Leica Q (Type 116) poor quality embedded JPEG in DNG files

[fourtwo]

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Hi,

 

I shoot only RAW (DNG) with my Q, which I acquire a few weeks ago.

 

I am using Photo Mechanic to sort my pictures before using Lightroom to process them. The reason is that PM is much faster for "ingesting" and previewing the pictures. Fast preview is made possible because  PM uses the embedded JPEG preview from the DNG file. But when sorting the Q pictures, I had the bad surprise to discover that the quality of the JPEG previews was terrible : when zooming at 100% you definitively lose all the details that you could see in Lightroom. It is really a pain in the butt for sorting pictures, especially when you want to make sure that they are not out of focus or slightly blurry (I have trouble with pictures shot from 1/60 and under that speed with the Q).

 

So I wrote to Camera Bits (PM editor) technical support, and here is their answer :

 

The embedded JPEG in the Leica Q DNG image is very small, only 720×480 (compared to the 6000 × 4000 RAW file) so you definitely won’t get the same quality viewing that embedded JPEG.

The one option is to use Adobe’s DNG converter to create a full-size JPEG preview which will give you the same quality as the DNG image.

You can use the “Convert RAW TO DNG” option in the top Tools menu to create the full-size JPEG preview as long as you currently have a DNG Converter currently installed on your computer.

Also, you will want to uncheck the “Output to Source Folder” option (if you use this tool) in order to avoid getting duplicates of all of your images. This will let you create a new folder of the files with the full-size previews and you can throw away the original folder (or keep it as a back up).

 

I tried this tip : it does work. Ok, but that means I need to add an extra step to my workflow by converting all my DNG into... DNG so that they can include a full size embedded JPEG. How silly is that ? Of course, I can turn on an option in PM to preview direclty the DNG file instead of the JPEG, but then I can say goodbye to the speedy processing.

Is there anybody else concerned by the same problem ?

Thanks

Edited March 23, 2017 by fourtwo

[matlep]

Why not shoot both Jpg and raw? 

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[Leica Guy]

Why not shoot both Jpg and raw?

+1 Exactly.

[matlep]

In Photomechanic you can use the Jpg as a proxy for the RAW file and thereby omitting the unnecessary steps described above. Quote from the CameraBits website:

 

"Certain digital cameras are able to shoot both RAW and JPEG images at the same time. This means that there are two identical images saved to the card, one saved as a JPEG and one saved as a RAW file. Both will have the same base file name. Photo Mechanic is able to display these files in two ways:

1. Both files are displayed as a single ‘combined’ thumbnail. (Use this option)
2. Both files are displayed as two separate thumbnail

 

Using the JPEG as a proxy file means that Photo Mechanic does not have to parse the RAW file itself, which is outside the scope of the software. It uses the JPEG data for all the above transformations and exports. Using a JPEG Proxy is like using a full resolution version of the RAW file, without having to actually process it."

[beez]

That's interesting, because I shoot only DNGs with my Q, and I've used Photo Mechanic since late 2003 in beta - best picture sorting/renaming/transmitting app there is, imho. Anyway, I shoot DNG only (not DNG+jpeg) and when I double click on a picture in lightbox mode, I get a full sized 6000x4000 jpeg in the preview window.

 

With my M8 and M9s, the embedded jpeg was the very small 720x480, and I ran them through DNG converter to get full sized jpegs embedded. But when I got the Q, that all changed, and it was an unnecessary step, that I was glad to eliminate from my workflow, especially in deadline. I have the PM preferences set to "RAW: use embedded jpeg for faster view." In the camera menus, on the 2nd page of menus I have the "jpeg resolution" setting at 24/15/8M, although I didn't think that had any bearing on the size of the embedded jpegs in the DNGs. I thought it was only for what size you wanted when you shot jpegs. Check that menu setting and see what it's set to. I don't see any other menu items that might be germane to the size of the embedded jpegs in DNGs

 

My Nikons are the same - I get full-sized jpegs embedded in the NEF files.

Edited March 24, 2017 by beez

[odds]

...when I double click on a picture in lightbox mode, I get a full sized 6000x4000 jpeg in the preview window.

 

Full size 97.6% confirmed. Photo Mechanic reports my DNG-images straight from Leica Q (Firmware version 2.0) to be 6120x4016 pixels. After extracting embedded previews, Photo Mechanic reports size of resulting JPG-images to be 6000x4000 pixels.

 

I did try DNG-images straight from Leica Q with digital crop to 50mm applied, but PM still extracts 6000x4000 JPGs from the DNGs.

