GH2 shooting underexposed?
- Thread starter Azmyth
- Start date
Seems like darkening up a shot in post is one of the easiest things one could do, but no harm in getting it near where you want it whilst shooting. Shooting underexposed might produce unwanted noise and other potential problems that you wouldn't have if you exposed it just a bit.
Jaime Valles
Veteran
Yeah, don't underexpose unless you have no choice.
woodcarver
Well-known member
In the days when Fincher was shooting on film, he'd flood scenes with light and then pull process the film to get the dark, underexposed look without all the grain. Usually "dark" shots are really high contrast shots--where one part of the image reads like it has been exposed properly and the rest falls off dramatically. Getting this look without underexposure problems usually means lighting with high contrast but within the DR of the sensor then dropping it down in post.
Aki_Hartikainen
Carbonite Member
According to Michael Reichmann http://www.luminous-landscape.com/tutorials/understanding-series/u-raw-files.shtml for JPG files only 5 f-stops of latitude exists. Amount of different values for each f-stop become progressively less when coming down the scale. Hence giving more exposure while filming will yield a better quality image, because more possible values can be used when capturing. When exposure is lowered in post, the values become closer to each other minimizing posterization.
Shooter
Veteran
"exposure" for "dark shots" is done with lighting...not with the camera.
General rule still applies though. Protect your shadows and protect your highlights. That gives one room to move in post.
BTW- there should be no noise issues (or grain issue) with "under exposure"...unless you try and regain the detail that was not there.
General rule still applies though. Protect your shadows and protect your highlights. That gives one room to move in post.
BTW- there should be no noise issues (or grain issue) with "under exposure"...unless you try and regain the detail that was not there.
Those shots look pretty good. Nice soft lighting. I would say that the approach of exposing a bit hotter and then bringing it down in post is a good idea. Maybe by only 1/3 to 2/3 of a stop however. This approach is/was done by film guys a lot. They'd overexpose every shot by 1/3 of a stop and pull it back down in the processing to get darker, richer blacks. However, everybody works differently. Creativity has no rules. So if you can get the shot to look good by nailing it in camera slightly underexposed, then go for it. Lots of cinematographers like a "thin negative" and underexpose their scenes.
I think the GH2 can handle underexposure a LOT better than the GH1. The GH1 had a weird issue in the shadows just below middle gray. If your skin tones settled there, they got this horrible color noise. So I HAD to expose hotter and then "print down" with the GH1. Not so much an issue with the GH2 thankfully.
I think the GH2 can handle underexposure a LOT better than the GH1. The GH1 had a weird issue in the shadows just below middle gray. If your skin tones settled there, they got this horrible color noise. So I HAD to expose hotter and then "print down" with the GH1. Not so much an issue with the GH2 thankfully.
DPStewart
Veteran
Here's the shots in question. They were shot at like 800 iso.. with the meter showing about 2-3 stops underexposed.
Good example of underexposure artifacts looking cool.
The first still is great, Az. If you're going for an underexposed look and you aren't worried about getting any specific detail back then shooting like that is fine.
If you want a little more flexibility try putting a more exposed image to the card. Still, looks good to me, man.
If you want a little more flexibility try putting a more exposed image to the card. Still, looks good to me, man.
Aki_Hartikainen
Carbonite Member
Was there any additional exposure to spare in the lens or more light wattage available on location or was everything already in use for this exposure? I'm interested, because it's once again the blue channel that looks the most coarse. If any exposure was available, it would be possible to use the blue lens filter (0.5 f-stop reduction) to obtain more blue channel values. This will help later in post.
Aki_Hartikainen
Carbonite Member
I have demonstrated the blue light technique here, it indeed works: http://www.dvxuser.com/V6/showthrea...hink-I-want-a-GH2-but-I-have-a-question/page2 (at the bottom of the page).
For flatter and less posterized source image one full f-stop more exposure was required. This means doubling the lighting wattage on location, so not always possible. Even flatter and less posterized image would have resulted from exposing even more, and later lowering exposure in post. In Adobe programs there is a filter Exposure, which tries to accurately change image brightness as if exposure was altered in the camera or on location.
