JPG resolution loss

[sergiolov]

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It's a known fact that there is a resolution loss in jpg fine compared to the conversion from dng. I remember amongst others a post from Jono asking for a less compressed jpg fine.

But how big is this loss? Well, it is big!

 

First image is 100% crop from ipg fine, second is a straight conversion from dng in CS3, with only convert to grayscale applied.

 

I am sure that Leica can improve the internal ipg engine.

 

Sergio

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[Guest guy_mancuso]

In a meeting last week with leica , i did bring up Jono's request for less compression on the jpg fine setting and they made note of it for future firmware. All i can do is ask,let's see what comes. But i do agree that the jpegs are getting to compressed on this setting. i know some may argue they will get less images on a card . Frankly IMHO who cares just buy more cards there cheap as can be and rather have a better image than worry about card space.

 

BTW pretty amazing sample of this that you done.

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[rob_x2004]

Do you mean this is a crop out of the very much larger frame and we see the crop at full size.....or do you mean this is the full frame ie the entire picture and you have resized it so we see teh whole frame?

 

If this is a crop out of the full frame what are teh pixel dimensions of the whole frame?

[martinb]

The M8 JPEG's sucks. I hope they'll do something about them, because I think JPEG is useful for some work.

[jonoslack]

HI There

I don't think the jpgs suck - I think that they're pretty good EXCEPT that they're too compressed. I can't see that it would be too much of an issue to change the compression ratio for them - Olympus have a 1:2.7 compression on the E1, which produces 5 or 6mb files (so the Leica files would be around 10mb).

Thanks for bringing this up Sergio - and thanks for mentioning it in Solms Guy.

 

Let's just hope something is done about it, shooting jpg often a good thing - if they're good enough!

[carstenw]

I also asked the Leica mechanic who visited Berlin to pass this suggestion on to Stefan Daniel, the product manager. If they hear it from enough people, they will surely do it.

[marknorton]

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Interesting example, I too would like Leica to do more work on the JPEG engine.

[rob_x2004]

So is the image above a crop or full frame?

[martinb]

HI There

I don't think the jpgs suck - I think that they're pretty good EXCEPT that they're too compressed. I can't see that it would be too much of an issue to change the compression ratio for them - Olympus have a 1:2.7 compression on the E1, which produces 5 or 6mb files (so the Leica files would be around 10mb).

Thanks for bringing this up Sergio - and thanks for mentioning it in Solms Guy.

 

Let's just hope something is done about it, shooting jpg often a good thing - if they're good enough!

 

Have a look at this http://www.l-camera-forum.com/leica-forum/digital-forum/13602-m8-high-contrast-sharpening-issues-jpeg.html and you'll understand why I think the JPEG's suck. They're not only soft, but even worse, they're full of artefacts. To less degree if you turn off the sharpening though.

The M8 JPEG performance is the far worst I've seen so far and I'll hope they will do something about it.

[Bob Ross]

Hi Sergio,

Nice set of comparison images. They do point out the differences in the tone curve renderings. The DNG crop has more mid tone contrast and subdued highlights, which increases the midtone detail rendering. In fooling around with JPEGs, I can pretty well match them to the DNG conversions, but it would be nice if I didn't have to fool around so much. I think the JPEG issues are compression (with artifacts possible) and the tone curve (smears in midtone detail).

Bob

[sergiolov]

So is the image above a crop or full frame?

 

It is a crop from a 100% enlargement. This is the full image.

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[sergiolov]

HI There

I don't think the jpgs suck - I think that they're pretty good EXCEPT that they're too compressed. I can't see that it would be too much of an issue to change the compression ratio for them - Olympus have a 1:2.7 compression on the E1, which produces 5 or 6mb files (so the Leica files would be around 10mb).

Thanks for bringing this up Sergio - and thanks for mentioning it in Solms Guy.

 

Let's just hope something is done about it, shooting jpg often a good thing - if they're good enough!

 

Hi Jono,

It seems to me that it is not only a question of compression ratio, but also of internal jpeg engine quality. I get this impression because in this case, the from camera jpeg is 2,9 MB and the jpeg converted from dng (quality level 11) is 2,6 MB.

Obviously, conversion algorythms in CS3 backed by a powerful processor have a strong advantage...

They should probably refine the internal jpg converter and offer a third jpeg option in firmware.

 

Best regards.

Sergio

[rvaubel]

Hi Jono,

It seems to me that it is not only a question of compression ratio, but also of internal jpeg engine quality. I get this impression because in this case, the from camera jpeg is 2,9 MB and the jpeg converted from dng (quality level 11) is 2,6 MB.

Obviously, conversion algorythms in CS3 backed by a powerful processor have a strong advantage...

They should probably refine the internal jpg converter and offer a third jpeg option in firmware.

 

Best regards.

Sergio

 

Your right, the CS3 JPEG conversion barely affects resolution at all. I never take in camera JPEGs but often convert DNG files to medium or low quality JPEGS in CS3 for emailing to friends and relatives. Even a high compression doesn't have that much effect on resolution. The sample of the internal jpg converter is pretty scarey.