 

I did try to shoot DNG+JPG with 50mm crop applied. PM reports JPGs straight from Leica Q to be 3360x2240 pixels, but PM still extracts 6000x4000 JPGs from the DNGs.

 

We may however, misunderstand some information from the original poster. If the DNGs are visited by image processing software that replaces the embedded preview to make the preview show the processed result, the new preview may be smaller than the original one. But then the DNG file is not straight from the Leica Q. I hope the original poster can clarify.

 

--

Odd S.

[odds]

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... So I wrote to Camera Bits (PM editor) technical support, and here is their answer :

 

The embedded JPEG in the Leica Q DNG image is very small, only 720×480 (compared to the 6000 × 4000 RAW file) so you definitely won’t get the same quality viewing that embedded JPEG.

 

A 720x480 JPG thumbnail image is embedded in DNGs from my Leica Q, there is also a 6000x4000 JPG preview image embedded in the same DNGs.

 

--

Odd S.

[fourtwo]

Hi everyone,

 

Thanks for your answers (I was outstation for a while so I just saw them).

 

I agree with matlep and Infiniumguy, that's what I currently do : shooting RAW+JPG, it offers a very fast way to display my pictures in full resolution in PM. The only problem is that it extends the ingesting time.

 

Quite interesting what beez and odds say. So you guys have access to a full size preview ? There would be two different preview sizes in DNG ?

To answer odds, I am talking about the JPEG preview embedded from the original DNG file, the one that PM uses to display its preview. What is sure is that zooming at 100% in these previews will show that the difinition was torn down somehow in my case, which give credits to what Camera Bits says. Of course when I am using LR to preview an image from the original DNG (so a JPEG created by LR itself, not an embedded one) the problem doesn't happen, no loss of details.

 

I don't have my equipment with me right now, but I will have a look at the files size.

[fourtwo]

Hi again,

 

So I checked and yes you are right : the embedded JPEG is indeed 6000 x 4000 pixels. 

 

So as suggested odds, it probably comes from the difference between PM reading the embedded JPEG, and LR creating its own JPEG version from the DNG.

 

I give you an example of the issue : you can see it on this Dropbox link

It's a picture with a focus zone around 2.0m from the camera. I zoomed 200% on each case.

The first picture is from LR giving a preview of the DNG.

The 2nd picture is from PM giving a preview from the embedded JPEG from the DNG.

The 3d picture is from PM giving his own preview from the DNG file (when you click on "Q" on your keyboard). The result is quite terrible.

In the first case you can almost read all the writing on the film boxes, in the second case (PM preview) it looks like a lower resolution. 

 

I know, I seem to be a little too fussy ("you talk about a detail on a 200% zoom ?!") but on some pictures, for instance where you face a crowd and shooting from a quite far distance, then in one case you can almost see people's face, in the other case everything is blurry -> then I think "snap, there's a problem with the focus, I can throw away this picture". 

[odds]

...

The 3d picture is from PM giving his own preview from the DNG file (when you click on "Q" on your keyboard).

 

I do not think Photo Mechanic has a raw converter and rendering of its own. My understanding is that on a Mac the Q key "raw/jpg toggle" selects one out of two renderings, none of them created by Photo Mechanic.

 

On a Mac, the Q key toggles between the embedded JPG and an image that the Mac operating system creates/renders from doing a raw conversion of the raw file. If Mac creates a lousy image, there may not be much to do about that in Photo Mechanic. Check the Photo Mechanic preferences for possible parameters top pass to the Mac OS (I do not have a Mac and can not check for you).  Maybe some knowledgable Mac user can chime in and explain how you tweak the raw conversion in the Mac operating system, if at all possible.

 

If the Q key has any effect at all on a Windows PC, my guess would be that it toggles between the JPG embedded in the raw file and an accompanying JPG file on disk, like you get when shooting RAW+JPG. I am however; not able to provoke such toggling  in Photo Mechanic on my Windows PC. The Q key apparently has no effect whatsoever. I hard edited a JPG in a RAW+JPG pair and should easily be able to see the difference if the Photo Mechanic preview switched between the embedded JPG and the JPG-file on disk.

 

You may want to consult the Photo Mechanic online manual http://wiki.camerabits.com/en/index.php?title=User_Manual_Flat_View#RAW_Rendering There is also a little information here: http://wiki.camerabits.com/en/index.php/Preferences about one third down the page, but I will quote what I think is relevant here: "RAW Rendering is part of Mac OS X. Photo Mechanic cannot render images on Windows".

