K1 weird histogram in LV mode

biz-engineer · 07-01-2018, 10:39 AM

Today I was outdoors in nature, and when I wanted to take some photographs in live view mode using Av, Tv and TAV, the histogram displayed on the LCD showed saturating highlights regardless of exposure settings, in order to check if I could move the histogram by changing the dialing down the exposure, the histogram stays the same (stuck at the right side) and after I took the shot I could verify that the histogram went on the left side and that the shot was underexposed. To me it looks like a bug. I tried again at home and the histogram of the shot is the same as the histogram of the live view display. Did anyone experience the same issue. For me, that raises the question of the usability of the histogram displayed in live view.

photoptimist · 07-01-2018, 11:10 AM

Any chance you were in spot-metering mode with something darkish in the center?

Not a Number · 07-01-2018, 11:13 AM - **6 Likes**

What happens in LV stays in LV.

biz-engineer · 07-01-2018, 11:33 AM

Originally posted by photoptimist

Any chance you were in spot-metering mode with something darkish in the center?

Well, I've tried spot metering, center weighted and matrix metering modes and it did not change the histogram being stuck on the right. Only thing I could think of was that most surrounding was green, so the quantity of green may have fool the metering.

**twilhelm** · 07-01-2018, 11:38 AM

So I understand you, the LV histogram shows it heavy right, but the actual photo is heavy left?

I ask because I’m wondering, if it’s a bright day, light coming into the viewfinder May skew the shot.

biz-engineer · 07-01-2018, 12:27 PM

Originally posted by twilhelm

So I understand you, the LV histogram shows it heavy right, but the actual photo is heavy left?

I ask because I’m wondering, if it’s a bright day, light coming into the viewfinder May skew the shot.

Yes the lv histogram hits the right and the shot is correctly exposed or even underexposed. In lv mode the exposure is metered via the image sensor directly, I don't think light through the ovf would change anything. I've obstructed the ovf with my hand and the lv histogram stayed stuck on the right.

stevebrot · 07-01-2018, 01:17 PM

I don't have a K-1 and generally ignore the LV histogram display, but dug out the K-3 to see what you are talking about.

Originally posted by biz-engineer

In lv mode the exposure is metered via the image sensor directly

The LV histogram is a strange beast. One might think that it is based on the actual sensor response, when near as I can tell, it actually reflects the state of the rear LCD display buffer which brightness and contrast is adjusted according to the exposure settings relative to the metered LV as well as the custom image settings for JPEG processing. It does a good job of predicting the actual JPEG capture histogram under most circumstances. I tried to reproduce your problem on the K-3, but could not unless ISO were set fairly high and/or EV were set low for a high LV scene (basically a scene requiring HDR to service both highlights and shadows).

Steve

**Mikesul** · 07-01-2018, 01:22 PM

I just played around with live view on my K-1 and the histogram is clearly not reliable. It was not stuck on the right and moved around as if responding to the exposure but the histogram of the photo was not at all like what the live view showed.

**twilhelm** · 07-01-2018, 01:25 PM

Since the brightness of the screen is adjusted to make it easier to view (ie brighter than the actual scene) is it possible this is what the histogram is in context with, as opposed to the actual recorded image? Just a shot in the dark.

**Mikesul** · 07-01-2018, 01:28 PM

Originally posted by twilhelm

Since the brightness of the screen is adjusted to make it easier to view (ie brighter than the actual scene) is it possible this is what the histogram is in context with, as opposed to the actual recorded image? Just a shot in the dark.

But that does not make it very useful. I did not have much time to check it so I willwork with it a little when I have some time. I do not use a tripod much so i never noticed anything before.

stevebrot · 07-01-2018, 02:19 PM

Originally posted by twilhelm

is it possible this is what the histogram is in context with, as opposed to the actual recorded image?

My thoughts are similar (see above) and follow the logic that since the actual recorded image does not yet exist, the screen emulation of that image might be the next best option. Just for kicks, check out the histogram with the cross-process custom image setting.

Originally posted by Mikesul

But that does not make it very useful.

