EM1.2 histogram

ThomD

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The histogram doesn't display what I expect. In ESP mode, with with the shutter speed set way too fast, the histogram doesn't show that the image will be under exposed. The aperture indicator is flashing, showing that it can't open wide enough, but the histogram appears to be showing the values for the LCD display, not what the captured image is going to be. When I play back the image (in camera), that histogram is correct.

Does anyone have any suggestions for a setting I'm missing?
 

David A

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On the E-M1 there's a setting in the Fears menu, menu D, called "Live View Boost". Make sure it's set to "Off". You probably have it set to "On". The Histogram is taken from the JPEG data displayed on the screen and in the EVF and if Live View Boost is set to On, then the screen/EVF do not reflect changes you make to exposure and since the display doesn't change, the data the histogram uses doesn't change and if the data the histogram uses doesn't change, then the histogram doesn't change.

Turning Live View Boost off means that the image displayed on the screen and in the viewfinder will look washed out if you are overexposing and overly dark if you are underexposing. Turning Live View Boost on means the image displayed always looks correctly exposed so it's easy to see what you're shooting but adjusting exposure compensation has no effect at all on the way the image is displayed.
 
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On the E-M1 there's a setting in the Fears menu, menu D, called "Live View Boost". Make sure it's set to "Off". You probably have it set to "On". The Histogram is taken from the JPEG data displayed on the screen and in the EVF and if Live View Boost is set to On, then the screen/EVF do not reflect changes you make to exposure and since the display doesn't change, the data the histogram uses doesn't change and if the data the histogram uses doesn't change, then the histogram doesn't change.

Turning Live View Boost off means that the image displayed on the screen and in the viewfinder will look washed out if you are overexposing and overly dark if you are underexposing. Turning Live View Boost on means the image displayed always looks correctly exposed so it's easy to see what you're shooting but adjusting exposure compensation has no effect at all on the way the image is displayed.
"fears menu"? Freudian slip?
 

ThomD

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On the E-M1 there's a setting in the Fears menu, menu D, called "Live View Boost". Make sure it's set to "Off". You probably have it set to "On". The Histogram is taken from the JPEG data displayed on the screen and in the EVF and if Live View Boost is set to On, then the screen/EVF do not reflect changes you make to exposure and since the display doesn't change, the data the histogram uses doesn't change and if the data the histogram uses doesn't change, then the histogram doesn't change.

Turning Live View Boost off means that the image displayed on the screen and in the viewfinder will look washed out if you are overexposing and overly dark if you are underexposing. Turning Live View Boost on means the image displayed always looks correctly exposed so it's easy to see what you're shooting but adjusting exposure compensation has no effect at all on the way the image is displayed.
Thanks for the suggestion. As far as I can tell, Live Boost only shows the impact of exposure compensation. If you are just flat out under exposed (because the SS is too fast), live boost and the historogram are of no help.

From a functional point of view, I'd rather the histogram show me what is going to happen when I press the shutter, regardless of live boost or exposure comp.
 

David A

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Thanks for the suggestion. As far as I can tell, Live Boost only shows the impact of exposure compensation. If you are just flat out under exposed (because the SS is too fast), live boost and the historogram are of no help.

From a functional point of view, I'd rather the histogram show me what is going to happen when I press the shutter, regardless of live boost or exposure comp.
I'd suggest you check the Live View Boost setting whatever you think. It will only take you a couple of seconds to check it and to see whether it's on or off, and if it's on it will only take you a few seconds to turn it off and see whether that solves your problem. You have nothing to lose.

Live View Boost does not show the impact of exposure compensation. Turning off Live View Boost allows the screen/viewfinder to show the impact of exposure compensation, and also to show the effects of exposure changes so if you're underexposed It isn't only the effects of exposure compensation which it allows you to see.

Also I get that you'd rather the histogram show you what is going to happen when you press the shutter, regardless of the Live View Boost setting, but the histogram is derived from the image shown on the screen/viewfinder and as I said, if you set Live View Boost to On so that it does not show the effect of exposure changes, then the histogram is not going to change because the image being displayed on the screen/viewfinder isn't changing. When you asked the question in the initial post, you said " the histogram appears to be showing the values for the LCD display, not what the captured image is going to be. When I play back the image (in camera), that histogram is correct." You are totally correct. When you're shooting, the histogram shows you the values being displayed on the LCD display, and when you play back the image after you've taken the photo, the histogram takes its values from the image you captured. With Live View Boost on, the LCD display is not showing you the image that will be captured, it's showing you a much brighter image than the underexposed image you will capture if your exposure settings are going to result in underexposure. The way to get the histogram to show the result you will get from the exposure you have set, including any exposure compensation, is to turn Live View Boost off.

