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I'm having a little difficulty grasping the concept of shooting 'raw'
I should first point out that I am in the market for my first DSLR which will be a Canon D40. I say this just in case it helps answer my question in any way..

From what I understand, shooting raw means capturing the data from the sensor but not converting it to an image. Would you then have to download the files to your computer to convert them? What benefits / disadvantages are there from shooting raw? Why does one have to process the image? Doesn't the camera do that for you? What would you actually be controlling by processing it? I'm really confused about this raw stuff..

I'm coming from a world of transferring images directly to my PC and there you have it..

Thanks in advance for your help...

Comments (18)

When you take a photo your camera will normally do a bunch of things to contert the light it gathers into an image..

This'll be along the lines of1) Gathers all the data raw from the CCD.

2) Does white balancing (trying to adjust colours so that you get the right tones under different shades of light, eg sunlight vs incandescent)3) Converts the image into a compressed JPG.

By taking RAW mode images you're saving the data from step 1 to the card directly..

The main advantage of doing this is that the camera is normally in a hurry to convert to JPEG so that it can get back to shooting the next shot rapidly, and JPEG is a lossy conversion, so there's no way to get back all of the original data. If you're taking pictures in low light or high ISO this may lead to all sorts of digital noise in the image..

By shooting in RAW mode you have the option of doing the RAW->JPEG (or RAW->TIFF/PNG etc etc) conversion on a machine with lots of processing power and time where you can fine-tune aspects of how the JPG is encoded and how colour tone/white balancing is done..

The downside of RAW mode is that the raw images themselves are proprietary (so you can't normally share them directly unless other people have a raw image decoder that suits your format) and are also quite huge (fewer per picture card, may take longer to write to the card)..

Hope that helpsFuji S6500fd newbie..

Comment #1

When a RAW image is processed, parameters such as white balance, contrast, tone, saturation, and sharpening are applied to the data to produce the jpeg file. If the camera does this, then it does it according to how you have set the parameters. But what happens if you had one of the parameters, e.g. white balance, set wrong? The image will look bad, and it wil be extremely difficult to correct the jpeg file after the fact. Also, the camera may not process the files to your taste. When you process the RAW files yourself on your computer, you are in full control.



Your camera will allow you to shoot RAW+jpeg. This gives you two files for every image, the RAW file plus the camera-produced jpeg. If the jpeg comes out looking good, then use it. If not, then you've got the RAW file from which to salvage the image (if it's not too bad)..

By the way, I assume you meant the Canon 40D, not the Nikon D40...

Comment #2

Can someone explain why you cannot do the same changes to a jpeg image that you can do to a RAW image? I mean some of the things in post processing you guys are doing to a RAW image can be performed to a JPEG imge in PS. So, why do you guys say that it cannot be changed on a JPEG vs. a RAW file? Can some please explain this. I am having a hard time understanding this. Could it be that it can be done to a JPEG file but at the expense of something else causing the same picture with the same parameters to look different because of it being a JPEG vs. RAW? I am lost...

Comment #3

Niceguymr wrote:.

From what I understand, shooting raw means capturing the data fromthe sensor but not converting it to an image..

Shooting raw means that the sensor data is not converted to a jpeg image in the camera; rather, only the raw data is saved. The camera will still show you the image on the LCD display, but it will not have converted the data to a "finalized" jpeg..

Would you then have to.

Download the files to your computer to convert them?.

Yes, once you transfer the files to your computer, you can edit them, and save as a jpeg or tiff with a raw converter..

What benefits /.

Disadvantages are there from shooting raw?.

You can adjust many more settings and obtain better results by shooting raw. It is a loss-less format, meaning it keeps all the data straight from the sensor, unlike a jpeg conversion, where the image gets compressed by eliminating some of the sensor data to make the file smaller. What this means is that if you have clouds that are blown (too bright, no detail), with raw, all the original data is there to recover most of the details of those clouds (unless you totally overexposed the picture). With a jpeg, most of that original detail data has been eliminated in the jpeg compression, keeping only what was most visible (the white detail-less color), so trying to recover that detail is just not possible because it's no longer there..

You'd be surprised how much detail you can recover from dark and light areas in your pictures with raw. Of course, you wan't to get as close as you can to the right exposure when you shoot your picture, as this will give you the maximum detail..

Jpeg is an 8 bit format, which means it has 256 colors to mix and work with. Raw images are in 12 bit format, which means it has 4096 colors to work with, so colors are richer and color transitions are smoother, and you also edit in 12 bit, this is another reason you can edit more aspects of the picture in raw..

