Converted RAW to JPG Versus JPG

[kevinbythebeach]

Does anyone know if a Raw image converted to jpg with no other adjustments would look the same , better , worse, than an image shot in jpg ?

[JonathanC]

Just different, depending on your in-camera settings, but less fixable in PP later. The camera settings for such as white balance, sharpening etc are "set in stone" in the JPG.

[Colin Southern]

Does anyone know if a Raw image converted to jpg with no other adjustments would look the same , better , worse, than an image shot in jpg ?

It's one of those "how long is a piece of string" type questions. Most cameras "vary the JPEG" recipe depending on what the camera is set for; some wind it hard to do as good a job as the picture styles settings, whereas on the other hand it's also quite common for people to shoot with the picture styles still set to the last thing they shot, which may be totally inappropriate.

So in a way it's probably best to think of a RAW image as being a bit like all the ingredients needed to bake a cake, whereas an in-camera JPEG is always baked according to a specified recipe - whether or not it's the right recipe for the occasion is the big question.

Personally I'd be happy to have all JPEG modes removed from my camera, replaced instead with *.CR2 and *.DNG options.

[Raycer]

Hi Kevin,
What camera are you using?
RAW conversion depends on the program you use and your preference. Nikon, as an example use Capture NX or View NX. If you use the above Nikon softwares, jpg should come out the same as in camera processing. If you use Lightroom or other 3rd party software, the result will be totally different. I believe this also applies to Canon.

Agree with everything Colin said. I only use jpg option when I need to give the client picture NOW or there's no more memories for RAW files.

Ray

[SteveF]

I agree with Ray on the possible variables. Although a dedicated jpeg shooter I've experimented with RAW using various converters, PS CS2, Canon DPP, Rawshooter Esentials, etc and they've all had a different 'look' about them.

Being a Canon user I found the closest to a in-camera jpeg from RAW is the Raw Image Task software. It takes it's time (much slower than DPP) but near enough spot on to the jpeg from the camera.

Just to comment on Colins last paragraph: I love to experiment in-camera and really enjoy fiddling with those WB and Parameter settings. WB bracketing is one I find useful as you can have a warm and a cool frame from the one shot and hey! No effort ...

Anyway, RAW is no good to me - my Wife always tells me to shut up after I've asked her the 50th time 'does she prefer this tint to that ...'

[kevinbythebeach]

Well Its more a question i am trying to answer for a freind..I use canon .cr2 all the time and she shoots a nikon d40 and the only lens she uses is the bigma 50-500 first generation..
And actually the Sigma 50-500 first release is kinda crappy from what ive read and seen...
Just trying to narrow down her reasons for undetailed pics..she might even have her nikon set on small jpg..not sure..Nikon menus frustrate me... I think shes beginning to compare her lens agaisnt my L lens and getting frustrated...

[kevinbythebeach]

BUT HERE IS A FOLLOW UP QUESTION.......

Canons raw to jpg conversion versus using Photoshop to convert to JPG without any other changers just straight converion,,,,,one any better than the other besides just personal preferece???

[Colin Southern]

BUT HERE IS A FOLLOW UP QUESTION.......

Canons raw to jpg conversion versus using Photoshop to convert to JPG without any other changers just straight converion,,,,,one any better than the other besides just personal preferece???

Canon's DPP honours all the Picture Styles metadata tags (AFAIK), whereas ACR only honours the WB setting (and even that's only a starting point).

[SteveF]

BUT HERE IS A FOLLOW UP QUESTION.......

Canons raw to jpg conversion versus using Photoshop to convert to JPG without any other changers just straight converion,,,,,one any better than the other besides just personal preferece???

I 'think' the Raw Image Task in Zoombrowser does a better job of a straight conversion having done some tests last night. It seems to mimic the jpeg engine in-camera almost exactly and of course it gives you the option otherwise available to RAW shooters.

ACR seems to give a wider dynamic range but when shooting skin that's a bit wrinkled with age we don't need the shadows to be true! This is what I based my thoughts on.