It is useful in the sense that a simulation is what is available. (Live view differs from the EVF or rear display on a mirrorless in that the lens is not typically stopped down for metering, framing, and focus on a dSLR.) A histogram of the metered sectors might be even less useful, particularly for spot or center-weighted where most of the scene will not contribute. I am not much for basing exposure on histogram details or extremes after seeing the differences between in-camera, Affinity Photo, and Lightroom for identical JPEG. If the target is a gray card and the histogram is centered, the exposure is nominally "correct" based on the incident light. If using TTL matrix metering and either extreme of an otherwise balanced histogram is clipped, the button that should be pushed is to consider a bracketed exposure with intent to merge as HDR. ETTR sounds good* unless the shadows are clipped to save the highlights. (I generally use an actual test shot histogram to make these decisions.)

Steve

* To be honest, Expose To The Left (ETTL) is probably the appropriate term for the practice of preserving highlights by intentional underexposure with intent of attempting salvage of the shadows in post.

**Mikesul** · 07-01-2018, 02:35 PM

I am surprised because, although I rarely shoot with live view and have even more rarely checked the histogram before shooting, i have always assumed that the advice given to shoot with the histogram was universally applicable. I have consulted the histogram frequently after a shot where it has been very helpful. I guess I need to stop feeling guilty for not using it before a shot.

biz-engineer · 07-01-2018, 09:30 PM

Originally posted by stevebrot

One might think that it is based on the actual sensor response, when near as I can tell, it actually reflects the state of the rear LCD display buffer which brightness and contrast is adjusted according to the exposure settings relative to the metered LV as well as the custom image settings for JPEG processing.

I changed the LV outdoor settings to see if it would affect the centering of the LV histogram, and I can say that the outdoor settings did not affect the LV histogram. However, I noticed a strange thing: in live view mode, the scene is displayed continuously with the histogram being shifted in the right, but a centered LV histogram appeared for a very short time when I half pressed the shutter button for focusing, when focusing was done, the histogram went back to the left again. Could it be that the camera adjusts aperture and "shutter speed" (electronic only shutter) to adapt to lighting conditions in order to stream images such as in video mode and that in bright light the sensor is not able to achieve short enough capture time? If it was so, the image projected in LV would be blown out. I would rather think this case of histogram looks like a software bug.

stevebrot · 07-01-2018, 09:34 PM

Originally posted by biz-engineer

I changed the LV outdoor settings to see if it would affect the centering of the LV histogram, and I can say that the outdoor settings did not affect the LV histogram. However, I noticed a strange thing: in live view mode, the scene is displayed continuously with the histogram being shifted in the right, but a centered LV histogram appeared for a very short time when I half pressed the shutter button for focusing, when focusing was done, the histogram went back to the left again. Could it be that the camera adjusts aperture and "shutter speed" (electronic only shutter) to adapt to lighting conditions in order to stream images such as in video mode and that in bright light the sensor is not able to achieve short enough capture time? If it was so, the image projected in LV would be blown out. I would rather think this case of histogram looks like a software bug.

Change custom mode to cross-process and see what happens. The histogram looks to be driven from the LCD display buffer.

Steve

biz-engineer · 07-01-2018, 09:40 PM

Originally posted by stevebrot

Change custom mode to cross-process and see what happens. The histogram looks to be driven from the LCD display buffer.

Yes, the histogram is supposed to represent the JPEG setting, I've checked that the JPEG setting did not have exposure bias. I'll try what you say and investigate further, as it is good to know if there are some limitations when using the histogram in live view.

07-01-2018, 10:39 AM	#1
biz-engineer Pentaxian Join Date: Feb 2015 Photos: Gallery Posts: 12,231	K1 weird histogram in LV mode Today I was outdoors in nature, and when I wanted to take some photographs in live view mode using Av, Tv and TAV, the histogram displayed on the LCD showed saturating highlights regardless of exposure settings, in order to check if I could move the histogram by changing the dialing down the exposure, the histogram stays the same (stuck at the right side) and after I took the shot I could verify that the histogram went on the left side and that the shot was underexposed. To me it looks like a bug. I tried again at home and the histogram of the shot is the same as the histogram of the live view display. Did anyone experience the same issue. For me, that raises the question of the usability of the histogram displayed in live view.

