M-D 262 (or even M240)..Strange Thumnails

[DandA]

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Hi All,

Not an earth shattering issue but more of a curiosity type question.  On a Windows 10 PC, when I go to file explorer and open the image files in a folder to view the thumbnails of images taken with a M-D 262, I noticed two things that were very different from the thumbnails from a M9 or M10. The M9 and M10 thumbnails (shooting only RAW) at each thumbnail size are roughly the same size.  On the same computer(s), the files from the M-D 262, are approx. 30% smaller and each horizontal image thumbnail has a decent size black band across the very top of the image (although it's not cutting into any portion of the image).  On vertically taken images (and thumbnails), this band runs along the right side edge of the thumbnail (of course depending on the orientation I held the camera).  Once the thumbnail is clicked on to open in Photoshop, all is normal with image and no black band is present. 

Why should a thumbnail derived for a M-D 262 differ in size (30% smaller) and with a moderately thick black band on one edge of the thumbnail), while a thumbnail from a M10 (same size sensor) or M9 exhibt a larger thumbnail and no black band.  Aspect ratio's of the sensors from all 3 cameras should be the same.  Do others who use a PC, esp Windows 10 (or even a Mac) notice this black band (and also smaller size difference with either a M-D 262, regular 262 or even a M240 but not with a M10 or M9 thumbnail(s) derived from a DNG's?  Thanks in advance for any enlightenment.

Dave (D&A)

Edited December 26, 2018 by DandA

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[a.noctilux]

I quote the "Press Information Leica M-D", here :

Quote

Picture format/image sensor: CMOS type, active area approx. 23.9 x 35.8mm
(corresponds to usable format of analog Leica M models)
Resolution: 5976 x 3992 pixels (24MP)
Data format: DNG™ (raw data), compressed loss-free, JPEG
File size: depends on subject

In M-D, files are "compressed loss-free" and depends on subject in file size.

What we see in thumbnail is 160x120 (in Windows 10), I don't know for the "black band" though.

[pico]

1 hour ago, DandA said:

Why should a thumbnail derived for a M-D 262 differ in size (30% smaller) and with a moderately thick black band on one edge of the thumbnail), while a thumbnail from a M10 (same size sensor) or M9 exhibt a larger thumbnail and no black band. 

Blame Microsoft. The black band incurs no overhead regarding file size - it is only how the image is presented. Can you tell if the images on-disc have different sizes, and are they on the very same disc?

[DandA]

I appreciate the responses so far. Pico, when you mention and ask about the images on disc, what are you referring to by "disc" ? Did you mean hard drive?

All I am doing is looking at the thumbnails that are either on the SD card or images downloaded from the SD card onto the PC hard drive. I could understand if Microsoft (in Windows 10) displayed a quite thick black band on one side of each thumbnail displayed in all images from a M9, M-D 262, and M-10, but it's only with M-D 262 images (don't know about M240 images). The size in pixels of the thumbnails from the M-D 262 are of course much smaller than from the other two camera and display as being smaller. As for the actual full size files from each camera, yes, the full size files do vary somewhat in size as they should. 

From what I recall both the M-D 262 and M10 were shot RAW lossless compressed and so was the M9. So again I am confused why only the M-D 262 displays 30 to percent smaller thumbnails always with a thick black band on one side of each thumbnail images and not so with the thumbnails from the other two cameras INCLUDING files from a MM (M9 based) monochrom, which I just took a look at moments ago. Even if I take account the area of the black band, the entire thumbnail including the black band from M-D 262 would still be much smaller than all the other Leica M digitals I mentioned.u

Would love to get a hold of a RAW files from both a M240 and M262 to see how their thumbnails are displayed. Again thanks.

Dave

[Exodies]

The embedded thumbnails from a 240, when displayed on an iPad have a black band along the long edge. This is because the thumbnails are displayed in a fixed size tile (ratio 4:3) which has a different ratio to the thumbnails (3:2). 

Do the Windows thumbnails have a standard aspect ratio? Are you sure the M10 thumbnails aren’t cropped (a slice taken off each short side)? I’m thinking there may not be enough pixels in a M-D 262 thumbnail to sensibly crop it. 

[DandA]

Exodies,

The 1st of your two paragraphs makes a lot of sense and I will go back and check whiter Windows (esp Windows 10) has a fixed ratio for thumbnails. With that said, lets assume Windows does and it happens to be 4:3 (which would result in the dark bank due to the thumbnails being in an aspect ratio of 3:2.  Up to this point that would make sense.  Here's the rub.  The aspect ratio of thumbnails from the Leica M9 and M10 raw files should be precisely the same as the M-D 262...but when viewed on a Windows PC they aren't.  Not only do the thumbnails from the M9 and M10 don't have the black (dark) band, they are also 30% larger in size.  If Windows does have a fixed ratio, then all thumbnails from these three cameras should be the exact same size and all should have a black band.  Something doesn't add up but you're onto something Exodies!  Thank you!

Dave

 

 

[ramarren]

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I checked the thumbnail previews out of both M-P typ 240 and M-D typ 262 DNG files: they are the same size, 3:4 proportion, and both show the black band at the top. These previews are there simply for the standard LCD display in the typ 262 and 240 cameras. Their tag in the DNG EXIF data is "PreviewImage". 

