Image noise on Photos

Discussion in 'Photography' started by seank, 23 Aug 2010.

  1. seank

    seank

    Joined:
    24 May 2007
    Posts:
    11,984
    Likes Received:
    119
    Location:
    North of Durban and South of Mozambique
    I see a lot of people post beautiful photographs on the Forum, but sometimes the "noise" on the pics tend to make the pics not so nice.

    I'll try to explain in Layman's terms what noise is as well as give some examples.

    Even though I did extract some information from the world wide web, most of the write-up is my own, and of my own experiences, not that I am a professional photographer, more so that I love to use my camera on a regular basis and learned most from trial and error.

    Definition of noise:
    Image noise is the term applied to pictures. It is almost the same as to what you hear in audio or video, but it is reflected as speckles.
    Noise is similar to grain that appears in photos taken with traditional cameras using high ISO films or similar to the "snowy" appearance of a bad TV signal.
    For example, instead of a blue sky, you notice faint pink, purple and other color speckles amongst the otherwise blue sky.


    What causes the "noise"
    Things such as exposure, temperature and different camera modes can affect image noise.
    When we use a higher ISO, we are amplifying the signal we receive from the light protons in the sky.
    No matter what you do to prevent image noise, some will always be present.Noise occurs because of electrical variations and interference in the image sensor.

    There are three primary types of noise:
    Random, fixed pattern and banding.

    Random noise revolves around an increase in intensity of the picture. It occurs through color discrepancies above and below where the intensity changes.

    Fixed pattern noise surround hot pixels. Hot pixels are pixel bits that are more intense than others surrounding it and are much brighter than random noise fluctuations. Long exposures and high temperatures cause fixed pattern noise

    Banding noise really depends on the camera as not all digital cameras will create it. During the digital processing steps, the digital camera takes the data being produced from the sensor and creates the noise from that. High ISO speeds, shadows and photo brightening will create banding noise.

    Nearly all compact digital cameras show obvious noise at ISO 400 or above. Even top-of-the-line digital SLRs are susceptible to noise, particularly at high ISO settings.

    Example of Noise

    [​IMG]

    As you can see, the higher the ISO, the more "speckles" are visible.

    But all is not lost. One can eliminate noise. There are ways to minimize noise and fortunately newer, more accurate software packages are designed to aid us in removing/reducing noise in our photos.

    How do we Prevent Noise
    One way to prevent noise is to keep our Cameras set to a low ISO, for example an ISO of 100 and lower. But.... as we all know, it is not always possible.

    If you take low light photos on a regular basis, maybe concider buying a Digital Single lens Reflex Camera, or in Short, a DSLR.
    DSLRs have large sensors and produce very little noise compared to the vast majority of compacts, which have small sensors and limited light sensitivity.

    Another way is to Use a flash to help prevent image noise if you stay within the recommended flash range for a camera. If you prefer not to use the flash, increase room lighting. Let outside light into the room through doors and windows.

    I often took photos of my tank with a white linen sheet. I'd leave all the doors and windows open, put on all the light of the tank as well as the lights in the room (Sometimes I used to bring in a DIY Fluorescent light unit- The ones you normally find in your kitchen, and mount it vertically onto a stand/wooden ladder etc).

    I would get Alida and the servant to hold the linen sheet behind me, taking off the glare on the glass, but still getting enough light into the tank to be able to "shoot" without using a flash.

    If possible, use a tripod or other support such as a table top, to keep the camera steady rather than raise the ISO.

    Let us go Back to DSLR's
    Why are DSLR images almost noise-free? The answer is simple: a larger image sensor!
    See, with a larger image sensor, each pixel can be larger and each photosite can be a bit further away from its neighbor (of course, there is an optimum distance beyond which we'll have 'gaps'). This extra distance is often enough to prevent signal leakage from one photosite onto another -- hence much less to almost no noise!

    You will find that the high ISO performance of a DSLR varies. Entry-level DSLRs are practically noise-free up to ISO 400. Better models can capture noise-free images up to ISO 1600. ISO 3200 is a stretch, even for the top line models. Turning noise reduction (NR) ON will help eliminate noise but this can happen at the expense of losing fine image detail. So far, the traditional camera manufacturers, such as Nikon and Canon, build DSLRs with better high ISO performance. Olympus, Panasonic, Pentax and Sony DSLRs seem to struggle with ISOs higher than 400. But that can change anytime.


