Histogram and jpg contrast

[tgray]

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I’m sure this is common knowledge, but the jpg contrast settings on the M10M affect the histogram clipping indicators.  The settings also affect the DNG thumbnail even if you are shooting DNG only. 

[Wonzo]

Many thanks for this information! It would have been my last guess, that JPG settings also affect DNGs ...

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[fotografr]

I doubt if this is common knowledge because many people, like myself, never shoot anything but DNG. The jpeg contrast settings have no effect on the DNG, so I'm sure many of us never change the setting from "normal."

To be clear, this setting affects only the thumbnail.

Edited March 12, 2020 by fotografr

[tgray]

Yes it only affects the thumbnail. I only shoot DNG as well but was playing with the settings on the new camera. I shot a few frames in JPG, fiddled with the contrast, then went back to DNG only without resetting the contrast.

I now actually have it set to low contrast because it gives me a better idea of what was actually captured (I think).  

[SrMi]

The histogram is based on the captured/live-generated JPG. The camera's JPG settings affect the live-view (EVF or LCD), the histogram, and the stored thumbnail. AFAIK, the same behavior is seen on most cameras, monochrome and color. The JPG settings do not affect the raw files.

[davidmknoble]

7 hours ago, SrMi said:

The histogram is based on the captured/live-generated JPG. The camera's JPG settings affect the live-view (EVF or LCD), the histogram, and the stored thumbnail. AFAIK, the same behavior is seen on most cameras, monochrome and color. The JPG settings do not affect the raw files.

That's a good explanation.  In general, I would think, if the JPG has a histogram that is "good" or not over- under-exposed terribly, the RAW image should have the detail to push and pull in either direction.  However, if the JPG settings are strong in any direction - max / min contrast / brightness, that might not hold as true.

[zeitz]

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"Raw Image"?  There is no such thing.  A raw file consists of the values read from the pixels in a table format.  To "see" a raw file the image must be processed using some profile in the camera or on the computer into an image file format that a monitor can display.

[davidmknoble]

1 hour ago, zeitz said:

"Raw Image"?  There is no such thing.  A raw file consists of the values read from the pixels in a table format.  To "see" a raw file the image must be processed using some profile in the camera or on the computer into an image file format that a monitor can display.

I'm sorry I used a term not technically perfect.  You are correct, we have RAW files that are used to display images upon processing through a RAW converter. I understand what the RAW file holds.  However, if the pixels from the sensor have been overexposed (filled to the limit) or underexposed (not enough light to exceed the read noise), then you would like to know that while you still have an opportunity to adjust your exposure and take another image.  The OP noted that the histogram available at the time of taking the picture is measured from the JPG, processed from the RAW file.  My point is, that if the histogram on the JPG is reasonable, then you have the data in the RAW file at the extremes and can process it accordingly.  I just tried to say it in a more simple matter.  My apologies.

[zeitz]

No apology needed.  The raw file specification, with all the metadata that is stored in it, gives the camera's software a lot of latitude for what is presented on the screen.  (The .dng raw format specification also allows the adjustments that are made in a raw converter to be stored in the raw file.  Other raw formats relay on a sidecar file to hold the additional adjustments to be stored.)  The histogram is an excellent tool to judge the exposure.  "Expose to the right" is the common recommendation.  You certainly don't want to blow out the highlights.  But some intense reflections, like in an auto's chrome, have to be tolerated to avoid blocking the shadows.

[Jeff S]

10 hours ago, SrMi said:

The histogram is based on the captured/live-generated JPG. The camera's JPG settings affect the live-view (EVF or LCD), the histogram, and the stored thumbnail. AFAIK, the same behavior is seen on most cameras, monochrome and color. The JPG settings do not affect the raw files.

The original Monochrom had a DNG based histogram, which appeared after a short delay following the initially generated JPEG version, and even was divided into ‘zones’ (pages 95, 140 in the manual). I don’t know if the M246 and/or M10M shares this feature, having received no definitive response from insiders here, and not having tested either camera.

