Q2 Mono image size and readability

[pcgarner]

Advertisement (gone after registration)

If anyone knows ... I own a Q2M which, in the tech manual, purports to generate a JPG of 47 MB (under the L setting, or large): I'm instead generating images of around 20. Help!

As puzzling, my DNGs are not readable in Nik's Silver Efex Pro. I've converted a few of the images using Adobe's DNG Converter without luck. Efex states that it supports the Q2. So I'm totally flummoxed.

Any help or guidance would be greatly appreciated!  

[Advertisement]

The Leica Q3 is available for pre-order at B&H Photo Video and Adorama

[frame-it]

2 hours ago, pcgarner said:

If anyone knows ... I own a Q2M which, in the tech manual, purports to generate a JPG of 47 MB (under the L setting, or large): I'm instead generating images of around 20. Help!

As puzzling, my DNGs are not readable in Nik's Silver Efex Pro. I've converted a few of the images using Adobe's DNG Converter without luck. Efex states that it supports the Q2. So I'm totally flummoxed.

Any help or guidance would be greatly appreciated!  

silver efex can now open DNG files??

interesting i thought it opened tiff and other formats but not raw dng

[pcgarner]

You may be right as I'm failing with Efex. Since posting I've found that Exposure 7 definitely opens Leica's DNG and allows export as a TIFF (creating a 280MB file at 300 dpi). So it appears my workflow is going to be to import DNGs into Exposure 7 and then export as either a JPG or TIFF.

I'm still puzzled about why the L JPG generated by the Q2M at 28mm is not greater than 20MB. Anyone with ideas?

[kirkmc]

3 hours ago, pcgarner said:

You may be right as I'm failing with Efex. Since posting I've found that Exposure 7 definitely opens Leica's DNG and allows export as a TIFF (creating a 280MB file at 300 dpi). So it appears my workflow is going to be to import DNGs into Exposure 7 and then export as either a JPG or TIFF.

I'm still puzzled about why the L JPG generated by the Q2M at 28mm is not greater than 20MB. Anyone with ideas?

Maybe because there’s no color data. If I’m not mistaken, it should have 4096 shades of gray. It’s much less data than billions of colors.

[pcgarner]

Logical, but the Q2M tech manual indicates that a 28mm JPG shot with the Monochrom yields 47 MP. 

[kirkmc]

Of course, but each pixel contains less information. There are more possible variations for a color pixel than for a black/white pixel. Also, they probably compress more efficiently for that reason.
 

 

Edited June 24, 2023 by kirkmc

[pcgarner]

Advertisement (gone after registration)

Thanks, Kirk. Makes sense. What threw me was Leica's tech section. The Q2 has a 47MP sensor, and that's what they appear to be keying off, not the actual image size.

[Anakronox]

Megapixels - MP

Megabytes - MB

These aren’t the same thing.  Megapixels refers to the millions of pixels comprising the image.  Megabytes are the amount of storage space that the total file takes up.  This isn’t a 1:1 ratio.  
 

Edit: JPEGs are compressed and throw away image data.  Leica DNGs are uncompressed and do not lose image data.  You may never notice the difference by looking at the two side by side, but behind the scenes, they are different.  

Edited June 25, 2023 by Anakronox

[Guest]

46 minutes ago, Anakronox said:

....

Edit: JPEGs are compressed and throw away image data.  Leica DNGs are uncompressed and do not lose image data.  You may never notice the difference by looking at the two side by side, but behind the scenes, they are different.  

Actually Leica DNGs can be compressed. For example the 60MP M11 files are smaller than the 47MP Q2 files as the M11 uses lossless compression. I haven't received my Q3 yet, but I suspect they will be similarly compressed. Some cameras, e.g Sony a7iv allow you to select, lossy compressed, compressed, or uncompressed RAW files.