    Summary:
    What can you do to reduce the amount of noise in your digital images?

    a.)Avoid slow or long exposures.
    b.)Avoid using high ISOs.
    c.)When comparing digital cameras, all things being equal, favor the one with the larger image sensor.
    d.)Purchase a noise reduction software. This will allow you to take pictures and not miss some great shots.

    Here you will find a perfect example of Image Noise and how to prevent it:

    Digital Camera Image Noise: Concept and Types

    Image Noise: Examples and Characteristics


    And here you can find some Imaging software programs that'll help you in fixing your photos:

    PictureCode: Product overview

    This is one of my favorite programs to use to reduce noise:

    Photoshop Elements: reduce noise in photos - Photography and video - Which? Advice
     
  2. AdS Guest




    to hide all adverts.
  3. clinton stanford

    clinton stanford

    Joined:
    11 Mar 2009
    Posts:
    2,210
    Likes Received:
    4
    Location:
    East London
    thanks Sean....some great info there;)
     
  4. MistaOrange

    MistaOrange

    Joined:
    20 Jan 2010
    Posts:
    7,756
    Likes Received:
    94
    Location:
    Somewhere in Cape Town
    Lol this is news for me as i know about pink & white noise with sound but picture noise is new for me. Thanx Sean for that great info.;-)
     
  5. seank

    seank Thread Starter

    Joined:
    24 May 2007
    Posts:
    11,984
    Likes Received:
    119
    Location:
    North of Durban and South of Mozambique
    Pleasure, hope it helps
     
  6. Broder

    Broder Mudshark

    Joined:
    13 Sep 2007
    Posts:
    2,087
    Likes Received:
    32
    Location:
    East London
    Thanks for the great info Sean. Which of the Photoshop programs would you reccommend to an amatuer photographer like me? I don't really have a specialtiy but am leaning more towards landscapes. I want something that'll be simple to use (I'm technologically challenged) and not cost the earth
     
  7. seank

    seank Thread Starter

    Joined:
    24 May 2007
    Posts:
    11,984
    Likes Received:
    119
    Location:
    North of Durban and South of Mozambique
    Mudshark, if you can get yourself Photoshop Cs4, I doubt you'll use anything else. I have worked on Elements etc, but for some reason Cs2,3,4 is just easier to work with as well as the fact that you can break up your pic in a zillion pieces, fixing basically every pixel. But like I said, this works for me and I understand the Cs 2-4 easier than the rest.

    Also, there is a lot of FREE online tutorials on these programs
     
  8. seank

    seank Thread Starter

    Joined:
    24 May 2007
    Posts:
    11,984
    Likes Received:
    119
    Location:
    North of Durban and South of Mozambique
    :lol::lol: Me too :thumbup:
     
  9. Broder

    Broder Mudshark

    Joined:
    13 Sep 2007
    Posts:
    2,087
    Likes Received:
    32
    Location:
    East London
  10. seank

    seank Thread Starter

    Joined:
    24 May 2007
    Posts:
    11,984
    Likes Received:
    119
    Location:
    North of Durban and South of Mozambique
    Nope, they older programs (And you might get them for free if you know someone who knows someone:p), But I am still happy with the older versions, as the newer versions have extra stuff on that I never use
     
  11. Broder

    Broder Mudshark

    Joined:
    13 Sep 2007
    Posts:
    2,087
    Likes Received:
    32
    Location:
    East London
  12. Nemos Janitor

    Nemos Janitor

    Joined:
    7 Feb 2009
    Posts:
    8,384
    Likes Received:
    286
    Location:
    Joe's Mountain
    Thanks Sean. Great job, a lot of effort went into that and will make a difference. LEAD SA bud.
     
  13. seank

    seank Thread Starter

    Joined:
    24 May 2007
    Posts:
    11,984
    Likes Received:
    119
    Location:
    North of Durban and South of Mozambique
    Pleasure guys
     
  14. seank

    seank Thread Starter

    Joined:
    24 May 2007
    Posts:
    11,984
    Likes Received:
    119
    Location:
    North of Durban and South of Mozambique
    @ Broder, dunno, just heard the guys talking some time ago that they downloadedCS3 for free, full package
     
  15. Reef Maniac

    Reef Maniac MASA Contributor

    Joined:
    15 May 2007
    Posts:
    2,899
    Likes Received:
    112
    Location:
    Bloemfontein
    Good one, Sean :thumbup:

    Yes, unfortunately the license expires after a while (1 month, I think...) I agree with Sean, though - CS4 is more than adequate... Of course, one can also use Adobe Lightroom, at about 25% of the cost of CS5, but I don't really like it... suppose I'm old fasioned in that I want to keep the photos in separate folders of my choice, and not in a big database...

