View Full Version : Raw vs JPEG

05-23-2005, 10:20 AM
Raw vs JPEG. Can someone explain this in laymans terms for me. Is there a benefit of one vs the other. I noticed the DSLR rebel I just got will shoot in both, but I have no knowledge or experience with RAW. If I shoot in that will i have to convert everything in order to print them at the local shop? special software?? I curently hava PSP 9.0 and Photoshop 7.0. Any info and Ideas are much appreciated.

05-23-2005, 11:48 AM
RAW - You take a picture. The camera captures the data from the sensor and stores it in a buffer. It may or may not compress this data (the D70 does), but if it does, this is the ONLY time it ever gets compressed. It then writes all this information to a file on the storage media (the D70 uses CF card), attaching to this file some extra data called the meta data. The meta data contains all the settings you used to take the picture.

Anytime you view the picture, you need a RAW file viewer/editor. This program applies metadata to the picture and displays it, without changing the RAW sensor data. You can alter meta data settings to change how the picture looks, and this does not make any change to the RAW sensor data. You can save the changed meta data without altering the RAW sensor data. If you display the image in the camera, the camera applies the meta data just as a separate program would.

PSP 9 has a RAW editor/viewer built in for a number of different cameras, including the D70.

JPG - You take a picture. The camera captures the raw sensor data as before, but it then submits the raw data and meta data to a program in the camera that converts the file to JPG format and saves it to the storage media. This results in the advantage of a file that is much smaller, because JPG files are compressed. However, now you take the JPG file to your computer. Open it and save it many times without making any changes. You will have degraded the image, because every time you save a JPG, it compresses the current version. Each compression degrades the image a little bit more. It's not really as bad as it sounds, because the JPG algorithms are pretty good. JPG is convenient and compact.

You can always convert a RAW file to JPG. You cannot convert a JPG to RAW (Possibly not 100% accurate). You can convert a JPG to TIFF (a lossless format), but TIFF files are HUMONGOUS (huge doesn't quite cover it).

This is why I shoot RAW. If I need a JPG, I convert it.

I kept mentioning the D70. Only one reason. That's what I have, so that's what I know.


05-23-2005, 01:05 PM
Thank you so much for giving me the basics and low down on this. i knew jpegs were compresed files, but i never knew that they degraded as you said. Thanks for the reply

05-24-2005, 07:53 AM
You are welcome.

Perhaps I overstated the case. With my D70, you can take Large, Fine JPG and probably save at least 10 times without really noticeable degradation. That's probably more times than you will open the file to edit it.

Also, you can do all the same manipulations to a photo in JPG that you can do in RAW, but you do them directly to the image, not to metadata. Also, the tools are called by different names. The difference for me is never altering the RAW data itself and I also find the Nikon Capture editor so much more intuitive in terms of making my edits, because the tools are largely the same as on the camera.


05-24-2005, 08:48 AM
Eric thank you so much. You are right. Generally for me if I edit a pic I open it once and Im done. And for the most part I am just shooting pics of daily life with my kid or hubby. i am going to say that when I take a pic since it is just family photos they are left alone and fine as is. When I do edit a picture though, 95% of the time it is to do something like this that is just fun. My parents enjoy seeing fu-fu stuff like this via email.



05-24-2005, 11:44 AM
How cute Monica!
I am glad you are puttin' that camera to good use. ;)

I shoot RAW + JPEG and about 85% of the time I keep the JPEGS only. But the other 15% the RAWs save the photo from being rubbish.

05-24-2005, 03:31 PM
This (http://www.luminous-landscape.com/tutorials/understanding-series/u-raw-files.shtml) link has a lot of great info on Raw files.

05-24-2005, 03:57 PM
Great picture, Monica! "Barefoot Boy with cheeks of tan (or rose!)"