 

--

Odd S.

[odds]

...There would be two different preview sizes in DNG ?

 

Sure. There can be zero, one, two , three and more previews in addition to the raw pixel data. Embedded JPG previews may be compressed for space saving rather than image quality, but I have not tried to evaluate the compression ratio used by my Leica Q. So far I have no need for it. Judging by metadata in a DNG file from my Lieca Q, it looks like there are 3 JPG-images embedded: 720x480, 1620x1080 and 6000x4000.

[matlep]

Sure. There can be zero, one, two , three and more previews in addition to the raw pixel data. Embedded JPG previews may be compressed for space saving rather than image quality, but I have not tried to evaluate the compression ratio used by my Leica Q. So far I have no need for it. Judging by metadata in a DNG file from my Lieca Q, it looks like there are 3 JPG-images embedded: 720x480, 1620x1080 and 6000x4000.

 

That might be an explanation for the large size of the Q raw file?

[odds]

That might be an explanation for the large size of the Q raw file?

 

I do not know, but the metadata says "uncompressed" for the raw data, and I would guess that may be more significant than an additional JPEG block.

--

Odd S.

[fourtwo]

I do not think Photo Mechanic has a raw converter and rendering of its own. My understanding is that on a Mac the Q key "raw/jpg toggle" selects one out of two renderings, none of them created by Photo Mechanic.

 

On a Mac, the Q key toggles between the embedded JPG and an image that the Mac operating system creates/renders from doing a raw conversion of the raw file. If Mac creates a lousy image, there may not be much to do about that in Photo Mechanic. Check the Photo Mechanic preferences for possible parameters top pass to the Mac OS (I do not have a Mac and can not check for you).  Maybe some knowledgable Mac user can chime in and explain how you tweak the raw conversion in the Mac operating system, if at all possible.

 

MacOS can indeed natively preview DNG files from the Finder (=Explorer on WIndows), showing no vignetting or distortion (as you can see DNG files in other softwares than LightRoom that don't apply embedded corrections), my guess is that we preview the embedded JPEG. 

 

I do not know, but the metadata says "uncompressed" for the raw data, and I would guess that may be more significant than an additional JPEG block.

 

I read somewhere that the DNG size of the new M10 was more around 23 MB or so.

 

 

 

In the first case you can almost read all the writing on the film boxes, in the second case (PM preview) it looks like a lower resolution. 

 

So the difference would only be on one side : LR giving its own interpretation of the DNG with its own algorithm, on the other side : PM showing us the embedded JPEG preview (same one that MacOS is showing in the finder). And the JPEG is "less sharp" than LR preview.

[etk]

You can force lightroom to compress the dng and it reduces the file size to around 20-30MB... however this comes at a cost as the system then runs noticeably more slowly when switching between images. I've decided not to bother and just get more external storage.

[beez]

I should have mentioned that use Macs. But from what I can tell, the embedded jpeg is in the DNG at full size. For me, how ever the embedded jpeg is made, it's a seamless process - I shoot the DNGs (only) and I don't use the "ingest" command in PM, I just download the DNGs directly from the card inserted into the card slot on my MacBook Air into a folder on the Mac desktop. I drag that folder onto the PM icon in my dock, and PM renders a lightbox view of whatever is in the folder. When I double-click a frame, the preview comes up in PM as a 6000x4000 jpeg. It has the same detail and fidelity as a jpeg made from the the DNG in Photoshop (I don't use Lightroom). On my Thunderbolt 27" display, the PM preview usually comes up at around 28%. When I blow up the picture in the PM preview, I can easily check focus and detail, same as I can do if the jpeg was opened in Photoshop.

 

I don't know if the DNGs can embed more than one preview, but the DNG files themselves are 45MB becasue there's no compression on the RAW files. Many camera makers have a lossless compression they use. I have that set on my Nikons, and the 24 Megapixel NEF files are usually about 24 Mpixels. When opened in Photoshop, they're usually 48-52MB.

[odds]

 

 

...in the second case (PM preview) it looks like a lower resolution

 

 

...And the JPEG is "less sharp" than LR preview.

 

I am not sure about those two conclusions. When I look closer at those hard to read text details in you image, I wonder if the JPEG compression plays an important role (causes loss of fine details and sharpness, and I think I also see a few JPEG artefacts in thos "high frequency" areas). I tried to toggle preview sharpening on/off in Photo Mechanic, but turning preview sharpening on does not improve things in my end.

 

Like beez, I have not yet had to wrestle with the issue you describe. I do not use Lightroom much and can't really comment on it.