Your general point is correct though, the compression is lossless so there is not the loss of data that you get with JPEGs

[kirkmc]

I'm seeing DNGs between around 71 and 97 MB for the 60 Mp files. The largest file sizes are for photos with high ISO. The 71 MB file is ISO 100, and the 97 MB file ISO 1600. With the Q2M, they are 85-89 MB.

There's no setting for compressed DNGs on the Q3, and I'd be surprised if they were using compression on DNG files, because some photo editing apps might not be able to handle them. I saw one article suggesting that the M11 files are compressed, but I didn't find anything convincing. I don't think any camera manufacturer would use compressed DNG files without it being optional. I know that for Fujifilm files, compressed DNG isn't widely supported.

[Guest]

24 minutes ago, kirkmc said:

I'm seeing DNGs between around 71 and 97 MB for the 60 Mp files. The largest file sizes are for photos with high ISO. The 71 MB file is ISO 100, and the 97 MB file ISO 1600. With the Q2M, they are 85-89 MB.

There's no setting for compressed DNGs on the Q3, and I'd be surprised if they were using compression on DNG files, because some photo editing apps might not be able to handle them. I saw one article suggesting that the M11 files are compressed, but I didn't find anything convincing. I don't think any camera manufacturer would use compressed DNG files without it being optional. I know that for Fujifilm files, compressed DNG isn't widely supported.

Hi,

I compared my M11 DNGs with my Q2 DNGs and they are much smaller (even allowing for the increased resolution in the M11)

If you subsequently use DNG conversion in Lightroom, and select lossless compression, the Q2 files become much smaller, but the M11 ones remain more or less the same. The compression algorithm is part of the DNG spec, so if an app supports DNG it should support compression. You are right about Fuji RAWs, but that is a proprietary standard. 

[pcgarner]

Thanks, all. Exactly the feedback I was seeking.  (As an aside, I took a series of shots today with the Q2M (all daytime, low ISO) and all came in slightly above 90MB.)

Edited June 25, 2023 by pcgarner

[beewee]

3 hours ago, kirkmc said:

I'm seeing DNGs between around 71 and 97 MB for the 60 Mp files. The largest file sizes are for photos with high ISO. The 71 MB file is ISO 100, and the 97 MB file ISO 1600. With the Q2M, they are 85-89 MB.

There's no setting for compressed DNGs on the Q3, and I'd be surprised if they were using compression on DNG files, because some photo editing apps might not be able to handle them. I saw one article suggesting that the M11 files are compressed, but I didn't find anything convincing. I don't think any camera manufacturer would use compressed DNG files without it being optional. I know that for Fujifilm files, compressed DNG isn't widely supported.

The fact that the file sizes change between shots means there is most definitely file compression being applied to the DNGs.

Data compression works on the principle of reducing the number of bytes required to store redundant information that can be replicated by the decompression algorithm. If there’s lots of redundant data such as an image that is very uniform (take a black frame with the lens cap on at ISO 100 exposed for 1/125s) then you’ll get smaller files. If there’s lots of data that is not redundant such as an image that is very non-uniform (take a black frame with lens cap on at ISO 100,000 exposed for 30s so it has lots of random noise in the image) then you’ll get larger files.

Also, just because the camera doesn’t have settings for enabling/disabling compression, it doesn’t mean compression isn’t taking place. DNG files is a well defined format and settings/information for how to decompress the image data can easily be embedded into the metadata within the DNG file to tell the raw processing software how to decode the compressed data, which algorithm/method to use, etc.

There are also different forms of compression/decompression algorithms, some are lossless which means you can regenerate the original data without any loss of information when decompressing, and lossy algorithms which means you can get something very close to the original but not all the information from the original will be retained upon decompression. I expect Leica would choose a lossless compression algorithm so as not to lose any information and in this way, if that is the case, no one would complain that they are compressing the image data because there’s no downside to this approach except a bit more processing on the post processing software’s part to decompress the image when importing/exporting and even then, the algorithms used can be made incredibly computational efficient as to have pretty much no impact on overall processing speed relative to everything else that your post processing software has to do to render and export the edited image.