And I'll also repeat what I originally said. The histogram shows colour information and the RAW data captured by the sensor does not include any colour information so you cannot get a histogram from it. The sensor has a Bayer Array filter in front of it, half of the pixels capture light through a green filter and record the brightness value for light coming through that filter, a quarter of the pixels capture light through a red filter and a quarter through a blue filter, and those pixels also record the brightness value for light coming through those filters, but the three filters (red, green, and blue) aren't equally strong and none of them capture the correct brightness value for the colour that pixel will display in the eventual image after the demosaicing and other processes which have to be done in order for you to see an image you will recognise as looking like the scene you're shooting. The camera applies those processes to the data from the sensor in order to display an image of the scene you're shooting on the LCD screen and in the viewfinder, and the histogram displays the image data after those processes have been done. The histogram will only change when there is a change in the image being displayed and if you have Live View Boost turned on, the image being displayed is not going to change because you've disabled the ability of the LCD to adjust to any exposure changes you make and show the effect of those changes. The image being displayed with Live View Boost on is not the image which will be captured, the image displayed with Live View Boost off is the image which will be captured and it will show the results of any exposure changes you make as you make them, so the histogram will change as you make those changes.

Once again, TRY IT!!! You have nothing to lose and it should solve your problem. Cameras don't always work the way you think they should work, or the way you want them to work. They work the way their designers designed them to work, whether that way is what you want or not. If you want the histogram to show the results of your exposure settings and any changes you make to them, the only way to get it to do that is to turn Live View Boost off.
 

Klorenzo

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I think the histogram is updated up to three/four stops of difference from the camera metering, actual number depending on the scene, about at the same time when things start to blink.

It is not common to find situations where this is an actual problem, but can be confusing. You need a situation where the metering is off by more than three stops from your intended exposure, scenes with high dynamic range (or user error).

Anyway, switching to a different kind of metering solves the problem, or using AEL, etc. Switching to Manual obviously does not help as this does not affect the metering. So for a landscape where you want to protect the highlights a quick way is to point the camera to the sky, press AEL, reframe and to use exposure compensation for fine tuning.

Another exception are really long exposures where the histogram and the preview stop to move earlier, around two EV of difference.
 
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ThomD

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I'd suggest you check the Live View Boost setting whatever you think. It will only take you a couple of seconds to check it and to see whether it's on or off, and if it's on it will only take you a few seconds to turn it off and see whether that solves your problem. You have nothing to lose.
Sorry, meant to say that the shift (left and right) histogram in S only shows the impact of EC. Again, if you have too high a shutter speed, it is not useful as a warning. And that if live boost is on it does not show the impact of EC. in M mode if LVB is off, then what you see is what you get. Regardless, I'd still rather have the histogram read the data from earlier in the processing cycle.
 

Cederic

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I did some testing. In manual the histogram ignores reality with Live View Boost (Manual) on. With Live View Boost (Manual) off it does show that there'll be clipping but still seems to think some detail will be captured - even at f22 and 1/8000 second indoors shooting in the shadows left by a table lamp.

In Shutter Priority at 1/32000s and f2.8 the photograph is still black except for the noise artifacts. The histogram still hoiwever merrily tells me that the photograph is beautifully balanced, irrespective of Live View Boost settings. There isn't a Live View Boost (Shutter Priority) setting to disable.

In Program and Aperture Priority modes the camera's too sensible to let me set it out of range.

This isn't a metering issue, this is a histogram failing to represent the light that will be captured issue. I share ThomD's confusion here.

Note that the four histograms you can get on the image review screen are perfectly fine. So unless you're shooting action or other things that might move there is at least an opportunity to review and correct - but shooting shutter priority often means you are photographs things that move.
 

Klorenzo

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I did some testing. In manual the histogram ignores reality with Live View Boost (Manual) on. With Live View Boost (Manual) off it does show that there'll be clipping but still seems to think some detail will be captured - even at f22 and 1/8000 second indoors shooting in the shadows left by a table lamp.