[AlexB]

Besides color balance, raw conversion includes sharpening, some degree of noise reduction and color saturation. If you control the amount of sharpness and noise reduction you can squeeze most quality from yous shoots. I've been using Raw Therapee for the job because they don't apply any automatic noise reduction. On ACR some degree of noise reduction is always on, if your photo doesn't need, you are loosing good detail.
Cheers,
Alex

[Colin Southern]

On ACR some degree of noise reduction is always on, if your photo doesn't need, you are loosing good detail.

It caused one heck of a stink with one of the earlier versions of ACR - 5.1 or 4.1 off memory, but Adobe toned it down a bit after that.

Usually if you throw an unsharp mask over the image set to 300% @ 0.3 pixel for capture sharpening (in PS, not ACR) it'll come up looking pretty good as a starting point for further processing.

[crisscross]

Usual Nikon corollary from me

Nikon View NX (free) automatically does in preview of .nef (RAW) files what the camera might have done had it been set to .jpg or an auto mode, so totally unecessary to set camera to either .jpg only or .nef+.jpg. These View previews are sometimes quite difficult to surpass!...but once you have hand edited them in Capture NX2, ViewNX thereafter supersedes its first go with your latest.

[dan88]

Not sure if this is off topic, but tried to avoid posting a new thread but rather re-use one with similar info.

My question was whether RAW to JPEG conversion involves any loss of picture quality (as I have always shot in RAW ever since I was instructed by many people on this site to do so!) and one of my friends seems to think that RAW to JPEG conversion involves a loss of quality. I told him I'm sure this wasn't the case as to my understanding, RAW is 3 JPEGs combined - one for each channel (Red, Green and Blue) and thus wouldn't be any different as opposed to shooting in straight JPEG mode all the time. Someone please correct me if I'm wrong!

Thanks in advance!

[Colin Southern]

My question was whether RAW to JPEG conversion involves any loss of picture quality (as I have always shot in RAW ever since I was instructed by many people on this site to do so!) and one of my friends seems to think that RAW to JPEG conversion involves a loss of quality.

Yes there is a quality loss (or perhaps "loss of information" might be a better term), but I think that the real question should perhaps be "is the loss of information when a RAW file is converted to JPEG noticeable?" ...

... and that's something else entirely. In Photoshop you get to choose a quality setting ranging from 1 to 12; at a setting of 12 I'd challenge anyone to notice any quality difference between a RAW converted to a JPEG and one converted to a TIFF. Even quality settings of 10 are VERY VERY good.

The bottom line with JPEGs is that they're designed to throw away what the eye can't see, and compress what's left so that they're as small as possible - but - the downside is, because they're throwing away what they eye can't see, it's NOT a good idea to subsequently open one up and try to make big changes in levels etc.

In summery, they're great as a final output file format.

I told him I'm sure this wasn't the case as to my understanding, RAW is 3 JPEGs combined - one for each channel (Red, Green and Blue) and thus wouldn't be any different as opposed to shooting in straight JPEG mode all the time. Someone please correct me if I'm wrong!

Your wrong

RAW files consist of 3 greyscale images (for what of a better phrase), corresponding to information from the red, green, and blue channels. As part of the conversion these 3 groups of data are essentially combined into 1 image (with extra data added) - and that's what's available to save in - say - a lossless format like *.PSD or *.TIFF. These are the ideal formats for editing, but they're nothing like "3 JPEG images" I'm afraid; as mentioned above, JPEG images have large portions of the dynamic range discarded, many levels normalised (made the same) (where the difference is so subtle we couldn't tell them apart), and then the whole shooting match compressed, whereas RAW files contain all sensor info, although it is losslessly compressed.

[dan88]

Your wrong

RAW files consist of 3 greyscale images (for what of a better phrase), corresponding to information from the red, green, and blue channels. As part of the conversion these 3 groups of data are essentially combined into 1 image (with extra data added) - and that's what's available to save in - say - a lossless format like *.PSD or *.TIFF. These are the ideal formats for editing, but they're nothing like "3 JPEG images" I'm afraid; as mentioned above, JPEG images have large portions of the dynamic range discarded, many levels normalised (made the same) (where the difference is so subtle we couldn't tell them apart), and then the whole shooting match compressed, whereas RAW files contain all sensor info, although it is losslessly compressed.