 

Rex

[sergiolov]

Your right, the CS3 JPEG conversion barely affects resolution at all. I never take in camera JPEGs but often convert DNG files to medium or low quality JPEGS in CS3 for emailing to friends and relatives. Even a high compression doesn't have that much effect on resolution. The sample of the internal jpg converter is pretty scarey.

 

Rex

 

My experience, which confirms what Jono and BJF noted shortly after the m8 was released, is that the internal jpg engine is very good with color fidelity and (incredibly) with dynamic range preservation. DR is 1/2 stop more than what is obtained with the best external converters. But for resolution and artifacts there is a lot of work to do.

 

Sergio

[jonoslack]

Have a look at this http://www.l-camera-forum.com/leica-forum/digital-forum/13602-m8-high-contrast-sharpening-issues-jpeg.html and you'll understand why I think the JPEG's suck. They're not only soft, but even worse, they're full of artefacts. To less degree if you turn off the sharpening though.

The M8 JPEG performance is the far worst I've seen so far and I'll hope they will do something about it.

 

HI Martin

I quite understand what you're saying, but turning off in camera sharpening is simple enough (and the right thing). If they reduced the compression they should also remove the artifacts and increase the resolution.

 

On the other hand, as Sergio points out, the colour is fine, and the DR is even better than the jpgs - I've also found that the mid tone smearing that Bob talks about is removed by dropping the sharpening, and, more importantly, dropping the saturation to medium low.

 

Of course, I could be wrong, but I return to my point - they aren't okay, but they're soooo nearly really fine!

[rob_x2004]

It is a crop from a 100% enlargement. This is the full image.

 

 

Thanks for putting it in perspective. In context then, obviously there is nothing wrong with Leicas JPG compression. Its a JPG if you want the convenience of compression then there is a trade off. Youi have other file formats when you need absolute calrity. Thanks for the frightener.

[Guest stnami]

it's a jpeg!!! has it's uses in the big picture................ the engine processor is generic tailored for a general population and result. If you want your own do as you already......... shoot raw and process.

What do you guys want leica to do everything for you.. wipe your backsides as well. Get real it's a camera created but, not with you as an individual in mind. Remember you put the bucks down on a untested camera and you knew that before you bought....... hence the quirks.............

[jonoslack]

it's a jpeg!!! has it's uses in the big picture................ the engine processor is generic tailored for a general population and result. If you want your own do as you already......... shoot raw and process.

What do you guys want leica to do everything for you.. wipe your backsides as well. Get real it's a camera created but, not with you as an individual in mind. Remember you put the bucks down on a untested camera and you knew that before you bought....... hence the quirks.............

Finished?

What's wrong with asking for less compression? As far as i can see that's all that's needed to make them useable in lots of cases.

It's not a quirk, they have excellent colour and dynamic range.

I doubt if there is anyone here who doesn't also shoot RAW and process.

Why stick a rant into a civilised discussion?

[rob_x2004]

Jon what I was driving at is that people come here to get a feel for what is going on with the m8 and it all reads pretty scary, when often that isnt justified. Putting a crop up without seeing where it comes from, or in some cases without exif to examine, doesnt really help.

 

Aside that, jpg has a useful existence. If you need resolution, which isnt always the b all and end all, then you have other file formats, and it is only one extra tap or click in your workflow to convert to jpg from them.

 

And lets approximately put it in perspective

 

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[adan]

Two things happen in jpegs that are not user-adjustable, and have a big impact on resolution:

 

1) Anti-alias filtering. Remember the control on the DMR to turn the AA moire filtering on or off? There is no such option on the M8. Jpegs are filtered, DNGs are not filtered. Result - a fuzzier image (see the nearby thread on "plasticky" DSLR images) in jpegs.

 

2) Noise reduction. It is easy to see, in comparing jpegs and DNGs from the M8, that the in-camera processing includes significant noise-reduction routines, which smooth away detail as they smooth away noise speckles. The M8 does avoid the 'brush-stroke" noise reduction texturing of the PanaLeicas (viz. Digilux 2) - but detail still gets lost.

 

(OTOH, the M8 does an interesting job of evening out shadow and highlight noise in jpegs at 1250/2500, which gives them a more film-like look. If Leica could restore user control of AA filtering in jpegs, I kinda like the NR technique they've chosen)

 

3) although it is sort-of user-controllable, the jpeg sharpening is also flawed, as we've noted here before. It sharpens edges too much, and textures not enough, resulting in a video look, and edge artifacts on hard highlight/shadow edges.

 

I have noticed occasional faint jpeg "squares" in fine jpegs, and that surprised me. Not anything that would show in most prints - but too much for a "Fine" jpeg. The Digilux 2 compressed 5 Mpixels to 2.6 Mbyte files - the M8 by extension should have at least 5.5 Mbyte fine jpegs, or they are too compressed.