For flatter and less posterized source image one full f-stop more exposure was required. This means doubling the lighting wattage on location, so not always possible. Even flatter and less posterized image would have resulted from exposing even more, and later lowering exposure in post. In Adobe programs there is a filter Exposure, which tries to accurately change image brightness as if exposure was altered in the camera or on location.
DPStewart
Veteran
I read your post - very interesting techniques.
I was also very interested in the filter technique for the RED band. Very effective. Normally I HATE digital video reds.
j1clark@ucsd.edu
Veteran
Here's the shots in question. They were shot at like 800 iso.. with the meter showing about 2-3 stops underexposed.
I'll weigh in on this... for me, both of the example images are way 'under exposed'. For me the problem lies with the fact that the 'dark' areas go too dark, and result in potential areas of 'noise', which distracts from the rest of the image.
The woman's left side of the face, is essentially a black blotch. Since I don't know the context of this shot, this may be a momentary couple of frames, or there could be a storywise significant pause. If the shot is a couple of frames, then moving 'into the light', well, fine. But if it was some sort of poignant pause, I think the shot is too dark.
I would have exposed for higher values, then adjusted 'curves' to bring the contrast ratio to the point of the 'mood' desired, while still maintaining detail in the shadow side.
One of the things I've been working with, with my GH-1, is how much futzing around with the contrast I can do, before certain effects show up, banding, noise in shadows, etc. So, I don't think it is an easy process, to get more 'moody' shots.
Here's an example from "Woman in Black"(2012), and I'm presuming it has been processed, and perhaps the 'jpeg' doesn't really reflect the original in contrast, but some elements still are 'visible', namely higher value on the lit side of the face, and a 'hint' of the eye on the shadow side. (I tried to find more 'interior' type shots but alas the Internet failed me on this one...).
As a note, I would like to mention that typically one does not 'over expose' or 'under expose'... one 'properly exposes' for the final image one wants... So, using some 'zone system' type terminology, if I want a 'dark/mood' shot, I 'place the 'white' skin tone on Zone V', normally 'white' people's skin tone is on VI, but I've 'placed it lower' for the mood.
The difficulty then is not to have all the shadows drop off into nothingness, and so, some light will be need to keep the 'shadow' on the person's face, to perhaps Zone IV...
In other terms, the shadow side is one stop down from whereever the lit side is... Normally one can 'stand' a 2 stop difference, but that requires the lit side to be at Zone VI... that sort of explains the lighting on Daniel Radcliffe's face. The dark background and 'interior' keys the viewer to 'this is a dark place'... and the window light still motivates 'oh, that's why his face is still visible'...
If the lit side starts at Zone V, two stops down will begin to be in the 'mud' of darkness...
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Azmyth
Veteran
Here's the shots in question. They were shot at like 800 iso.. with the meter showing about 2-3 stops underexposed.
I'll weigh in on this... for me, both of the example images are way 'under exposed'. For me the problem lies with the fact that the 'dark' areas go too dark, and result in potential areas of 'noise', which distracts from the rest of the image.
The woman's left side of the face, is essentially a black blotch. Since I don't know the context of this shot, this may be a momentary couple of frames, or there could be a storywise significant pause. If the shot is a couple of frames, then moving 'into the light', well, fine. But if it was some sort of poignant pause, I think the shot is too dark.
I would have exposed for higher values, then adjusted 'curves' to bring the contrast ratio to the point of the 'mood' desired, while still maintaining detail in the shadow side.
One of the things I've been working with, with my GH-1, is how much futzing around with the contrast I can do, before certain effects show up, banding, noise in shadows, etc. So, I don't think it is an easy process, to get more 'moody' shots.
Here's an example from "Woman in Black"(2012), and I'm presuming it has been processed, and perhaps the 'jpeg' doesn't really reflect the original in contrast, but some elements still are 'visible', namely higher value on the lit side of the face, and a 'hint' of the eye on the shadow side. (I tried to find more 'interior' type shots but alas the Internet failed me on this one...).
As a note, I would like to mention that typically one does not 'over expose' or 'under expose'... one 'properly exposes' for the final image one wants... So, using some 'zone system' type terminology, if I want a 'dark/mood' shot, I 'place the 'white' skin tone on Zone V', normally 'white' people's skin tone is on VI, but I've 'placed it lower' for the mood.
