Luminous Landscape Forum
Equipment & Techniques => Digital Cameras & Shooting Techniques => Topic started by: bengedlow on January 06, 2015, 11:46:20 am
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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
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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.
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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.
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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
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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).
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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.
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Mike, the question still remains why would LR (or any other program) see a file so underexposed?
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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?
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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
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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.
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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
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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.
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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
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].
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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.
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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? ;)
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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.
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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.
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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.
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... 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.
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"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.
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... The JPEG's are lighter when brought into the computer. ...
Wait, are jpegs on the computer 2-3 stops lighter than: 1. raws on the computer or 2. the same jpegs on LCD?
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Can you link to a jpg and raw so that some of us can try different LR installs?
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Hi Mike,
Yes!
Give me a bit to figure out how to do this (links to files uploaded). I do it so rarely I forget the process. Will put up a couple of samples shortly.
Ben
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Hi Mike,
I'm in the middle of cutting a complicated film, on deadline, and my brain hurts. Is there an instruction or tutorial for how to put up a single photo on the web so you can access it with a URL? I've completely forgotten how to do it. And my Googling isn't giving me any results.
Ben
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I'm sorry I don't know how you host things. In fact my website won't allow me to link raw files, only jpgs. I think you could use dropbox or some other free file service (with limited capacity). Make sure you load up the matching raw and jpg.
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Will research and get back to you. I use DropBox and WeTransfer ... so I can send files to any email address, but I'll figure out how to do the linking thing ... and report back.
B
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Hi Mike,
I'm in the middle of cutting a complicated film, on deadline, and my brain hurts. Is there an instruction or tutorial for how to put up a single photo on the web so you can access it with a URL? I've completely forgotten how to do it. And my Googling isn't giving me any results.
Ben
Ben,
Go to www.yousendit.com then register for free, send yourself the file via their site. This will yield an URL, and you can post this URL here. The advantage is there is no software to install. Otherwise dropbox is fine AFAIK.
Edmund
Edmund
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Edmund,
Aha! That's the way one does it. Yes, I use YouSendIt and WeTransfer regularly. I had forgotten that a URL is produced by doing this. I will organize my stills and do this today.
Thanks for the tip.
Ben
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Just curious, you haven't tweaked any kind of profile in the camera, have you? You said the video is coming out perfectly, so what do you have for your settings? If it is anything like my former Nikon and current Olympus, the settings you set to get your video should also affect how it renders the jpeg, but not the RAW. Just a theory that I haven't seen anyone else mention. But I could be totally wrong on this thought.
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SZRitter,
I shoot video in the 4K Cinema mode. I switch to 'M' to shoot stills. Canon/Nikon people tell me that what you see in the viewfinder is not necessarily what you are exposing. Which makes sense in a DSLR camera viewfinder. And I've never quite understood why those cameras don't allow one to SEE ones adjustments on the LCD monitor. Perhaps there is a setting that allows this - but not a single Canon or Nikon user that I know has been able to show me. The GH4 has a 'Preview On' switch, which seems to always show exposure changes. I can see the exposure changing as I make adjustments - so my assumption is that the changes are literal. If I shut off the 'Preview On' mode, then when I move the camera through varying light I can see the camera making auto-adjustments, pumping up and down, even though I'm in full manual mode. Which I don't quite get. I'm going to see if I can put up one of my problematic RAW files ... and put a link here shortly.
B
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Hi Gang,
I've put up two files, the RAW file, and a JPEG. The JPEG wasn't shot in camera, I made it from the RAW to give you an idea of what the image looks like in-camera, perhaps even slightly brighter. So that's my issue. In-camera all my RAW stills look like the JPEG uploaded here, but when they are brought into the computer (two different Macs, one PC), they look like the RAW file uploaded here.
http://we.tl/cWFMgUVxJC
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That look more like 2 f/stops difference, not 5-8, but still...
Try reducing LCD brightness on camera one or two positions from the middle (I do one on my camera). Also, try shooting a gray card with a spot meter, rather than a high-contrast scene with a center-weighted one, as in your case.
