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Thread: Two questions about working on raw files

  1. #1

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    Two questions about working on raw files

    I have some questions about working on raw files. Before I always take photo with jpg file directly generated from my 400D, the average size of such file is usually between 2MB - 3 MB. Then I use Photoshop to work on this file.

    Now I like to take photo with raw file output and use canon DPP tool to convert the raw file into a jpg file.

    I have looked two different jpg files - one from DPP generation and one from 400D generation directly.The size of DPP jpg file is much bigger than the one from camera's, for example, a 400D output jpg file of size 3MB, the corresponding DPP's jpg size is about 8 MB.

    Now I come across two questions:

    (1) when I look at DPP jpg file closely, it shows more noise than the
    400D jpg file. What is the reason?

    (2) Should I apply Photoshop to the jpg file generated DPP?
    I asked this because I think Photoshop cannot directly apply to raw file. But I may be wrong.

    Thanks in advance.

    Yan

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    Re: Two questions about working on raw files

    Hi Yan,

    I'm about to go to bed, so will spend more time on this tomorrow with you, but in the meantime, can you please tell me what camera you're using, and what version of photoshop you have?

    My first couple of thoughts that come to mind is that the in-camera generated JPEG will be processing the image according to the JPEG quality and picture styles settings, whereas DPP may be set to ignore these settings.

    My personal preference is to convert all RAW files to Adobe's DNG format so that they can be opened in any Photoshop CS version, and to do away with DPP altogether; the latest versions of ACR (Adobe Camera RAW) (CS3 and CS4) are VERY powerful.

    Hope this is at least a small start. And again, welcome - great to have you with us here!

  3. #3
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    Re: Two questions about working on raw files

    Quote Originally Posted by Yan Zhang View Post
    I have some questions about working on raw files. Before I always take photo with jpg file directly generated from my 400D, the average size of such file is usually between 2MB - 3 MB. Then I use Photoshop to work on this file.

    Now I like to take photo with raw file output and use canon DPP tool to convert the raw file into a jpg file.

    I have looked two different jpg files - one from DPP generation and one from 400D generation directly.The size of DPP jpg file is much bigger than the one from camera's, for example, a 400D output jpg file of size 3MB, the corresponding DPP's jpg size is about 8 MB.

    Now I come across two questions:

    (1) when I look at DPP jpg file closely, it shows more noise than the
    400D jpg file. What is the reason?

    (2) Should I apply Photoshop to the jpg file generated DPP?
    I asked this because I think Photoshop cannot directly apply to raw file. But I may be wrong.

    Thanks in advance.

    Yan
    I had a 350D for a year and used DPP most of that time.

    The camera auto jpg generation will be choosing its own machine-safe pre-sets (if you are using scene types, each a bit different) and a high degree of compression.

    When you use the RAW pane in DPP you can make decisions 'worse' than the presets. Don't be tempted to sharpen above say 6-7 as sharpening the whole image generates noise in plain areas. It is best to sharpen only the areas actually needing sharpening in PS later.

    When you 'convert & save' you will see there is a quality slider and if you leave it at 10 it will generate a much larger image than at say 7-8 which is probably fine. Also it is pre-set at 350dpi and 300 is plenty.

    However, you will see in the 'tools' menu that you can transfer the image direct to photoshop. That will probably be as a .tif image, much larger still, 25MB±. But if you are intending to do serious editing, you need to do it on .tif which is a 'lossless' format, whereas every time you save or transfer a .jpg there is some loss of original content.

    The decision you need to make is whether you need to go out of DPP at all. For well exposed images of subjects with good colour range, maybe you don't. You can print from DPP, excellent page layout, & a re-saved CR2 file takes in your edit (and gives you a choice to revert to last saved & original). For forum & screen jpgs, in the 'convert & save' you can set size to (suggest 1024 max width and or 768 max height) and at quality 7 get a file of around 300kb.

    If you can't get a decent image using only the RAW pane, and may be tempted to play with RGB pane, you probably best go to PS.

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    Re: Two questions about working on raw files

    Colin and Crisscross

    Thanks very much for your help.

    I use 400D camera, and my Photoshop is CS2, 8.0 version.

    This morning I have tried to transfer the raw file into PS, and save it in both format .PNG and .tif.
    Then I can apply PS functions to edit these files. Both of them are of 46 MB and 57 MB while the 400D
    generated .jpg is only 3.5 MB.

    But when I look at .PNG or .tif files, and compare them with the 400D generated .jpg file, they still show more noise. Why? In which way I can eliminate such "noise"?

    Another question: when I open a .tif or .PNG file in Photoshop, after doing editing, hw can I save it in a
    .jpg file? It seems that when I click "save as" in Photoshop, there is no option item for format .jpg.
    Last edited by Yan Zhang; 31st January 2009 at 01:27 AM.

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    Re: Two questions about working on raw files

    Hello Yan, welcome,

    If I'm thinking along the right lines (I'm a Nikon user, so forgive me if this is rubbish!) but I'm assuming that you are sharpening your RAW file when you convert. Don't. Turn this option off entirely, as all it does is overall sharpening and this includes all the noise in all channels. When Colin wakes up he'll put you right!

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    Re: Two questions about working on raw files

    Quote Originally Posted by Yan Zhang View Post
    This morning I have tried to transfer the raw file into PS, and save it in both format .PNG and .tif. Then I can apply PS functions to edit these files. Both of them are of 46 MB and 57 MB while the 400D generated .jpg is only 3.5 MB.