Jeff

[davidmknoble]

2 hours ago, Jeff S said:

The original Monochrom had a DNG based histogram, which appeared after a short delay following the initially generated JPEG version, and even was divided into ‘zones’ (pages 95, 140 in the manual). I don’t know if the M246 and/or M10M shares this feature, having received no definitive response from insiders here, and not having tested either camera.

Jeff

Now that you say that, I remember.  The first histogram was in a rectangle, the second one had the vertical lines.  My recollection is that the second one simply shows the brightness measurements from the sensor data as the RAW file was written.

I just took an image of my computer screen with this post using the M10M and Summilux 35.  What I noticed was that the histogram appears almost instantly, which given the increase in technology from the M9M, would make sense regardless of what data is used.  There is no change in histogram nor a change in display (i.e., no vertical lines adde).  As you zoom into the image, the histogram appears to adjust based on the portion of the image in the view.  I would assume that it is related to the JPEG, but I will certainly email support through the leica owner's site and ask for clarification.  

[Jeff S]

I find the DNG-based histogram on the MM1 particularly useful as a tool to help avoid blown highlights, which of course is more problematic with Bayerless sensors having no color channel highlight recovery. Shame if the latter two iterations don’t incorporate this feature. If not, I wonder if there is a technical hurdle. e.g., CMOS vs CCD, or something else. Someone here did write, however, that the M246 received a FW update to provide a DNG histogram, but I don’t recall any confirmation.

Jeff

[davidmknoble]

I've sent an email requesting clarification given the M9M dual role histogram.  Will report if I get a response!

[davidmknoble]

Ok, I think we all knew this, but Leica Camera AG confirmed that the histogram in the M10 Monochrom is from the JPEG, unlike the secondary histogram from the M9M.  They also indicated this was like most of the Leica Cameras.  I did not ask which cameras might not use the histogram.

[Jeff S]

3 hours ago, davidmknoble said:

Ok, I think we all knew this, but Leica Camera AG confirmed that the histogram in the M10 Monochrom is from the JPEG, unlike the secondary histogram from the M9M.  They also indicated this was like most of the Leica Cameras.  I did not ask which cameras might not use the histogram.

The only one I know with a DNG histogram, as noted above, is the original Monochrom.  Don't know about the M246; conflicting reports, and I've never used.

Jeff

[a.noctilux]

Jeff, I can confirm that my M (typ 246) shows only histogram ( from jpeg ? ) without the "zones" of my original Monochrom.

I've asked but never have positiv answer for DNG or jpeg histogram on M246.

This bothered me at first but I learn with the M246 not to rely on those histogram's fantasies, but on the flashing hi/low instead, if need be.

Try to obtain right exposure from the first frame/file is what I do most of time, and in doubt, I "manually bracket" when possible.

[louys]

I have just exchanged the M240 for the M246, and in setting up the 246 I’m puzzled that I cannot see the histogram in live view. I’m sure this was possible the 240. Am I missing something in set up or did Leica drop this in the 246?

[a.noctilux]

Hello Louys,

as with the M240, in LV push the info button twice or once if the horizon aid is off (then the shutter release first stage to preview histogram at

right bottom corner).

Edited July 11, 2020 by a.noctilux

[louys]

Thanks very much. I stumbled on it myself this afternoon when I was taking the camera for a walk. I find it very helpful. And I’m loving the Monochrom😀😀

On 7/11/2020 at 9:52 PM, a.noctilux said:

Hello Louys,

as with the M240, in LV push the info button twice or once if the horizon aid is off (then the shutter release first stage to preview histogram at

right bottom corner).

 

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[jaapv]

The only camera that uses a DNG-based histogram is the Monochrom1. On all other cameras it is based on the generated JPG. On older camera it was easy to see, the histogram and clipping warning "jumped" after a fraction of a second as the JPG got generated. The newer cameras are so fast that it is hardly visible, or not at all. The Monochrome1 was also the only camera that has a "Zone System" marking on the histogram.

Mostly the clipping warning and histogram are somewhat pessimistic, giving ½ to 1 stop leeway.