07-01-2018, 02:19 PM	#11
stevebrot Otis Memorial Pentaxian Join Date: Mar 2007 Location: Vancouver (USA) Photos: Gallery \| Albums Posts: 42,007	Originally posted by twilhelm is it possible this is what the histogram is in context with, as opposed to the actual recorded image? My thoughts are similar (see above) and follow the logic that since the actual recorded image does not yet exist, the screen emulation of that image might be the next best option. Just for kicks, check out the histogram with the cross-process custom image setting. Originally posted by Mikesul But that does not make it very useful. It is useful in the sense that a simulation is what is available. (Live view differs from the EVF or rear display on a mirrorless in that the lens is not typically stopped down for metering, framing, and focus on a dSLR.) A histogram of the metered sectors might be even less useful, particularly for spot or center-weighted where most of the scene will not contribute. I am not much for basing exposure on histogram details or extremes after seeing the differences between in-camera, Affinity Photo, and Lightroom for identical JPEG. If the target is a gray card and the histogram is centered, the exposure is nominally "correct" based on the incident light. If using TTL matrix metering and either extreme of an otherwise balanced histogram is clipped, the button that should be pushed is to consider a bracketed exposure with intent to merge as HDR. ETTR sounds good* unless the shadows are clipped to save the highlights. (I generally use an actual test shot histogram to make these decisions.) Steve * To be honest, Expose To The Left (ETTL) is probably the appropriate term for the practice of preserving highlights by intentional underexposure with intent of attempting salvage of the shadows in post. Last edited by stevebrot; 07-04-2018 at 10:44 PM. Reason: confession of mixed terms

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07-01-2018, 11:10 AM	#2
photoptimist Pentaxian Join Date: Jul 2016 Photos: Albums Posts: 5,122	Any chance you were in spot-metering mode with something darkish in the center?

07-01-2018, 11:13 AM - 6 Likes	#3
Not a Number Moderator Join Date: Mar 2012 Location: Venice, CA Posts: 10,526	What happens in LV stays in LV.

07-01-2018, 11:33 AM	#4
biz-engineer Pentaxian Join Date: Feb 2015 Photos: Gallery Posts: 12,231 Original Poster	Originally posted by photoptimist Any chance you were in spot-metering mode with something darkish in the center? Well, I've tried spot metering, center weighted and matrix metering modes and it did not change the histogram being stuck on the right. Only thing I could think of was that most surrounding was green, so the quantity of green may have fool the metering.

07-01-2018, 11:38 AM	#5
twilhelm Loyal Site Supporter Join Date: Feb 2009 Location: Florida Photos: Gallery \| Albums Posts: 2,369	So I understand you, the LV histogram shows it heavy right, but the actual photo is heavy left? I ask because I’m wondering, if it’s a bright day, light coming into the viewfinder May skew the shot.

07-01-2018, 12:27 PM	#6
biz-engineer Pentaxian Join Date: Feb 2015 Photos: Gallery Posts: 12,231 Original Poster	Originally posted by twilhelm So I understand you, the LV histogram shows it heavy right, but the actual photo is heavy left? I ask because I’m wondering, if it’s a bright day, light coming into the viewfinder May skew the shot. Yes the lv histogram hits the right and the shot is correctly exposed or even underexposed. In lv mode the exposure is metered via the image sensor directly, I don't think light through the ovf would change anything. I've obstructed the ovf with my hand and the lv histogram stayed stuck on the right.

07-01-2018, 01:17 PM	#7
stevebrot Otis Memorial Pentaxian Join Date: Mar 2007 Location: Vancouver (USA) Photos: Gallery \| Albums Posts: 42,007	I don't have a K-1 and generally ignore the LV histogram display, but dug out the K-3 to see what you are talking about. Originally posted by biz-engineer In lv mode the exposure is metered via the image sensor directly The LV histogram is a strange beast. One might think that it is based on the actual sensor response, when near as I can tell, it actually reflects the state of the rear LCD display buffer which brightness and contrast is adjusted according to the exposure settings relative to the metered LV as well as the custom image settings for JPEG processing. It does a good job of predicting the actual JPEG capture histogram under most circumstances. I tried to reproduce your problem on the K-3, but could not unless ISO were set fairly high and/or EV were set low for a high LV scene (basically a scene requiring HDR to service both highlights and shadows). Steve

07-01-2018, 01:22 PM	#8
Mikesul Loyal Site Supporter Join Date: Sep 2009 Location: Phoenix, AZ Posts: 7,594	I just played around with live view on my K-1 and the histogram is clearly not reliable. It was not stuck on the right and moved around as if responding to the exposure but the histogram of the photo was not at all like what the live view showed.