    But when I look at .PNG or .tif files, and compare them with the 400D generated .jpg file, they still show more noise. Why? In which way I can eliminate such "noise"?
    Hi Yan,

    You're welcome.

    My first suggestion is to save your files in Photoshop's native PSD fomat - it supports all of the structures that Photoshop uses (layers etc), but files are around 30% small than *.TIF files. However, if the size of the files is a problem then *.JPG is still a good option if you don't want to re-edit the files too much (JPEG files lose quality each time you save them after making changes).

    The reason that JPEG files contain less noise that RAW files is that the in-camera RAW -> JPEG converter/processor is doing noise reduction for you (along with sharpening the image / adjusting white balance / adjusting levels / adjusting saturation / adjusting contrast etc etc etc). RAW -v- JPEG is a bit like having the ingrediants to bake a cake -v- buying a cake that's already made; in the first instance since you bake it yourself, you get to decide how you want it to taste, whereas with the bought cake (JPEG), the only control you have over the outcome were the few brief instructions that you gave to the cheif before hand (picture styles). In a JPEG / Picture styles scenario this includes noise reduction.

    On the face of it you might think that this is a "win" for JPEG in that you're getting small & cleaner-looking files straight out of the camera, but with many things in life there is a trade-off; in this case those smaller files must (by definition) contain less information - and the more agressive the noise reduction, the less sharp the file (same goes for the JPEG quality setting). So JPEG images may look just fine for what you're wanting, but when push comes to shove, a correctly processed RAW image will win the ultimate quality test everytime, although the caveat to that is (a) you have to know how to process RAW files correctly, and (b) in many cases the differences may only be apparant "under a microscope" and not readily apparant with 2 printed images side by side. Personally, I prefer RAW because it keeps all captured information, whereas JPEG throws a lot away, AND compresses the image using a lossy algorithm.

    So the bottom line is "if you're happy with the JPEG images right out of the camera then that's great - job done" - however, if you'd like more control over the finished image (control that you can't get from tweaking the picture styles & JPEG quality settings) then RAW is the way to go (where you can specify the amount of noice reduction that you want in addition to a WHOLE lot of other parameters. Personally, I'd be quite happy to have JPEG capability removed from my camera altogether (to have it replaced with a DNG option would be ideal) becuase I have to push my images hard, and JPEG just wouldn't cut it for wide-dynamic range sunrises & sunsets - but - neither option is inherantly right or wrong - they're just there as options so people can choose what's right for them: the "best of both worlds" to coin a phrase :)

    To answer your question about RAW noise reduction ... you really have several option ranging from photoshops built in noise reduction tools FILTER -> NOISE menu to specialist 3rd party plugins like noise ninja - but noise reduction can be a whole new thread :)

    Another question: when I open a .tif or .PNG file in Photoshop, after doing editing, hw can I save it in a .jpg file? It seems that when I click "save as" in Photoshop, there is no option item for format .jpg.
    When you open the files in the CS2 RAW converter, down the bottom of the screen there is an option to set whether you open the files in photoshop as 8 bit files or 16 bit files - if you open tham as 16 bit files they'll be twice as big, but there's less chance of damaging the image if you're doing large level adjustments ... however ... you can't save a 16 bit file as a JPEG - so before you save it as a JPEG copy, you first need to choose IMAGE -> MODE and set it for 8 bit. Whilst you're there, you also need to choose EDIT -> Convert to Profile (NOT ASSIGN PROFILE) and convert the image to sRGB if you're going to display the image online or have it printed). Once you've changed the mode of the file from 16 to 8 bit then the save as JPEG option will be available. If you want to tell the RAW converter to spit out an 8 Bit sRGB file then you can do that too, which in terms of "safety" is fine so long as you're not making large levels adjustments.

    Does this help?

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    Re: Two questions about working on raw files

    Hi Yan Zhang
    welcome to the forums.

    I've also come across the 'how to deal with RAW/Jpeg choice' too.
    And after some readings (and advices from pros here ), I worked out a workflow suitable for me.

    Basically, I just transfer my RAW and process them in Lightroom, however (I don't know with DPP) I turn off the sharpening option and leave it for Photoshop.

    I export the processed RAW in Tif format to work them in Photoshop, where I do sharpening and further CC; and also a friend was kind enough to help me with NoiseNinja to deal with noise.
    At the end I resize and save the final image as JPEG for web sharing.

    Like you, I was tempted of working with JPEG, which is seriously perfect for presentations and web sharing. However, I learned and thought that it may become a problem if, for some reason, I want to print the photos.
    This is why I decided to adopt RAW shooting to be safe and future-proof.

    So briefly,
    RAW -> Shot in camera. Transfered and backed up to DVD
    DNG -> Stored in computer and processed with Lightroom
    Tif -> Stored in computer and worked with Photoshop
    Jpeg -> Stored in computer and shared on the web

    祝您好运!
    Last edited by Colin Southern; 31st January 2009 at 04:30 AM.

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    Re: Two questions about working on raw files

    Dear Chelseablue, Colin and Zephyrize,

    Thanks so much for all of your kind helps. Now I got basic ideas of how to deal with raw files.
    I'll do some practice now.

    非常感谢!

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    Re: Two questions about working on raw files

    You're welcome Yan - just be sure to pop back often and show us what you've been shooting eh?

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