Also, you can change the white balance and even adjust actual exposure to a certain extent. The white balance is how your sensor reacts to the colors in your image composition. This can be changed because you are editing the actual data (what makes the image). It's like changing your white balance in your camera before you took the shot..

Don't be afraid of the raw format. You can view your raw pics even with Windows Explorer with a microsoft plugin. And there are plenty of free raw viewers you can use prior to editing them and saving them as jpegs..

And it is easy to save them as jpegs. Raw editing is not daunting either, some photos won't even need any editing if you think they look fine in your editor. Your raw editor can then batch save all your raw files to great looking jpegs after (or with no) raw editing..

Hope this helps..

Albert-O.

Http://www.berto.zenfolio.com.

Image control:Zoom outZoom 100%Zoom inExpand AllOpen in new window..

Comment #4

Shutterman wrote:.

Can someone explain why you cannot do the same changes to a jpegimage that you can do to a RAW image? I mean some of the things inpost processing you guys are doing to a RAW image can be performed toa JPEG imge in PS. So, why do you guys say that it cannot be changedon a JPEG vs. a RAW file? Can some please explain this. I am having ahard time understanding this. Could it be that it can be done to aJPEG file but at the expense of something else causing the samepicture with the same parameters to look different because of itbeing a JPEG vs. RAW? I am lost..

When the raw sensor data gets converted to a jpeg image, it is compressed. During this compression, certain data gets deleted (this is how it gets compressed). I will use a dark shadow example. If you have a rock with a dark shadow underneath it (let's say... hiding a spider in there somewhere, but the exposure is too dark), a jpeg conversion process will analyze that area of the picture, and think, "OK, it's black, so I will eliminate most of the colors in that area that are not black, or near black. So that other data is gone.

No way to get those original pixels back, because they've been tossed out. So if you lighten up that area in a jpeg editor, you will mostly get... a lighter black color with not much detail in shades or color..

Now, a raw file since it is not compressed will still contain all the other little color and gray shades pixel info in that dark area, so if you want to lighten up that area to reveal those little color pixels (detail), you can still do that, and bring out those details because they are still there, it's just that the exposure is too dark - but you can adjust the exposure, just like in-camera (to a certain extent)..

Also, with jpeg, you are working with 256 colors (8 bit), where as with a raw file, you are working with 4096 colors (12 bit), so more color detail and smooth color transition is possible. Have you ever seen a picture of a sky where the color transitions are not smooth? There are definite lines where the shades of blue change? This is because there is not enough detail data in the image to create a smooth transition. It is either one shade of blue or another, no in-between, because that in-between color data has been lost..

Any pro's out there, please correct any technical information or explanation I may have screwed up .

Thanks,Albert-O.

Http://www.berto.zenfolio.com.

Image control:Zoom outZoom 100%Zoom inExpand AllOpen in new window..

Comment #5

Shoot in RAW, and you have all the PP info you can get from the photo..

Shoot in Jpeg, you will not have the same control, in fact much less.

Shot Raw for pro images.

Shoot Jpeg for day to day images.

Shoot me if i'm wrong.

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Mike Rudge..

Comment #6

The comments above pretty much cover the ground.I will point out that there is no pressure to shoot raw..

You've been shooting jpegs up till now and you can continue to shoot jpegs with your new camera. A lot of people shoot mostly jpeg. This is particularly true of sports shooting where you are trying to get off multiple shots per second. Jpegs allow much faster thruput to the card. As long as you are reasonably careful with exposure and white balance the pictures will look great..

A member of the rabble in good standing...

Comment #7

LM1 wrote:.

...A lot of people shoot mostly jpeg. Thisis particularly true of sports shooting where you are trying to getoff multiple shots per second. Jpegs allow much faster thruput tothe card....

So when the specs on the 40D says it shoots "6.5fps or 3 fps up to 75 JPEG" images, which number refers to shooting raw? And why are there 3 different numbers instead of 2?..

Comment #8

Think of car seats..

RAW is some twenty-way heated and cooled tilt, twist, lumbar support, front, back, high, low seat..

JPEG is like having a seat you can move forward and back, tilt the back of, tilt the front of the seat up under your knees, and probably lift a bit higher so short people can see out, or lower, so women from beer commercials can wear their cowboy hats..

So, yes, a great deal of change can be done to a JPEG file using Photoshop, Photoshop Elements, etc..