    Hennie
     
  16. herkie

    herkie R.I.P.

    Joined:
    18 May 2007
    Posts:
    884
    Likes Received:
    3
    Location:
    The Bay of KZN
    Thanks SK this has obviously taken a lot of time to research and compile. Now I have to look see if I know 'Someone'.
     
  17. Nemos Janitor

    Nemos Janitor

    Joined:
    7 Feb 2009
    Posts:
    8,384
    Likes Received:
    286
    Location:
    Joe's Mountain
    Hennie not sure what you mean buy keeping photos in seperate folders? After each shoot i download my card (RAW) or (jay-peg) depending which camera i am using, to an external drive for backup and then import to Light room as say "diving pic's" -- "sodwana" --"7 mile reef" --"nov 2009". One can then delete the garbage and process the rest. Processed pic's can then be filled in any folder in a few formats.

    Never used CS3 - 5 so i do do not understand why you say CS5 is better in this regard. Also my LR experience is also very new so no I'm no expert in a comparison.
     
  18. Nemos Janitor

    Nemos Janitor

    Joined:
    7 Feb 2009
    Posts:
    8,384
    Likes Received:
    286
    Location:
    Joe's Mountain
    Sean and Hennie, To do good photo editing, and to see Noise, grain, sharpen, etc. What screen dose one need. I Have a few screens and each pic looks different on each one.

    Is there a seperate program/software or pc screen set up procedure that is needed.
     
  19. seank

    seank Thread Starter

    Joined:
    24 May 2007
    Posts:
    11,984
    Likes Received:
    119
    Location:
    North of Durban and South of Mozambique
    Nemo, if you want to do it right, you have to calibrate your screen. I used a friends calibration machine some months ago.

    Problem is, not all the people sees blue, green, red light the same, best is to calibrate

    I have a 23 inch HD LCD Monitor
     
  20. herkie

    herkie R.I.P.

    Joined:
    18 May 2007
    Posts:
    884
    Likes Received:
    3
    Location:
    The Bay of KZN
    Not seeing colours the same is so true, blue and green seems to be a major colour argument in my house.
     
  21. Reef Maniac

    Reef Maniac MASA Contributor

    Joined:
    15 May 2007
    Posts:
    2,899
    Likes Received:
    112
    Location:
    Bloemfontein
    Agreed. I bought myself a Spyder 3 screen calibrator some months ago, and it made a huge difference in how the photos look on-screen vs how they look when printed. Apart from needing to correct the colours, most screens are also set too bright, and this results in the printed photos being too dark as well as not having the correct colours. The calibrator sorted out both the colours and the brightness for me. I can bring mine with me the next time I visit JHB, and will gladly calibrate your monitor for you - let me know if you are interested.

    As I said, I'm not an expert with Lightroom, but from the little bit that I played with it I gathered that it only "imports" some data about each photo into it's database. Whatever changes you make to the photo is only recorded in the database as well, and one thus needs to save a "sidecar" file WITH the actual image if you want the changes to be visible once the image is opened in another viewer/editor program. Obviously, once a photo has been converted and saved in (say) jpeg format, the image will remain changed, but if one opens the (edited) RAW file in (say) Canon DPP or even in Photoshop without the additional sidecar file, the image loses all it's editing. I just prefer to load the physical image into a sub-folder of my choice with Adobe Bridge, and then to edit the RAW image using Camera Raw (part of the CS3/4/5 "suite" of programs). As I said earlier, I'm probably just old-fashioned with this... Lightroom apparently works great for most people :whistling:

    Hennie
     
    Last edited: 25 Aug 2010
Recent Posts

Loading...
Similar Threads - Image noise Photos Forum Date
Local image hosting site General Discussions and Advice 28 Jan 2015
Awesome shrimp image Fish Pics 22 Jan 2014
Image hosting site General Discussions and Advice 25 Nov 2013
New Image Uploader Trial Forum Suggestions and Feedback 28 May 2013
Image uploader? Forum Usage 25 Oct 2012
Who moved the "image uploader" link? Forum Suggestions and Feedback 23 Oct 2012
Image Hosting changes Forum Suggestions and Feedback 15 Jul 2012