DNG vs Jpeg sharpness

[usccharles]

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see the attached images. one is the original image resized and the other is a 100% crops of the focused area. sharpness was turned Off for the in-camera Jpeg, DNG file was converted with Photoshop with sharpening turned Off as well. everything else is default settings.

 

why is the Jpeg image so much more blurry than the DNG file? doesn't Jpeg processing just mainly involve figuring out the whitebalance, highlights, and shadows? i don't get how in-camera processing can make the raw image more blurry than it already was to begin with.

 

sorry if this is a stupid question. i'm not all that tech savy..

 

thank you!

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[Shootist]

JPG compression. The biggest JPG file you get from in camera processing 2.5-3MBs compared to the 10.1 RAW/DNG file.

Clearly Leica never thought anyone would use JPG's as a real output for the M8.

 

Let me add it it really doesn't matter to me. If I use JPG at all it is for quick sharing with other in my office and for that the quality doesn't matter that much.

[sandymc]

In short summary form: JPEG processing involves compression via DCTs (Discrete Cosine Transforms) - that compression is why the file size is smaller. However, DCTs compress by throwing away high frequency information -> high frequency information equals edges equals you end up with blurry edges, aka decreased sharpness.

 

Sandy

[Jamie Roberts]

Regardless of JPEG compression, there also seems to be a sharpening difference, no?

 

When you set ACR in PS to "no sharpening" does it necessarily mean there is none? Or does it means "no additional sharpening"?

 

Anyone actually know?

 

IIRC, in C1 it's impossible to get rid off *all* sharpening. I thought you needed to run something like DCRAW to get truly unsharpened output.

 

Why don't you turn sharpening ON in the camera--which has its own RAW converter--and then compare? That would tell you soon enough what's going on

[ChrisC]

Charles - Far from a stupid question, and the issue of Jpeg quality has been visited several times on the forum. I shoot RAW + Jpeg and use the Jpegs for quick editing and dumping of unwanted files, and for 'playing' with an image to get a feel of where it wants to go with more serious processing. For proper image finishing I think we will all choose optimum quality over poorer in-camera Jpegs; so does it really matter that the Jpegs are worse than our own RAW process?

 

In some ways, our conventional understanding of RAW as the 'pure' file has been simplistic and a little naive. We don't get to see the RAW file, we get to see what the RAW Processor gives us, and I think we need to be a little sceptical about how unadulterated RAW processed files are. It seems, from discussions elsewhere, that the Nikon RAW processors for the new D3 are adding noise suppression 'under the hood', and the C1 files that many people like carry hidden sharpening when some workers believe that sharpening is turned off. Nothing wrong with either perhaps; but it does make comparing results form different processing softwares problematic.

 

..... DCTs compress by throwing away high frequency information -> high frequency information equals edges equals you end up with blurry edges....

 

Sandy - Thank you for that concise explanation; nicely put.

 

.............. Chris

[scott kirkpatrick]

When you set ACR in PS to "no sharpening" does it necessarily mean there is none? Or does it means "no additional sharpening"?

 

Anyone actually know?

 

IIRC, in C1 it's impossible to get rid off *all* sharpening. I thought you needed to run something like DCRAW to get truly unsharpened output.

 

Don't know ACR that well, but in C1 you can set sharpening to 0, and that doesn't turn it off. You can also (in 3.7.7 Pro, at least) find a check box that says "disable sharpening" in the alt-P preferences dialog box. That does turn off sharpening. I once used the Imatest black/white edge analysis tools to check this. There is about a half-pixel width difference in any edge when you go from "sharpening disabled" to "0 sharpening."

 

scott

[delander †]

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In C1 LE that comes with the camera you can disable sharpening on output in the preferences dialogue box. If you dont do this you get some sharpening even if the slider is set to 0 (all the way to the left). Even then, the amount of sharpening with the slider set to 0 depends on whether you have standard or soft look selected. The differences are quite noticeable.

 

I personally prefer some minor sharpening in C1, and do any final sharpening in PS if necessary.

 

Jeff

[jlm]

since raw is beeing discussed:

what camera settings are active when shooting raw? (mostly i am asking about white balance)

[sandymc]

what camera settings are active when shooting raw? (mostly i am asking about white balance)

 

The white balance settings are recorded in the DNG, but no adjustments are made to the actual image data. It's up to the raw processor to decide what, if anything, to do with the recorded setting....

 

Sandy

[cme4brain]

see the attached images. one is the original image resized and the other is a 100% crops of the focused area. sharpness was turned Off for the in-camera Jpeg, DNG file was converted with Photoshop with sharpening turned Off as well. everything else is default settings.

 

why is the Jpeg image so much more blurry than the DNG file? doesn't Jpeg processing just mainly involve figuring out the whitebalance, highlights, and shadows? i don't get how in-camera processing can make the raw image more blurry than it already was to begin with.

 

sorry if this is a stupid question. i'm not all that tech savy..

 

thank you!

 

JPEG compression, and therefore the quality of the image, greatly depends upong the camera. My P&S Kodak P880 (with a great 24-140mm Schneider lens by the way- better than several Canon L lenses to be sure) has such a good in-camera JPEG conversion that there is no NEED to shoot RAW with that camera- the images are the same quality. The Leica M8 JPEG compression is ESPECIALLY bad, and has been noted as such in several threads in this forum! Why Leica chose such a crummy in-camera JPEG conversion is beyond me, several $250 P&S cameras do a better job of it than the M8. There are several websites, DPREVIEW.com in particular, that note a 300line reduction in resolution via in-camera JPEG quality as opposed to DNG-toJPEG conversion via a photoeditor. That is a tremendous difference. I shoot DNG + JPEG.