Results 1 to 9 of 9

Thread: 'Pixel semolina' in image from RAW

  1. #1

    Join Date
    Feb 2011
    Location
    Paris region, France
    Posts
    129
    Real Name
    Chris

    'Pixel semolina' in image from RAW

    Hello everyone,
    I'm very new to RAW processing. This question may be dumber than dumb, but please bear with me.
    People on a different thread advised me that I'd really see the advantages of RAW in extreme lighting conditions, so I pointed my G11 out of the window at Orion : 1" @ ISO 1600 f4.5 (as wide as it'll go at 5x).
    Result from PSE-9 in jpeg at quality 12 (Orion's belt and sword in a highly light polluted area)
    Native JPEG on left, RAW on right
    'Pixel semolina' in image from RAW
    No 'artefacts' from the RAW, the leaves on the laurel tree look crisper... but... the stars stand out better in the JPEG, and the background on the RAW file looks like semolina.
    What am I missing ? What should be my first approach in taking advantage of the power of RAW ?
    Last edited by Ati; 16th February 2013 at 09:17 AM. Reason: spelling

  2. #2
    Administrator Manfred M's Avatar
    Join Date
    Mar 2012
    Location
    Ottawa, Canada
    Posts
    12,978
    Real Name
    Manfred Mueller

    Re: 'Pixel semolina' in image from RAW

    Your results are not surprising; high ISO, dark background, long exposure and the G11's small sensor are all significant contributing factors when it comes to image noise. Your camera, when shooting jpegs will apply noise reduction algorithms that will reduce the image noise. It will also likely result in some image smearing from the in-camera processing.

    If you want to get the best out of a RAW file, you have to post-process the image yourself to handle all of the functions that your camera takes care of for you when you shoot a jpeg; like sharpening, noise reduction, etc. If you have the right tools and know how to use them, you will be able to get a superior image out of an image like this one shooting RAW over jpeg. On the other hand, your G11 is not the best tool for shooting this type of scene.
    Last edited by Manfred M; 16th February 2013 at 12:46 PM.

  3. #3

    Join Date
    Aug 2010
    Location
    Stockholm, Sweden (and sometimes Santiago de Cuba)
    Posts
    1,089
    Real Name
    Urban Domeij

    Re: 'Pixel semolina' in image from RAW

    The ISO choice here was 1600, but your camera will certainly do better at a lower ISO setting. At long exposure times, it will apply a "dark image" to reduce noise and hot pixels, and later in post processing, the sky might be best if kept very dark, so that noise will not be noticed to a too large degree. Foliage that is moved slightly by the wind will not come out sharp, but stars will not travel far over the image area during an exposure of about minute. The angular movement is 15 per hour, or one degree per four minutes.

  4. #4
    DanK's Avatar
    Join Date
    Dec 2011
    Location
    New England
    Posts
    3,991
    Real Name
    Dan

    Re: 'Pixel semolina' in image from RAW

    Chris,

    Let me go back to basics with respects to Manfred's comment, which is exactly on target.

    You wrote: "native jpeg on left, raw on right." that is not correct. You can't view a raw file. What this should have said is: "raw processed by camera to create jpeg on left, raw processed by me to create jpeg on right." All images start as raw, and all are processed to render them into some viewable format, such as TIFF or jpeg. So, you are capturing exactly the same data in both cases. What differs is who does the processing, and what processing is done. Like Manfred, I assume that one of the differences between your two images is noise reduction applied in the camera's processing algorithm.

    The reason most of us recommend shooting raw is that the camera's pre-set processing algorithms may not match what you want, and you have considerably less room for making changes to a jpeg than to a raw file. So, to take advantage of raw, you need to study how to use postprocessing tools. I started in the wet-darkroom days, and I found learning postprocessing to be the only really difficult part of making the transition to digital. There is a LOT to learn. So, settle on a good suite of software, and start reading and practicing. For example, in this case, one of the issues (which Manfred also mentioned) is that noise reduction loses detail. so learning how best to use noise reduction--as well as how to minimize your need for it, e.g., by using low ISOs when possible--is an important skill.

    Dan

  5. #5

    Join Date
    Feb 2011
    Location
    Paris region, France
    Posts
    129
    Real Name
    Chris

    Re: 'Pixel semolina' in image from RAW

    Thanks Manfred, Urban, Dan.
    I agree a G11 pointed out of the window isn't exactly Hubble (although this evening with the Hyades, Jupiter, and the Pleiades just in front of me I could wish it was !). Urban's point is well taken, I tried 15" at ISO 200 and the angular movement is still well acceptable (sky isn't clear enough to try for the Galilean moons, where I might have had problems). Interestingly, the camera's digital zoom seems to give better results than just using the optical zoom and using PSE to crop the result.