In Shutter Priority at 1/32000s and f2.8 the photograph is still black except for the noise artifacts. The histogram still hoiwever merrily tells me that the photograph is beautifully balanced, irrespective of Live View Boost settings. There isn't a Live View Boost (Shutter Priority) setting to disable.
Was there anything blinking while you took these shots?
 

David A

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Sorry, meant to say that the shift (left and right) histogram in S only shows the impact of EC. Again, if you have too high a shutter speed, it is not useful as a warning. And that if live boost is on it does not show the impact of EC. in M mode if LVB is off, then what you see is what you get. Regardless, I'd still rather have the histogram read the data from earlier in the processing cycle.
If Boost is on, the histogram does not show the effect of exposure changes. Exposure compensation is an exposure change, but it is not the only exposure change you can make. If your aperture setting in A mode or shutter speed setting in S mode is going to result in extreme under or over exposure, you aren't going to accurately see the effects of that under or overexposure on the screen/viewfinder and the image being displayed is not going to change when you adjust your aperture/shutter speed if you have Live View Boost on. As I repeatedly have said, the histogram is derived from the image being displayed and if you want the histogram to show the effect of exposure changes of any kind, the image being displayed has to change so you have to turn Live View Boost off.

And, as I said, I appreciate that you'd rather have the histogram read the data from earlier in the processing cycle. The simple fact is that it doesn't so we have to live with that. As far as I know, no camera manufacturer offers a camera with a histogram created from data at an earlier stage in the cycle. If you're going to use a particular camera, then you have to work with it and the way it operates. That's true for every camera, not just the E-M1 MkII.


I did some testing. In manual the histogram ignores reality with Live View Boost (Manual) on. With Live View Boost (Manual) off it does show that there'll be clipping but still seems to think some detail will be captured - even at f22 and 1/8000 second indoors shooting in the shadows left by a table lamp.

In Shutter Priority at 1/32000s and f2.8 the photograph is still black except for the noise artifacts. The histogram still hoiwever merrily tells me that the photograph is beautifully balanced, irrespective of Live View Boost settings. There isn't a Live View Boost (Shutter Priority) setting to disable.

In Program and Aperture Priority modes the camera's too sensible to let me set it out of range.

This isn't a metering issue, this is a histogram failing to represent the light that will be captured issue. I share ThomD's confusion here.

Note that the four histograms you can get on the image review screen are perfectly fine. So unless you're shooting action or other things that might move there is at least an opportunity to review and correct - but shooting shutter priority often means you are photographs things that move.
As I have repeatedly said, the histogram is derived from the JPEG data the camera displays on the screen/viewfinder, not from the RAW sensor data. If you have Live View Boost on, the image displayed on the screen/viewfinder is not the same as the image which is going to be captured, and the image displayed does not change with exposure setting changes. Whatever image is displayed on the screen/viewfinder is the image the histogram is derived from. The histogram can "represent the light that will be captured" but for it to do that, the image being displayed on the screen/viewfinder has to represent the light that will be captured and it can only do that if Live View Boost is set to off.

In S priority on my E-M1 MkI (I don't have a MkII), there are 4 options in the Live View Boost setting menu. They are Manual Shooting, Bulb/Time, Live Composite, and Others. Others covers everything except the preceding 3 special case options so it applies to S priority and also to A priority plus any other modes not specifically listed in the menu.

The image review screen displays images after capture and the histograms are for the image that you captured. Of course they're fine because you're looking at a histogram for the image you captured and the image on the screen/viewfinder is the image which was captured. Live View Boost isn't used during image review because the whole point of image review is to let you see what you actually got.



The bottom line is that the histogram will show you info for the photo you're going to capture if you have Live View Boost off. If you have Live View Boost on, the histogram shows you the light distribution for the image being displayed on the screen/viewfinder and that is not the image which will be captured. If you are in image review, Live View Boost is inoperative and the image that the camera shows you is the one which you actually captured. The histogram displayed if for that captured image and is accurate for the captured image.

