Lossless JPEG?

[DocFrankenstein]

I've heard about it. There's some version of the lossles jpeg out there.

Which one is it? Does the rebel have it?

And btw: Do RAW files use lossless compression of some kind?

[CyberDyneSystems]

Can't answer the jpeg question other than to say that I understand that the data you "squish" out of a jpeg ain't ever coming back.. thus it is "lossy"

The second part though.. yes RAW files (most anyways) incorporate compression that is NOT lossy.

[Scottes]

Yes, there is.

JPEG 2000. No.

Yes.


Not much else to say, really...

[Olegis]

You can find some info regarding the lossless JPEG here (http://www.faqs.org/faqs/jpeg-faq/part1/section-13.html). It's old, non-practical and not used in any way we would care about.

[DocFrankenstein]

I see. Thanks for the link olegis.

RAW would be the only way to go then.

[Olegis]

That depends, of course, on what (and for what purpose) you're gonna shoot. I shoot 99.9% Large JPEG, but some of my images (http://www.pbase.com/olegis/lahav&page=all) were shot in RAW. Recently I made 3 enlargements (60x40cm), two of them were from RAW and one was from JPEG - the quality difference was barely noticable, if any.

[DocFrankenstein]

I meant if you want lossless compression. Unlike with S1 IS I can't find any Jpeg artifacts in my images unless I upsize or curve them too much.

I'd want to shoot raw if:

1) I print something larger than 8*12
2) I expect to edit my images somehow

You never know...

But I just can't shoot raw. I have 256 mb card. :lol:

[Adam Hicks]

I do work with the district attorney's office and RAW / lossless images are important for legally defensible evidence. We're doing a big storage setup for a county here in D/FW using terabytes of RAIN storage. I won't get into the details, but lossless compression rears it's head now and again!

Adam

[Olegis]

Well, I feel you ... I have two 256MB cards, and those 28-30 pictures for a single card just kill me every time I come to shoot RAW. :(
Have to get a bigger card ...

[DocFrankenstein]

I do work with the district attorney's office and RAW / lossless images are important for legally defensible evidence.
:shock:

This is really good that you brought it up. I'd never thought about this way.

It could be argued that the actual object on the picture is a "compression artifact"... unless it's really detailed and take up half the frame :lol:

I'll keep that in mind if I ever have to photograph for legal stuff.

[DocFrankenstein]

Well, I feel you ... I have two 256MB cards, and those 28-30 pictures for a single card just kill me every time I come to shoot RAW. :(
Have to get a bigger card ...
Yeah... a friend of mine had sent me a link where a 2 gb microdrive was for 70-80 bucks. I lost it :(

[Olegis]

I do work with the district attorney's office and RAW / lossless images are important for legally defensible evidence.

Well, that makes sence ! After all, you can't edit and actually save a RAW file, can you ? Good point, Adam.

[Adam Hicks]

Right... there's also ways of adding an encrypted wrapper around images and using a USB dongle to guarantee authenticity. I am consulting on a project to archive all crime scene images, DWI videos, confession audio, etc for 10 years per item. If someone breaks probation and has to be re-tried, the city / county has to pull the evidence from the original trial. Fun stuff!

Adam

[Cadwell]

I do work with the district attorney's office and RAW / lossless images are important for legally defensible evidence.

Well, that makes sence ! After all, you can't edit and actually save a RAW file, can you ? Good point, Adam.

Yes, of course you can. Any form of digital data can be edited. Whilst I don't know of an application capable of editing Canon RAW files it doesn't mean that it doesn't exist nor would would it be hard to create one or modify an existing application to do so. Not hard at all...

I certainly wouldn't be happy with someone using digital camera images as any form of "proof".

[Andy_T]

Yeah... a friend of mine had sent me a link where a 2 gb microdrive was for 70-80 bucks. I lost it :(

Sounds interesting ... unless it is a 2.2 GB microdrive :cry: (which is just what I suspect)

Best regards,
Andy

[ron chappel]

You can find some info regarding the lossless JPEG here (http://www.faqs.org/faqs/jpeg-faq/part1/section-13.html). It's old, non-practical and not used in any way we would care about.

Er..not sure how old that link is,but it sure is out of date :shock:

There is a new standard in the making-jpeg 2000.Do a google search and you'll find the official website and more than enough explanitary details.

In summary, i don't think it's entirely lossless as scottes states (it's abit tricky reading through the masses of info). The benifits over normal jpeg are:
better images at highest quality,
better images at lowest quality,
Plus it has a whole bunch of usefull minor features that i won't even try to go into

Normal jpeg is still the best at intermediate compression levels it seems

[Scottes]

In summary, i don't think it's entirely lossless as scottes states...

From http://www.jpeg.org/faq.phtml?action=show_answer&question_id=q3d5bc070 1c9b6

"JPEG 2000 is the latest series of standards from the JPEG committee. The original standard for digital images (IS 10918-1, popularly referred to as JPEG) was developed 15 years ago, and with the major increase in computer technology since them, and lots of research, it was felt to be time for a new standard capable of handling many more aspects than simply making the digital image files as small as possible. JPEG 2000 uses 'wavelet' technology. and as well as being better at compressing images (up to 20 per cent plus), it can allow an image to be retained without any distortion or loss. Simply sending the first part of such a 'lossless' file to a receiver can result in a lossy version appearing (like present JPEG) - but continuing to transmit the file results in the fidelity getting better and better until the original image is restored."

[ron chappel]

Thanks scottes

That description sounds abit like progressive jpeg but better.Nice

Pity it may not make much headway in general use as normal jpeg is so entrenched

[DocFrankenstein]

Yeah... a friend of mine had sent me a link where a 2 gb microdrive was for 70-80 bucks. I lost it :(

Sounds interesting ... unless it is a 2.2 GB microdrive :cry: (which is just what I suspect)
I am not sure. It's green though. :? (the outside of the memory card is green)

[RichardtheSane]

Yeah... a friend of mine had sent me a link where a 2 gb microdrive was for 70-80 bucks. I lost it :(

Sounds interesting ... unless it is a 2.2 GB microdrive :cry: (which is just what I suspect)
I am not sure. It's green though. :? (the outside of the memory card is green)

That would be the Magicstor then.

Run away. Fast

They are unreliable, slow and generally poor quality. Get what you pay for, only with those you dont even get that much.

[DocFrankenstein]

Cool. TY.

[Cadwell]

Actually, Richard understates things. Magicstors are the work of the devil. You'd be better off not taking any shots because then you won't feel the pain when the magicstor loses them.