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Thread: noob question abt CCD size and noise

  1. #1

    Default noob question abt CCD size and noise

    Hi to all the experts here, i'm interested in buying a new 18x zoom panasonic prosumer cam. the cam comes with 8 megapixel and 1/2.5" CCD sensor size. i have read that with 8megapizel, 1/2.5" sensor size is too small, which will cause image to be noisy.

    my question is, if i want a clear and sharp noiseless pic, other than manually set (or force) the ISO at 100, will it help if i take pictures at lower picture size? that is to say instead of taking pic at full 8mega pizxel, i take the picture at probably 1024x960 size only.

    Thanks for viewing..

  2. #2

    Default Re: noob question abt CCD size and noise

    hmm...
    40 view and no reply?


    if only some one could answer my question...

  3. #3

    Default Re: noob question abt CCD size and noise

    Read from somewhere that it does helps a little to lower down the Megapixel to reduce noise. But I don't think is going to help much. Try before a few times.

    In theory is should reduce. But each CCD and Camera CPU handle the task differently. So It really hard to tell if this helps. But then it not making any sense to get an 8MP camera and lower all the time to 5MP for photo taking. But I do know 5MP is more then enough for any print up to A4. It depends on you

    - How much noisy you willing to accept.
    - Size you printing I believe small print wouldn't show noise badly.

  4. #4
    Senior Member zac08's Avatar
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    Default Re: noob question abt CCD size and noise

    Quote Originally Posted by zzyzx View Post
    Hi to all the experts here, i'm interested in buying a new 18x zoom panasonic prosumer cam. the cam comes with 8 megapixel and 1/2.5" CCD sensor size. i have read that with 8megapizel, 1/2.5" sensor size is too small, which will cause image to be noisy.

    my question is, if i want a clear and sharp noiseless pic, other than manually set (or force) the ISO at 100, will it help if i take pictures at lower picture size? that is to say instead of taking pic at full 8mega pizxel, i take the picture at probably 1024x960 size only.

    Thanks for viewing..
    Well, essentially, what you've read is correct only if you intend to blow up the picture to a large size. Normally such camera's are limited to a certain amount of ISO values like up to 400 to limit such noise problems.

    Reducing the picture quality? Tat I'm not very sure, but with a smaller file, you're unable to blow up the picture too much and may limit the problem slightly but give you other problems.

    Do look for a good noise reduction software on the market and you can shoot all you like.
    Michael Lim
    My Flickr Site

  5. #5

    Default Re: noob question abt CCD size and noise

    thanks for the replies,

    i'm very interested in the panny fz18 and very likely to get it when it's released. only thing is dunno much abt it's IQ yet.

    btw wat is the long barrel thing called in the pic?


  6. #6
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    Default Re: noob question abt CCD size and noise

    Apart from sensor size, the camera's processor (Like Digic, Venus, Expeed) plays a part to reduce the noise, so it depends on the manufacturer's algo and settings too.

    The additional "long barrel" is a telephoto adaptor. It basically adds a multiplying factor (say, 1.4, or 1.7) to the focal length (zoom). There are some wide angle adaptors too, to give the camera a wider coverage (say, 0.7, or 0.8).

  7. #7

    Default Re: noob question abt CCD size and noise

    Quote Originally Posted by zzyzx View Post
    Hi to all the experts here, i'm interested in buying a new 18x zoom panasonic prosumer cam. the cam comes with 8 megapixel and 1/2.5" CCD sensor size. i have read that with 8megapizel, 1/2.5" sensor size is too small, which will cause image to be noisy.

    my question is, if i want a clear and sharp noiseless pic, other than manually set (or force) the ISO at 100, will it help if i take pictures at lower picture size? that is to say instead of taking pic at full 8mega pizxel, i take the picture at probably 1024x960 size only.

    Thanks for viewing..
    The amount of Noise is inversely proportional not to sensor size per se but proportionally to pixel density (i.e. how closely packed the photosites are physically within the CCD sensor) and individual photosite size (which determines how much light signal is collected per photosite. The more light is collected, the lower the noise to light signal ratio which determines how apparent the noise will be.).

    In most situations, all the photosites (i.e. 8 MP in this case) are still used even if you choose a lower picture resolution (this is evident in that the 35mm equivalent focal length remains the same regardless of the picture resolution you choose. In some cameras, only a part of the CCD sensor is used and therefore the angle of view is narrower, resulting in higher 35mm equivalent focal length for those lower resolution pictures even though the actual focal length remains the same). (This part requires some understanding of angle of view, focal length vs sensor size).

    In the usual Bayer Array arrangement, each pixel in the picture resolution does not correspond exactly to one photosite but is a calculated value using the values collected by a number of adjacent photosites (each of them collecting only a value for Red, Green or Blue).

    So at the raw level, you're going to get the same amount of noise regardless of the picture resolution chosen.

    A lower resolution picture is usually just a downsizing of resolution from original picture in a way similar to what downsizing does in post-processing software (such as in photoshop).

    At lower resolution, noise will be less apparent to the eyes. However, it also means that at high ISO where there is a high level of noise at the raw level, there is going to be a much more severe loss of details in lower resolution pictures.

    In the case of the FZ18, I don't know how the camera handles the downsizing and jpeg compression in its algorithm. Only someone with the camera can try out and show us the result. Theoretically, since noise will definitely be high at the raw level due to a high pixel density and small photosites on the small 1/2.5" CCD sensor, you still cannot run away from the effects of high noise at high ISO at the raw level even if a low resolution is chosen and it is basically still the same trade off between noise and details at various picture resolution.
    Last edited by Clockunder; 25th August 2007 at 11:45 AM.

  8. #8

    Default Re: noob question abt CCD size and noise

    wow i learnt a lot here...

    looks like i'll got to wait till the fz18 is out in store then comapre it with fz50... hopefully the fz18 doesn't disappoint me...

  9. #9
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    Default Re: noob question abt CCD size and noise

    My opinion is if you are concerned about noise, maybe you can try cameras with lower zoom factors. At 18x for the FZ18, you are going need considerable high shutter speed if you want sharp pictures even with image-stabilizing on. This may translate into needing to shoot at higher ISO to get that shutter speed (though the FZ18 aperature is quite large even at tele). Higher ISo = more noise again.

  10. #10
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    Default Re: noob question abt CCD size and noise

    I think probably at lower resolution, the noise will appear to be less not because it is not there, but rather it is smaller. When you take a high resolution picture and view it on the monitor, you may find that there is more noise because all the noise are blown up to a visible level.

  11. #11

    Default Re: noob question abt CCD size and noise

    i think still can get long zoom.
    It's not as if you zoom in everytime.
    And if the brightness of the envt is ok, then no problem to get a better shutter speed.
    Or at most you change aperture size or -EV when u zoom in.
    iso is the last thing to change when still in the same environmental settings.

    Maybe u can also get a tripod for long zoom purpose.
    For eg u climbed a hill and u spotted a very small hut at the opposite hill.
    This is the time u wished u had a tele lens.
    Need to change iso? no need.
    Place on tripod will do.
    If no tripod, then use your creativity to change settings or improvise support.
    Last edited by sin77; 26th August 2007 at 10:10 AM.
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