raw and jpeg

0141flyingv · 08-25-2008, 08:17 AM

hi can anybody explain raw and jpeg in basic terms to a complete novice, and why raw eats up your memory very quickly.

ftpaddict · 08-25-2008, 08:21 AM

RAW is the unprocessed data that your sensor receives. This presents us with several benefits: since the information is encoded in more than the standard 8 bit/pixel of the JPEG format, more tonal information can be extracted. At first this doesn't appear to be anything exciting, until you find out that you can gain up to one stop of exposure by working with levels and curves. This can be crucial in those shots where you can't afford to mess up.

The other important advantage of RAW is that the white balance setting on your camera becomes irrelevant, as you can change the white balance in post-processing applications such as Apple's Aperture, Adobe Lightroom, Silkypix etc.; without losing any detail or colour information.

The downside is that they're huge.

JPEG has none of what I have said above, but it is a considerable amount smaller.

Hope this information has helped. If anybody else has something else to add (or correct me if I'm wrong), please do so.

ManWithCamera · 08-25-2008, 09:29 AM

Good explanation, ftpaddict. I cannot think of anything to add,

Spex · 08-25-2008, 01:37 PM

I can

Since JPEG is compressed and processed, not only that you loose details due to compression, but with JPEG you also depend on in-camera processing. And most of the time it's just not good enough. Best example is K10D, whose JPEG's are crap if you compare them to his RAW converted JPEG's. You get MUCH MORE details and sharper image from RAW than from in-camera JPEG

**Adam** · 08-25-2008, 03:41 PM

Thread moved to the appropriate forum. Please keep in mind that the "Site Suggestions, Errors, and Help" forum is only for website-related matters! Thanks!

beaumont · 09-01-2008, 12:33 PM

Originally Posted by Spex

I can
Since JPEG is compressed and processed, not only that you loose details due to compression, but with JPEG you also depend on in-camera processing. And most of the time it's just not good enough. Best example is K10D, whose JPEG's are crap if you compare them to his RAW converted JPEG's. You get MUCH MORE details and sharper image from RAW than from in-camera JPEG

So, are you saying that a picture taken in Raw that is converted to JPEG via a post processing without any modifications at all, will turn out with more details and a sharper image than straight JPEG? (Hope I'm not hijacking?...)

Spex · 09-01-2008, 05:57 PM

Exactly, even with default settings in RAW converter, picture will be better quality thatn straight from the camera (at least from K10D). With some tweaking, you'll get MUCH better picture than from camera's JPEG.

Arpe · 09-01-2008, 07:15 PM

Plus if you edit jpeg, save, then edit agin, save - each time you save the quality of the jpeg is lessened. Jpeg is referred to as a "lossy" format, each time you save more data is lost and can't be recovered. Whereas if you keep the raw, when you edit it the settings you used to edit are stored and reapplied next time you open the raw file, but then you can change them and save another copy without degradation.

beaumont · 09-01-2008, 09:40 PM

As mentioned in another thread I've got going, I've just opened a raw shot in the Pentax Photo Lab software that came with the camera...saved it as JPEG...and can't honestly see an improvement over the JPEG that came out of the camera? Is this normal?...
thx

*Venturi* · 09-01-2008, 10:05 PM

This is about as succinct as I can come up with...

RAW is to film negative as JPEG is to Polaroid.

The caveat here being that JPEGs can be manipulated to some degree without serious quality deterioration.

*LaRee* · 09-01-2008, 10:28 PM

Originally Posted by beaumont

As mentioned in another thread I've got going, I've just opened a raw shot in the Pentax Photo Lab software that came with the camera...saved it as JPEG...and can't honestly see an improvement over the JPEG that came out of the camera? Is this normal?...
thx

It very well could be normal depending on the scene. I don't buy the *fact* that the k10d jpegs are not as good as raw files some_of_the_time. In Lightroom you can even pp your jpegs much as you do raw files. But if the image needs much pushing, you'll see the jpeg degrade a lot sooner than the raw file.
To me, the difference comes down to flexibility really. I shoot in raw because it provides me more flexibility in post processing. For some family events where I'm firing off a bunch of quick snaps, jpeg is fine on the k10d.

*mithrandir* · 09-01-2008, 10:31 PM

To make things a little simpler.
A RAW file is everything that the camera sensor saw saved to a file.
A JPG file is the RAW data processed. It can be processed in the camera or by Post Processing software. If done in camera (and the RAW file is not also saved) then you will have an abbreviated set of digital instructions for some device (usually a computer) to use to display the picture. If you did not have the in camera processor set correctly, then the picture will be of poor quality with little or no chance of correcting it.
If you take a RAW file and import it to Post Processing software in the computer, you have a lot more to work with it terms of data. It is exactly what the sensor saw and can be adjusted for exposure (within rather wide limits) and the white balance can be set correctly if the wrong white balance had been used in camera at the time that the picture was taken. Even though RAW files give you much more to work with, you still only get what the sensor saw. If it saw an out of focus, grossly under or overexposed image, all the software magic in the world probably cannot save the shot. In the case of under and overexposure however, you will have much more latitude for correcting the picture.

Arpe · 09-02-2008, 07:25 PM

Originally Posted by beaumont

As mentioned in another thread I've got going, I've just opened a raw shot in the Pentax Photo Lab software that came with the camera...saved it as JPEG...and can't honestly see an improvement over the JPEG that came out of the camera? Is this normal?...
thx

That would be normal for a well exposed shot and the camera is set to process the data the way you like it.

kerrowdown · 09-10-2008, 06:00 PM

Just shoot in raw and buy more memory cards, just think back to the film days as to how many rolls you bought. Then you couldn't reuse the same roll again like you can with memory cards.