Thanks for the reply

I'm not sure I'm completely wrong - as by 3 separate images, I was trying to say how photoshop separates the channels into red, green and blue - so I think I understood that part correctly My wording isn't the best at times though (although you've probably picked up on this from my previous posts!)

What you are essentially saying is that the loss of information would be the stuff that isn't seen by the naked eye, and depending on what level you export the images at defines how much the loss of information/picture quality will be? Please correct me if I'm wrong

[Dave Humphries]

Hi Dan,

Your friend is right, there will be a quality loss when you convert from RAW to jpg, it is inevitable. The question is, when do you want that to happen; when you click the shutter, or later, when you have had time to look at the image and assess what's really there?

I wouldn't really describe a RAW as "3 jpgs in one" it is much more than that, but yes you are correct in that it will contain separate information from the 3 primary (R,G,B) channels.
Think of RAW as a 'dump' of the almost pure sensor data, ready for later processing; it will have 12 or even 14 bits resolution in each colour (rather than jpg's 8 bits), and without many of the other things like noise reduction, sharpening, active lighting control, etc. that cameras do.
The benefit of shooting RAW and post processing (PP) is that you can vary the conversion to suit the picture content, this might be as simple as correcting over or under exposure by a stop or two, fixing the white balance, right up to spending hours dodging and burning to get the most dynamic range/least noise image from a single exposure (but this isn't "HDR").

However, if you shoot jpg, the camera made the jpg conversion from RAW when you took the shot and it (almost) irrevocably set the exposure and many other things mentioned above on the spur of the moment with whatever camera settings you had at the time, even if they were more relevant to the last shot you took.

People with film experience might like to think of it thus;
Shooting jpg is like shooting with Ektachrome (i.e. a transparency, or slide, film), if it's not right in camera, your options for post processing are (more) limited. Everytime you do something to a jpg picture, you should save as a copy because it will very likely reduce the quality further, and if you overwrote the original file and you don't like what you just did then
Shooting RAW is like shooting with Kodak Gold (i.e. a negative film stock for making prints from); before anyone sees it, you get a chance to perfect it in the darkroom, these days that'll be using the RAW convertor (Lightroom, DXO Mark, NX2, etc.)

Hope that helps,

[Dave Humphries]

I'm not sure I'm completely wrong - as by 3 separate images, I was trying to say how photoshop separates the channels into red, green and blue - so I think I understood that part correctly

Hi Dan,

To pick up on this statement, just because photoshop offers faders for Red, Green and Blue saturation doesn't necessarily mean it is working on the image in that format in the computer's memory.

Especially if jpg or in LAB mode, it will just do a lot of maths and change the picture file (in memory) to look like you; say, halved the red saturation, it doesn't mean there is a separate red image in memory that was halved in size, then output. From a user perspective, it really doesn't matter what format the image is in memory as long as all the knobs and buttons do as expected.

Here's a daft analogy I going to put in whether it's needed or not!
Think of it like a car, whether it's petrol, diesel, hybrid or electric doesn't matter when you're driving it down the road. All cars have accelerators and brakes, what goes on under the bonnet (hood) really doesn't matter. Just be sure to fill it up with the right 'juice'!

In other image formats like PSD or TIFF, it may well be there are separate R, G and B images stored and manipulated in memory, I don't know for sure, but particularly with the examples I gave above, I'd be surprised if it were done that way. Also, not all image editing progs work the same way internally, so others may differ.

Apologies if you knew this but I got the wrong end of the stick.

[Colin Southern]

What you are essentially saying is that the loss of information would be the stuff that isn't seen by the naked eye, and depending on what level you export the images at defines how much the loss of information/picture quality will be? Please correct me if I'm wrong

Your wrong! - Nah - just kidding

Your on to it, but - as Dave alluded to above - the JPEG conversion that I outlined is what's happening from a technical perspective; there's no guarantee that what it discards is what you want it to discard - that's why getting exposures pretty close when shooting JPEGs is a must.

[Colin Southern]

To pick up on this statement, just because photoshop offers faders for Red, Green and Blue saturation doesn't necessarily mean it is working on the image in that format in the computer's memory.

Photoshop represents the image "internally" using CIELAB as far as I know.