This is simply the way these cameras work. It does not matter whether you like it or not, whether you think it is intuitive or not, or whether you have any other opinion about whether cameras should or should not work this way. It is the way these cameras work and we can't change that. If we want the histogram to reflect the image we are going to capture, and to respond to exposure changes as we make them, we have no other option but to turn Live View Boost off. Complaining that it shouldn't work that way, or that you don't like it, or that it isn't intuitive aren't going to change the fact that the camera works this way. You can take that up with Olympus but the fact is that if the histogram is going to reflect the image that you are going to capture, it has to be drawn from data derived after some image processing has been applied to the RAW sensor data and there is no way around that. The RAW sensor data simply isn't suitable for deriving a histogram which shows colour channel information because colour channel information is not present in the RAW data from the sensor, it is generated later after some image processing steps which are necessary if the camera is going to show you a colour image of your scene with a reasonably accurate representation of the scene you're shooting. The camera has to do those steps to generate an image for the screen/viewfinder and the data for the histogram is taken from the image being displayed on the screen/viewfinder.

If you want the histogram to reflect the image that will be captured, the camera would have to generate that image, but that image is going to be different from the image being generated for display if you have Live View Boost on, so the camera would need to be processing 2 separate versions of the image simultaneously, one for the histogram and one for display on the screen/viewfinder, if you want to view the image on the screen/viewfinder with Live View Boost while having the histogram reflect the image that will be captured. The camera only has the capability to process one version of the data at a time and that means that whichever version of the image that you ask it to generate is the one from which the histogram is derived. Your Live View Boost setting is the setting you use to tell the camera which version of the image to process.
 

Cederic

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If you have Live View Boost on, the image displayed on the screen/viewfinder is not the same as the image which is going to be captured, and the image displayed does not change with exposure setting changes. Whatever image is displayed on the screen/viewfinder is the image the histogram is derived from.
Yes, you keep saying this. Which is why I made it clear that in my tests I had Live View Boost turned off. Menu D2, Live View Boost:
- Manual : Off
- Bulb/Time : On2 (because there is no off setting available)
- Live Composite : Off
- Others : Off

Despite this, as ThomD noted, the histogram in shutter priority mode shows the balance of the image on screen, not the image that will be captured. This confuses me as it makes the histogram worthless, and so I share ThomD's curiousity whether there is a setting that can enable the histogram to act the same way as every other camera I've owned that has had one.

Klorenzo, yes, the aperture was flashing. That's certainly one way to understand that elements of the image will be poorly exposed but does not compensate for a working histogram.
 

alex g

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It is a little mysterious, I agree, but I think it makes more sense if you remember that when you put the camera into any of the auto-exposure modes, you're asking it to meter and expose "correctly" given the value of the parameters you set (aperture or shutter speed, depending on which mode you're in, and exposure compensation) and the limits of the parameters which it controls itself (aperture, shutter speed and/or ISO sensitivity). So long as the values of the latter remain within the physical limits of the camera and lens (maximum/minimum aperture, fastest/slowest shutter speed, upper/lower ISO limit) the metering system is happy and the histogram will reflect the exposure of the captured jpg. However, as soon as it comes up against a hard limit (e.g. maximum aperture of the lens), the camera is no longer capable of fulfilling its brief — that of correctly exposing the image. At which point, it alerts you to the fact by flashing one of the parameter fields in the EVF. It's telling you that you're now looking at bogus information. The solution, therefore, is to adjust exposure compensation in such a way as to make the exposure equation legal again, whereupon the histogram will once again be accurate.

Does that help at all?
 

David A

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Yes, you keep saying this. Which is why I made it clear that in my tests I had Live View Boost turned off. Menu D2, Live View Boost:
- Manual : Off
- Bulb/Time : On2 (because there is no off setting available)
- Live Composite : Off
- Others : Off

Despite this, as ThomD noted, the histogram in shutter priority mode shows the balance of the image on screen, not the image that will be captured. This confuses me as it makes the histogram worthless, and so I share ThomD's curiousity whether there is a setting that can enable the histogram to act the same way as every other camera I've owned that has had one.

Klorenzo, yes, the aperture was flashing. That's certainly one way to understand that elements of the image will be poorly exposed but does not compensate for a working histogram.
1- My E-M1 MkI has an off setting for Bulb/Time and I don't see why the MkII would not. I don't have a MkII to check that.