The difficulty then is not to have all the shadows drop off into nothingness, and so, some light will be need to keep the 'shadow' on the person's face, to perhaps Zone IV...
In other terms, the shadow side is one stop down from whereever the lit side is... Normally one can 'stand' a 2 stop difference, but that requires the lit side to be at Zone VI... that sort of explains the lighting on Daniel Radcliffe's face. The dark background and 'interior' keys the viewer to 'this is a dark place'... and the window light still motivates 'oh, that's why his face is still visible'...
If the lit side starts at Zone V, two stops down will begin to be in the 'mud' of darkness...
I'm all sorts of confused by this lol.
j1clark@ucsd.edu
Veteran
Should I try to make it worse by explaining...
Ok... maybe I will.
There's some terminology. So, this is how I would uses some of the 'terms'.
Proper Exposure -- a camera setting that yields the image I had in mind.
Under Exposure -- a camera setting that I had to use, because for the circumstances, there wasn't enough light, but I had to get the shot, no matter what.
Over Exposure -- a camera setting that I had to use, because for the circumstances, there was too much light, but I had to get the shot, no mater what.
So, I would not call a 'dark mood' shot 'under exposed', unless the description above applied.
I would call such a shot 'proper exposure' for the resulting image. I decided to have the scene dark, I decided to have the skin tone of the actress 'dark', etc.
Determining the 'proper exposure' is based on the technology of image formation. In the case of film, one can expose the negative to give a certain density that
will result in the print having a certain set of values. This is true whether the 'print' is paper for a still, or thousands of 'stills' on motion picture print film.
For 'digital film', the priorities may change but the goal remains the same. What 'output values' does one want to see in the projected image. (or still from the digital media...).
To understand how to get that 'proper exposure', then requires one to understand 'what is a meter calibrated to yield'. Most meters are calibrated to yield an exposure that places a standard card at a certain value. The phrase '18% grey card' is often used. Most fair skinned, especially northern European people, have a reflectivity that is about 2x an 18% grey card, or about 1 stop different. So, when one gets a meter reading from a fair skinned person's face, one has to 'adjust' the reading by opening up one stop.
So, if one has a 'grey card' for metering, one need not make such an adjustment...
For a 'dark mood' image, the idea would be to set the fair skinned person 'one stop lower' than usual, to reflect the dark mood...
This would work if the lighting is 'flat' across the face. However, most dramatic situations call for a 1 stop difference, or even 2 stop difference, which may cause trouble.
The trouble is that if the 'bright side' of the face is at 'middle gray', that is '18% reflectivity', the '2 stop difference' will set the image 'darkness' to be about 4-5%... which may be so dark that the camera does not 'record' the detail. This is true for film or digital imagine.
The example I give of Daniel Radcliffe in "Woman in Black", shows how that cinematographer overcame this problem. The 'bright side' of Radcliffe's face is at approximately 'normal' values, that is 1 stop above middle grey. (if it were a B&W image...). The shadow side is about 1 stop below middle grey... yielding the dark mood of the shot, with a 2 stop difference between high to low side of the face.
Further the back ground is dark, and could be dropping down into near 3-4 stops lower than Radcilffe's face, which is for most viewers the 'key' element to interpret the scene... he's in a 'dark room' and 'something bad will happen'.
What this yields is a face that is entirely readable, yet does not break the dark mood of the shot. There's no 'lunar landscape' effect, which may be useful at some point, but I don't think your shot was trying for that.
Alternatively... if you did want the face to be 'dark', then you need to 'flatten' the light to make less of a contrast ratio between light and dark. Often in this sort of situation, there's a brighter 'rim' light, perhaps in the hair, and the rest of the face goes rather dark, but nothing below 'one stop lower' than the 'middle grey' card.
Does that make things more clear?
As a potentially confusing post script... the value of Mediterranean and darker complexion is 18% grey, or less, so the difficulty there with 'dark mood' is the fact that if you make the face, darker, you are already 'pretty dark', and quickly loose detail in the face. So, with this type of complexion, one needs to light for 'contours' to show facial features, while still maintaining the dark mood.
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