But if you really, really messed up the original shooting, RAW lets you fix it even more. Or, for that matter, lets you skip trying to do it right in the camera, because you know you can repair it later..

With both RAW and JPEG, you do need to get the door open and climb into the car and point it int he right direction, regardless of the seat..

BAK..

Comment #9

RE>"6.5fps or 3 fps up to 75 JPEG" images,<.

I don't know what you mean by three numbers instead of two, but as for the numbers in quotes....

You can set the camera's "motor drive" so it takes 13 pictures in two seconds that's 6.5 per second or 3 pictures in a second. Depending on what you are shooting, you might want the tiny differentces beftween frames that come with 6.5 fps, or you might be happy with "only" three shots in a second. Among other reasons, how fast can your flash work?.

The 75 is the total images that fill the buffer as you shoot, and is approximate. Depending on how fast your memory card is, more or fewer shots will go into the bffer and then into the cardwhile you hold down the shutter release..

Regardless, Canon seems to think the 75 is a fair number,.

Why anyone would need 75 shots taken over twnety seconds is beyond me, however. This is technology for the sake of technology..

BAK..

Comment #10

Shutterman wrote:.

Can someone explain why you cannot do the same changes to a jpegimage that you can do to a RAW image?.

There are two issues. First, most jpg processing only uses a portion of the brightness range captured by the camera. In my camera, the brightest jpg is about a stop less bright than the brightest available using raw. For a lot of photography, it is not a big deal but if you have a scene with a large brightness range, the extra stop can sure help get a better image. By shooting to the right an extra stop can provide significant improvements in the shadow areas..

The second issue is that jpg processing converts the number of possible values for each color to 256 rather than whatever the raw data has (up to 4096 on my camera). Thus jpg does not have many tone values in each color channel to work with and the amount of adjustment is limited particularly in the shadow areas. Put another way, raw processing with it much larger number of tone levels per color can take much more adjustment without any unwanted artifacts, banding, etc. showing up. It is fair to say that the main limitation to jpg comes from the truncation to 8 bits per color than from the other features of jpg processing.Leonhttp://homepage.mac.com/leonwittwer/landscapes.htm..

Comment #11

Do most DSLR cameras come with the necessary software to convert raw images to JPEGs?..

Comment #12

I might as well throw in my 2d worth: RAW is very usefull at times but can take a while to post process and learning it can take a long while. JPG's are more than adequate for most people most of the time and so - as I see it - RAW is a tool you use when the scene in front of you is going to be difficult. A good example is an unevenly lit subject with many highlights and deep shadows..

BTW, no one seems to mention this but saying "compressed" covers a multitude of sins. Some cameras compress a lot or else a medium amount and others can be set to compress very little; so you get a decent jpg and wonder why they bother with TIFF's and RAW. F'instance the camera I'm thinking about (5 megapixels) turns out jpg's of about 4,000 KB (called SHQ) and RAW files of 9697 KB. Others compress a lot more and I understand why people ask this question over and over again and complain about jpg quality ..

BTW (2), my jpg's are 16 million colours and have been for the last ten years..

Regards, David..

Comment #13

I believe so but the quality and usefullness of the software varies considerably. A common complaint about camera manufacture supplied software is it is often pretty slow compared to third party alternatives. The quality thing is in the eye of the beholder.Leonhttp://homepage.mac.com/leonwittwer/landscapes.htm..

Comment #14

This thread has a lot of good info - thanks everyone!..

Comment #15

David Hughes wrote:.

BTW (2), my jpg's are 16 million colours and have been for the lastten years..

The references in earlier posts to 256 colours are per channel, so altogether 256 x 256 x 256 = 16.7m...

Comment #16

Steve Balcombe wrote:.

David Hughes wrote:.

BTW (2), my jpg's are 16 million colours and have been for the lastten years..

The references in earlier posts to 256 colours are per channel, soaltogether 256 x 256 x 256 = 16.7m..

What I read was "with jpeg, you are working with 256 colors (8 bit)... " but I won't argue..

Regards, David..

Comment #17

David, you're right; I guess I did word that incorrectly - sometimes the mind jumps ahead, makes assumptions and omits details. I thought I had read that through to make sure it made sense .

It is 256 colors for each channel (Red, Green, Blue) to mix and work with in jpeg..

4096 per channel to work with in raw..

Thanks for pointing that out..

Albert-O.

Http://www.berto.zenfolio.com.

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Comment #18

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This question was taken from a support group/message board and re-posted here so others can learn from it.

 

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