The M9 DNG thumbnails, on the other hand, are the 2:3 proportion format, are in the EXIF under the tag "PreviewTIFF" and size out to be much larger. 

Now, I'm not sure about one thing: I know I never set my M-P to output anything but DNG files, and the M-D only outputs DNG files, but for the M-9 I might have had JPEG+DNG file output enabled at that time. If I had JPEG+DNG enabled on the M-P, it's quite possible that the thumbnails might be larger or sized differently depending on the JPEG settings I was using. I never archived any of the in-camera JPEG files so I cannot tell for sure how I had the camera set up. 

[DandA]

Thank you for comparing the thumbnails from your M-P 240 and M-D 262 vs. M9. If we assume the aspect ratio of 3:4 of the thumbnails from the M-P 240 and M-D 262 is specified due to their rear respective rear LCD screens and likewise an aspect ratio of 2:3 from the M9 due to the aspect ratio of its rear LCD screen (assuming all thumbnails were derived from only strictly shooting  DNG), it raises a few questions.

1. Are the aspect ratio of the three aforementioned cameras really different? Size wise yes, but their aspect ratio?

2. Why then do the thumbnails from the M10 display in both size (larger than M-P 240) and with no black band much like the M9? I would have thought the M10 thumbnails would be akin from those from the M-P 240?

Again none of this is of earth shattering proportion, but simply trying to understand why thumbnails from these various full frame sensor cameras generate quite different thumbnails from their respective DNG files and the root cause now doesn't appear to be generated by Windows itself. A bit curious.

As a side note, the considerably larger thumbnails from the M9, M10 are certainly easily to work with when doing a cursory "overview" examination of the files when doing a preliminary search. Thanks again for all the info.

Dave

[Exodies]

Could you provide pictorial evidence that the M10 thumbnails aren’t cropped when shown by windows.

[DandA]

4 hours ago, Exodies said:

Could you provide pictorial evidence that the M10 thumbnails aren’t cropped when shown by windows.

Once I get back to my computer in a couple days, I'll attempt to do just that. I don't own a M10 but did test it out on a number of occasions and that's how I came by the files (saved them on my own SD card). Although I always shoot DNG only, I'll have to see if those test images were taken with the M10 set to DNG only or DNG + Jpeg. If Jpegs were invoked, then that would throw a monkey wrench into the thumbnails generated by that camera, although I could seperate the DNG's and put them in their own folder. I'll get back to you on this regarding if the M10 thumbnails are cropped or not relative to the actual image captured.

Dave

[marchyman]

Images from my M 262 have the black band when imported into lightroom -- for however long it takes lightroom to generate it's own preview image, usually no more than 10-15 seconds on my machine.  I don't recall my Lightroom settings.  Here is a screen shot from the import screen.

 

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You can see the black band at the top.  The same band was there after import --- for a few seconds.  Now it looks like this:

It does look like the the Leica generated preview is a 3x2 image with a black band added to get to a 4x3 aspect ratio

[DandA]

marchyman, that's precisely what I observed.  Why then on same computer and program, does M10 thumbnails not exhibit the black bands and also the thumbnails are maybe 30% larger?  The M9 thumbnails are also precisely the same as the M10.

Dave

[Exodies]

Curious information from Chromasoft's web site http://chromasoft.blogspot.com/2017/01/leica-m10-raw-file-dng-analysis.html

Unusually, the DNGs all contain 3 different JPEG preview images in addition to the main raw image, one of 1440x960, one of 160x120, and finally a full sized preview of 5952x3968

The smallest one is 4:3 but the other two are the sensor's native 3:2. Hard to understand why they would make a 4:3 preview. I've had a quick look for information on M9 and M240 preview sizes but gave up before finding any.

[marchyman]

17 hours ago, DandA said:

marchyman, that's precisely what I observed.  Why then on same computer and program, does M10 thumbnails not exhibit the black bands and also the thumbnails are maybe 30% larger?  The M9 thumbnails are also precisely the same as the M10.

Simplistic answer not meant to be rude or condescending: because the different cameras use different software on different hardware platforms.  Someone on the Leica development teams may know the reason for the differences.   I'd be surprised if Sales or Marketing staff know.  They may not even be aware of the difference.   I don't think you'll ever get an explanation.  Just like I'll never get an explanation as to why the M uses compressed (lossless) DNG files but the Q doesn't compress giving me a 40+ MByte file where a 25+ MByte file would do.

And speaking of  the Q:  It has a 3:2 rear LCD.  The M 262 has a 4:3 LCD.  That is probably why the Q previews dont have the black band.

[DandA]

Marchyman, I couldn't agree more with your explanation. Someone knows the reasons for the different ways the thumbnails are generated for the aforementioned cameras. In fact the Leica X vario also has thumbnails with no black band. Thumbnails with back bands are also smaller in size, even if the black band is included in the measurement and the non black band thumbnails are more useful and easier to work with when quickly looking for a particular file...simply because of its larger size.

Someone in Leica knows the answer, I'm sure. Should I start making calls ? :).

Dave