2- ThomD may have noted that the histogram in shutter priority mode shows the balance of the image on screen but if you go back and read what I have continually said, I keep repeating that the histogram always shows the balance of the image on the screen. If the image on the screen is also the image that is going to be captured, i.e. if Live View Boost is off, then the histogram will also show the balance of the image to be captured. The histogram isn't worthless if you have the screen/viewfinder set to show the image as it will be captured. In the Live View Boost menu on my E-M1, it provides the following explanation of each setting (the bolding is mine to emphasise the point I keep making):

Off - Live View brightness will reflect exposure settings. Brightness of image seen is the same as that of the final image.

On1 - Live View brightness will not reflect exposure settings and will be adjusted for optimal viewing. Brightness of final image will differ.

On2 - Live View brightness will not reflect exposure settings and will be adjusted for optimal viewing w/ slow frame rate for dark areas. Brightness of final image will differ.


If the image brightness reflects exposure settings and the brightness of the image is the same as that of the final image, then the histogram will reflect the image that is captured because it is taken from the image displayed. If the image brightness does nor reflect exposure settings and the brightness of the image is going to differ from the final image, the histogram is not going to update for exposure compensation and other exposure changes.

We can continue going round and round like this and getting nowhere but what you and ThomD need to face is that ThomD asked a question and I've given the only answer that has been provided. No one has said I'm wrong, or offered an alternative answer. That doesn't mean I'm right but we've been beating this around the bush now for a couple of days and there has been plenty of opportunity for someone with a different answer to join in, say I'm wrong, and give a different answer. I can't give you a different answer and no one else here is giving you a different answer so continuing on with this isn't looking like it's going to give you what you want. It's up to you whether you believe that's because no one here knows enough to be able to give you the right answer or because the only answer you've been given here is the right answer and there's no other answer possible. Those are the only 2 explanations for the lack of alternative responses here.
 

alex g

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1- My E-M1 MkI has an off setting for Bulb/Time and I don't see why the MkII would not. I don't have a MkII to check that.
For reference, it doesn't. There are actually quite a few subtle changes to the way some of the systems are structured. Live View Boost is one of those systems — in the new camera there are more options for customising Live View Boost behaviour than there are in its predecessor.
 

Cederic

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i.e. if Live View Boost is off, then the histogram will also show the balance of the image to be captured.
Thank you for trying to help, but as ThomD stated and my testing confirms, if Live View Boost is off, then the histogram will (in shutter priority mode) NOT show the balance of the image to be captured.

Perhaps this is a new bug introduced in the Mark II that you're fortunate enough not to have encountered in the original.
 

alex g

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As a post script to this discussion, I've noticed what does appear to be something of a metering/histogram/LiveView anomaly in the E-M1.2.

With the camera in aperture priority mode and the histogram display turned on, the brightness of the live view and the shape of the histogram will change whenever the AF is activated (e.g. the shutter button is half pressed). The behaviour is more noticable with C-AF, because the AF is, by definition, active for as long as you keep the button half-pressed. The jump in levels depends on the content of the scene and the brightness of the subject beneath the exposure target. I've found the most obvious effects are seen when aiming at a small, relatively light-coloured object against a predominantly dark background. While the AF is inactive, the rightmost end of the histogram might be at, say, 80%, but when the shutter button is half-pressed, it may jump up to as much as 100%, sometimes with a tall red bar indicating that it's heavily clipped. At the same time, the highlights in the live view will be blown out.

Fortunately, this behaviour is not reflected by the actual exposed image, which instead reflects the brightness and histogram values displayed before the AF is activated, as it should. It's almost as if Live View Boost is being turned on while AF is active, despite it being disabled in the menu settings. It's curious: neither the original E-M1 nor the E-M5.2 exhibit this behaviour, so it's either a bug, a new "feature" or perhaps even an inherent drawback of the new focusing system. It doesn't affect the final image, but it's nonetheless disconcerting and a little distracting. I've emailed Olympus Japan to see what they have to say about it.
 

KBeezie

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You would think after several years of existance that the histogram should be based on actual exposure and not the exposure of the "Live Boost" on the screen which is not what is captured to the file. (if the meter can tell you that it's -3 or +3 EV while the live view appears normal, then it shouldn't be that hard to calculate a histogram based off actual data).
 

Giiba

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Not to sidetrack the discussion, but I've been following along with this as I too have found the histogram kinda useless.

I'm wondering what the advantage of the histogram is over the highlights/shadows live readout? I find the later the single best feature of mirrorless cameras and way more useful than the histogram. Why not juat use that instead and forget the strange histogram?
 
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