07-01-2018, 01:25 PM	#9
twilhelm Loyal Site Supporter Join Date: Feb 2009 Location: Florida Photos: Gallery \| Albums Posts: 2,369	Since the brightness of the screen is adjusted to make it easier to view (ie brighter than the actual scene) is it possible this is what the histogram is in context with, as opposed to the actual recorded image? Just a shot in the dark.

07-01-2018, 01:28 PM	#10
Mikesul Loyal Site Supporter Join Date: Sep 2009 Location: Phoenix, AZ Posts: 7,594	Originally posted by twilhelm Since the brightness of the screen is adjusted to make it easier to view (ie brighter than the actual scene) is it possible this is what the histogram is in context with, as opposed to the actual recorded image? Just a shot in the dark. But that does not make it very useful. I did not have much time to check it so I willwork with it a little when I have some time. I do not use a tripod much so i never noticed anything before.

07-01-2018, 02:35 PM	#12
Mikesul Loyal Site Supporter Join Date: Sep 2009 Location: Phoenix, AZ Posts: 7,594	I am surprised because, although I rarely shoot with live view and have even more rarely checked the histogram before shooting, i have always assumed that the advice given to shoot with the histogram was universally applicable. I have consulted the histogram frequently after a shot where it has been very helpful. I guess I need to stop feeling guilty for not using it before a shot.

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07-01-2018, 09:30 PM	#13
biz-engineer Pentaxian Join Date: Feb 2015 Photos: Gallery Posts: 12,231 Original Poster	Originally posted by stevebrot One might think that it is based on the actual sensor response, when near as I can tell, it actually reflects the state of the rear LCD display buffer which brightness and contrast is adjusted according to the exposure settings relative to the metered LV as well as the custom image settings for JPEG processing. I changed the LV outdoor settings to see if it would affect the centering of the LV histogram, and I can say that the outdoor settings did not affect the LV histogram. However, I noticed a strange thing: in live view mode, the scene is displayed continuously with the histogram being shifted in the right, but a centered LV histogram appeared for a very short time when I half pressed the shutter button for focusing, when focusing was done, the histogram went back to the left again. Could it be that the camera adjusts aperture and "shutter speed" (electronic only shutter) to adapt to lighting conditions in order to stream images such as in video mode and that in bright light the sensor is not able to achieve short enough capture time? If it was so, the image projected in LV would be blown out. I would rather think this case of histogram looks like a software bug.

07-01-2018, 09:34 PM	#14
stevebrot Otis Memorial Pentaxian Join Date: Mar 2007 Location: Vancouver (USA) Photos: Gallery \| Albums Posts: 42,007	Originally posted by biz-engineer I changed the LV outdoor settings to see if it would affect the centering of the LV histogram, and I can say that the outdoor settings did not affect the LV histogram. However, I noticed a strange thing: in live view mode, the scene is displayed continuously with the histogram being shifted in the right, but a centered LV histogram appeared for a very short time when I half pressed the shutter button for focusing, when focusing was done, the histogram went back to the left again. Could it be that the camera adjusts aperture and "shutter speed" (electronic only shutter) to adapt to lighting conditions in order to stream images such as in video mode and that in bright light the sensor is not able to achieve short enough capture time? If it was so, the image projected in LV would be blown out. I would rather think this case of histogram looks like a software bug. Change custom mode to cross-process and see what happens. The histogram looks to be driven from the LCD display buffer. Steve

07-01-2018, 09:40 PM	#15
biz-engineer Pentaxian Join Date: Feb 2015 Photos: Gallery Posts: 12,231 Original Poster	Originally posted by stevebrot Change custom mode to cross-process and see what happens. The histogram looks to be driven from the LCD display buffer. Yes, the histogram is supposed to represent the JPEG setting, I've checked that the JPEG setting did not have exposure bias. I'll try what you say and investigate further, as it is good to know if there are some limitations when using the histogram in live view.