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Hi Slobodan,
Now that's interesting!! Perhaps you are getting a different read on your system?? They are at least five stops darker on my system. If they were only two stops I might live with them. I don't think I'm exaggerating – I've been behind a camera, professionally, since I was fifteen years old; that's half a century or more, ouch.
One of the reasons I haven't just 'adjusted' the LCD screen ... is that for two months after I got the camera the stills were just fine, perfect. The 'dark' stills have only come into play since the last firmware update. Which makes me wonder.
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Do you think the answer to all this may be in the histograms?
I would look at that first. I am betting that OP is looking at the rear screen and (mis)judging his exposure.
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And I just went back to look at a few different shoots during the last couple of months, since the firmware update. Dark. Here's what is intriguing me - the thumbnails for all the stills are more or less perfect in Aperture, the moment I click on the thumbnail to bring up the RAW file ... bang, dark. Now why would Aperture be producing perfectly exposed thumbnails from supposedly very 'dark' original RAW files? That's the mystery, for me.
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Hi Slobodan,
Now that's interesting!! Perhaps you are getting a different read on your system?? They are at least five stops darker on my system. If they were only two stops I might live with them....
All I did in Lightroom is raised exposure by 1 and ⅔ of a stop, i.e., not even two stops:
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Do you think the answer to all this may be in the histograms?
I would look at that first. I am betting that OP is looking at the rear screen and (mis)judging his exposure.
My guess as well. Looking at the raw file histogram, it does look underexposed. The scene itself is very contrasty, containing blown highlights and deep black (i.e., in the 0-5 range) at the same time, beyond sensor's ability to cope.
I would suggest, as I already did, to shoot more evenly lit scenes, perhaps daylight, using P or Auto mode on the camera, or even "sunny f/16" rule.
My second guess, as I also mentioned before, is that the LCD is too bright, bringing it down a notch or two, plus proper exposure, might solve the problem.
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Hi Slobodan,
Thank you for doing that, very kind of you. I'm going to take another crack at talking to Panasonic. Are you on a Mac?
I just scanned another shoot. On the camera all the exposures, several hundred, are more or less within a stop of each other on the in-camera LCD screen, or in the viewer, same thing. Pulled into the computer some shots are only a stop or so under, and some about 4-5 stops under ... there is a very weird inconsistency here. To note: I shot most of the sequence with roughly the same exposure settings. I'll keep trying till I get a knowledgeable techie at Panasonic, and then report back what the conclusion was. With luck.
Thank you Slobodan...
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I did the something similar, but with +2ev I got a reading off the guys forehead to pretty well match (63/53/43). I don't know anything about Aperture 'fraid, I'm a PC guy.
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Thank you Mike.
I'm going to have to find myself a PC with a RAW reader installed. One or two stops would have been acceptable, even expected ... as the light was very low and I was already shooting at very low speeds, 15th, 10th. So I was expecting to have to bring some of the shots back up ... but on the camera they look like they are sometimes maybe a 1/2 stop or a single stop down, no more. Most look very close to bang on.
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... Are you on a Mac?...
Yes, but that should not make any difference.
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I'll try Lightroom tomorrow. I've very curious to see if that still only needs a 2 stop adjustment - could be Adobe is reading it differently than Aperture. Actually, I popped it into my brother's Photoshop several weeks ago, and it only took a bit of adjusting. But I've got several hundred stills to tweak. And I do Aperture in my sleep. I wish Mac would stop killing off apps I've invested a lot of time mastering.
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Thank you Mike.
I'm going to have to find myself a PC with a RAW reader installed. One or two stops would have been acceptable, even expected ... as the light was very low and I was already shooting at very low speeds, 15th, 10th. So I was expecting to have to bring some of the shots back up ... but on the camera they look like they are sometimes maybe a 1/2 stop or a single stop down, no more. Most look very close to bang on.