    However, that wasn't really the point, rather, I am trying to work out what RAW can do for me that JPEG can't.
    On noise reduction, my 527pp PSE-9 manual has exactly 1 page.
    For the rest, perhaps what you're all trying to tell me is that RAW doesn't give more choices or make the impossible possible, just that it leaves the choices further downstream in the processing flow. I think I'd better stop bothering you all till I've read some more books !

    Thanks.
    Last edited by Ati; 16th February 2013 at 09:10 PM.

  6. #6
    Administrator Manfred M's Avatar
    Join Date
    Mar 2012
    Location
    Ottawa, Canada
    Posts
    12,978
    Real Name
    Manfred Mueller

    Re: 'Pixel semolina' in image from RAW

    Chris - with the right tools and knowledge on how to use them, a RAW image can give you a superior result versus an out of the camera jpeg. That being said, you may be more than happy with the jpeg output.

    I'm pretty well 100% jpeg + RAW shooter because for my use, I do spend a lot of time to try to get things right in the camera and will only work the RAW file when the jpeg is not good enough for what I want. With most of my files being destined for viewing on web pages or computer screens this works for me 90% - 95% of the time and pretty well the only time I need to go to working the RAW file is if (1) I have totally blown the shot and need the extra data to get a usable image, (2) I want to make a print and (3) when I have a shot I need to do a lot of manipulation on .

    All that being said, the main downside on the noise reduction on a camera like yours is that it tends to accomplish this by smearing the image details, so you will loose sharpness. This may be more acceptable than the alternative to you, because you have to do a lot of work to kill the colour noise in an image. If you do a bit of sharpening and convert your RAW image into B&W, you may end up with something more to your liking.

  7. #7
    DanK's Avatar
    Join Date
    Dec 2011
    Location
    New England
    Posts
    3,991
    Real Name
    Dan

    Re: 'Pixel semolina' in image from RAW

    perhaps what you're all trying to tell me is that RAW doesn't give more choices
    No, you misunderstood. Shooting raw absolutely gives you more choices. When you shoot jpeg, the picture style you select will make all the processing decisions for you--it will apply exactly the same menu, regardless of the image. When you shoot raw, you make every choice yourself, and you can individualize those for each image. Yes, you can re-edit a jepg after the fact, but with much less flexibility than a raw. That is the main point of shooting raw. But, the because shooting raw leaves the processing to you, the results will be only as good as your processing.

    However, some raw converters include the picture profiles, so you can also apply the recipe you would have applied in camera and use that as a starting point.

    I started shooting jpeg, thinking that shooting raw would be harder than it is. When I switched (regretting that I had not done so earlier), I shot raw+jpeg. However, unlike Manfred, I did that for about a month and stopped, because I found that I was never using the jpeg images.

  8. #8

    Re: 'Pixel semolina' in image from RAW

    You have a spice rack in your kitchen. Do you add exactly the same mixture of herbs and spices to every dish you cook? No. Narrow it down a little - do you add exactly the same mix to every curry you make? No. You need a different blend of spices depending on which of the many types of curry you are making.

    When you select a picture style in your camera it applies a set recipe of post processing adjustments to your images to produce a jpeg. If you select Landscape style it generally enhances greens and blues, as well as making other changes. But not every landscape is the same. What if you are shooting vistas of black volcanic rock, red Namibian sand dunes or the snow and ice of the Antarctic? Not every photo you take is the same so why would you apply the same post processing recipe. Narrow it down a bit - not every landscape you shoot is the same so why apply the same recipe?

    When dealing with a RAW file you get to decide on the mix of herbs and spices. But the key point is that you have to actually add them. If you just open a RAW file and then save it as a jpeg the chances are that it will have no, or minimal, post processing applied. For this reason it may well look worse than a jpeg. You need to use your PP software to develop the file and RAW allows you much greater flexibility when doing this.

  9. #9

    Join Date
    Feb 2011
    Location
    Paris region, France
    Posts
    129
    Real Name
    Chris

    Re: 'Pixel semolina' in image from RAW

    Thanks Dan M. There have been a couple of references to 'scene mode choices' in this thread. I never use scene mode, usually 'P', but the point on post-processing actions is taken. I'll read my 527p. Photoshop Elements manual before bothering you guys again. Even though it has only 1 page on noise reduction .

    To go back to the astronomical theme, I did finally nail Jupiter, though :



    'Pixel semolina' in image from RAW

    Thanks (and thanks to my grandson for leaving the marble on his bedspread), Chris.
    Last edited by Ati; 17th February 2013 at 10:59 AM.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •