got the first set of 'dark' shots. Then did another shoot, and got the same problem.

This is one of those mysteries that pops up and I don't even know where to look for an answer. I've been bopping around the internet trying to find a conversation about the same issue, but am coming up with nothing, not a hint. I have checked the shots on three different computers, even a PC, with same results. Perfect in-camera. Very very dark in the computer.

Sigh...

Ben

Slobodan Blagojevic · « **Reply #9 on:** January 07, 2015, 11:01:35 am »

Time to contact Panasonic, I'd say. Seems to me something is majorly wrong or broken in how files are tagged in-camera for external reading.

bengedlow · « **Reply #10 on:** January 07, 2015, 01:00:45 pm »

Thank you Slobodan,

I did try Panasonic, online, a pleasant conversation with a techie, but he didn't seem to want to take it beyond the old, "must be a computer issue".

I guess I have to try the primitive way to communicate ... by telephone. Wish me luck. Will report back when I find out whatever it is.

All the best,

Ben

spidermike · « **Reply #11 on:** January 07, 2015, 01:16:25 pm »

The logic to me says it is the camera in some way
Multiple computers with the same problem - unlikely to be the computer
Multiple programs with the same problem - it is highly unlikely that you put the same import settings on each program
You have done a factory reset - it is unlikely to be a setting you put in

Which logically leaves the camera program. And with the level of difference you say you have I very much doubt it is how the LCD is set up to replay your images

The only other thing it could be is that Panasonic has in-built correcton for many aspects, although as far as I know this applies only to distortion and aberrations.

spidermike · « **Reply #12 on:** January 07, 2015, 01:18:37 pm »

Are you in manual mode?

As soon as I pressed 'post' I decided to google 'GH4 automatic correction' and this came up. Any help?
http://www.dpreview.com/forums/post/54213632

Quote

Digital Imaging Technician wrote:

This drives me crazy. Even when I’m in manual mode (and not using auto ISO) the screen always show "the right" exposure. I want it to show what the exposed picture will look like, not some corrected image.
How can I fix this?

See the documentation: "Confirm the Effects of Aperture and Shutter Speed (Preview Mode)"

For Manual Exposure Mode see [Custom] [Constant Preview].

bengedlow · « **Reply #13 on:** January 07, 2015, 02:39:13 pm »

Will check spidermike,

Thinking about that though - I'm always monitoring the exposure and shutter speed in the viewer, and I don't remember seeing anything that suggested some kind of viewer-correction might be happening. Everything 'looked' as it should. But thank you for that, at least it's somewhere to start 'looking'.

As I can tell, I'm always in full manual mode. I spend a lot of time trying to figure out all the things I need to turn off in the menu. It's a bit disconcerting when I've set full manual mode ... and I can SEE that there is some autocorrection going on with the exposure/ISO ... drives me nuts sometimes ... and then I have to go deep in the menu and find that odd little illogical switch that has to be turned off, with a name that seems to have nothing to do with auto-correction or exposure.

That sound you hear, it's not the traffic outside your window, it's me grinding my teeth.

Slobodan Blagojevic · « **Reply #14 on:** January 07, 2015, 02:48:59 pm »

I do not have a mirrorless (i.e., with a live view on by default), but my live view cameras (Canons) have an option called Exposure Simulation. When ON, it shows the effect of exposure adjustments, e.g., if you deliberately want to underexpose by, say, 2 f/stops, the screen will go darker. When disabled, the live view image will always remain the same, no matter the exposure adjustments.

In your case, it would mean that you are deliberately underexposing by 5-8 stops, while your screen is showing "normal" exposure. Possible, but not likely. Maybe you are using 1/8000s, f/22, ISO 100 all the time in manual mode?

bengedlow · « **Reply #15 on:** January 07, 2015, 02:59:40 pm »

Nada Slobodan,

Whenever I change shutter speed, iris, ISO, I SEE the changes happening on the LCD view screen and viewer. I'm always monitoring what the camera is actually shooting - meaning on screen I see my exposure and speed numbers. All auto functions except autofocus are turned off. I have something called 'Constant Preview' turned on, because when it's turned off the camera seems to kick into some kind of weird auto exposure mode (meaning if I move from dark to light the exposure changes automatically, no adjustment by me, at least on-the-screen). I haven't tested shooting anything in the 'Constant Preview' turned off mode, so I don't know the effect it might have on the exposures. But as it's not being used by me, I don't think it applies to the issue.

I keep scrolling through the menu, and I just can't seem to find anything that suggests the viewer is not giving me a correct read. Remember, I get the same exact exposure BEFORE and AFTER (in playback mode) in the camera viewer. One would think, if I was getting a false read on the viewer when recording, I would get the REAL exposure visible in the playback viewer, right? Maybe that's a wrong assumption.

bengedlow · « **Reply #16 on:** January 07, 2015, 03:37:38 pm »

I just did another test. When shot simultaneously JPEG's are lighter by about 2-3 stops. The RAWS are the serious issue. Always much darker than what I see in-camera.

Slobodan Blagojevic · « **Reply #17 on:** January 07, 2015, 03:46:38 pm »

Quote from: bengedlow on January 07, 2015, 03:37:38 pm

I just did another test. When shot simultaneously JPEG's are lighter by about 2-3 stops. The RAWS are the serious issue. Always much darker than what I see in-camera.

Where are jpegs lighter? On LCD review or on computer? Jpegs lighter, raws darker!? That does not make sense at all.

Have you tried shooting fully automatic? On P or Auto, or whatever full auto might be on GH4.

Slobodan Blagojevic · « **Reply #18 on:** January 07, 2015, 04:05:43 pm »

Quote from: bengedlow on January 07, 2015, 02:59:40 pm

... One would think, if I was getting a false read on the viewer when recording, I would get the REAL exposure visible in the playback viewer, right? Maybe that's a wrong assumption.

That is a correct assumption. The only other explanation for "correct" playback image, coupled with much darker computer image, would be LCD brightness setting. That is, if your LCD is set to max brightness, it is possible that the image looks "good" on LCD and underexposed on computer. Though not by 5-8 stops. However, you said that movies are ok both ways, so LCD brightness should be not be the issue.

I still think something is broken in-camera, while tagging files for external viewing.

bengedlow · « **Reply #19 on:** January 07, 2015, 04:08:34 pm »

"Where are jpegs lighter? On LCD review or on computer? Jpegs lighter, raws darker!? That does not make sense at all. Have you tried shooting fully automatic? On P or Auto, or whatever full auto might be on GH4."

I will try shooting something on automatic.

The LCD screen is set right in the middle, meaning no adjustment, which is the default position. The JPEG's are lighter when brought into the computer. On the camera they look the same as the RAW files.

Author Topic: Panasonic GH4 problems with 'stills' (Read 27112 times)