I just opened the two images in RawTherapee (free, available on Mac, Windows and Linux), the RAW file seems to be just over 2 stops under exposed.
Can you shoot some evenly lit scenes with the camera set to shoot RAW+JPG, and provide links? Perhaps shoot the scene in program mode, aperture priority and manual, and check the exposure values the camera is choosing.
The other thing to do (forgive me if I missed that you've already done this), is to reset the camera back to factory defaults (make a note of your settings first!), then shoot RAW+JPG again of a similar scene.
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I just opened the two images in RawTherapee (free, available on Mac, Windows and Linux), the RAW file seems to be just over 2 stops under exposed.
Can you shoot some evenly lit scenes with the camera set to shoot RAW+JPG, and provide links? Perhaps shoot the scene in program mode, aperture priority and manual, and check the exposure values the camera is choosing.
The other thing to do (forgive me if I missed that you've already done this), is to reset the camera back to factory defaults (make a note of your settings first!), then shoot RAW+JPG again of a similar scene.
Okay. Will do this weekend xocet. Thank you for the suggestions. If I wasn't trying to finish a film on a deadline I'd be all over this immediately. Will report back with samples by Monday.
All the best, Ben
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I just opened the two images in RawTherapee (free, available on Mac, Windows and Linux), the RAW file seems to be just over 2 stops under exposed.
Mmmm. I just downloaded and tried RawTherapee. It opened the RAW file (the one we've been looking at) and it looks, actually, about a stop too light. Wow. I wonder if RawTherapee is doing some kind of auto-compensation when it opens the file? I zoom in and the detail is clean, the same grain and texture as I'm getting when I zoom in on the camera, though about a stop or so lighter than what I see in the camera. The mystery deepens. Xocet, I'll read up in the RawTherapee manual, see if it does batching in and out ... must get to work on this film. Very helpful, thank you kindly. Will report back after a bit more experimenting.
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Yes. The RawTherapee is auto-compensating when it loads the pic. So the original may, in fact, be dark. I'll do all the tests you recommend.
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Some ideas: If the picture style for the in camera jpgs is contrasty & well saturated the displayed histogram during/after the shot might show overexposure even if there is none as the histrogram is based on the embedded jpg. This can easily lead to an underexposure of 1-3 EV if one is working with the raws afterwards.
About the +5 EV exposure compensation: Are you using any import-profile while loading the files into lightroom? Maybe some negative exposure compensation is stored in the profile and adds up to the -2EV other users are seeing.
Best thing would be to use spot-metering and take a picture of a i.e. white piece of paper without any exposure compensation. The paper should be neutral grey on the picture afterwards
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Thank you Borgefjell,
I'm going to look at what you are suggesting here. I also just got the latest Panasonic GH4 firmware update. I seem to remember that I never had this 'dark shot' problem BEFORE I did the last update (2.00), only after.
Maybe the new firmware will make a difference. If not I will certainly try your suggestions.
Thank you most kindly,
Ben
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Late to this but this thought comes to me having seen similar on my old Fuji X100.
Do you have some sort of "dynamic range improver" switched on? Fuji sneakily changes the true ISO from that indicated to "extend" dynamic range in the JPEGs.
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Hi Beau,
Yeah. I was looking, unsuccessfully, for something like that. Couldn't find anything. But. Panasonic came up with a firmware update. Which I installed. And I think the issue has been resolved. I seem to be getting the exposure I see on the camera LCD screen ... in the computer when I import the stills. There is still a slight difference, a stop or so, between the jpg versions and the RAW versions. Darker on the RAW.
So maybe it had something to do with the previous firmware update. When I first got the camera there was no issue at all, regarding exposures.
All the best,
Ben
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Good to hear the problem seems to be solved! happy shooting :)
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Late to this but this thought comes to me having seen similar on my old Fuji X100.
Do you have some sort of "dynamic range improver" switched on? Fuji sneakily changes the true ISO from that indicated to "extend" dynamic range in the JPEGs.
iDynamic?
Edmund