Results 1 to 7 of 7

Thread: Noise and aperture prob of digicam

  1. #1

    Default Noise and aperture prob of digicam

    Hi have some questions hope u guys can enlighten me..

    My c730 has noise problems, i read that it is due to the ccd being too small for the large megapixels. So my question is DSLR with resolution as large as 6.3 MP will have such problems not? Or do they use somthing else. Canons CMOS sensor is a ccd not?

    Also I read abt a digicam will have aperture that is not true to the value displayed. Likfe f2.8 on digicam is actualy f11 on a SLR. Why is this so?
    For DSLR is this also the case?

  2. #2

    Default

    Quote Originally Posted by wetdesert
    Canons CMOS sensor is a ccd not?
    from semiconductor point of view:

    CCD is CCD
    CMOS is CMOS
    CCD can't be CMOS
    CMOS can't be CCD
    Both CCD and CMOS can be used as photodetector.

  3. #3

    Default

    Quote Originally Posted by wetdesert
    Also I read abt a digicam will have aperture that is not true to the value displayed. Likfe f2.8 on digicam is actualy f11 on a SLR. Why is this so?
    For DSLR is this also the case?
    Aperture size will depend on the lens design and size. It's not related to the size of the photodetector / photosensor.

  4. #4
    Member
    Join Date
    May 2003
    Location
    Singapore
    Posts
    334

    Default

    Quote Originally Posted by wetdesert
    My c730 has noise problems, i read that it is due to the ccd being too small for the large megapixels. So my question is DSLR with resolution as large as 6.3 MP will have such problems not? Or do they use somthing else.
    Digital SLRs have less noise than consumer digicams because the individual pixel sizes are larger. Read this ... Making sense of sensor sizes

    Also I read abt a digicam will have aperture that is not true to the value displayed. Likfe f2.8 on digicam is actualy f11 on a SLR. Why is this so?
    For DSLR is this also the case?
    The aperture value is true. I think what you are referring to is the depth of field which is related to the real focal length. Not the so called "35mm equivalent" which is often quoted. Take a look at the true focal length which is written on the front of your camera lens. You will be surprise how "wide angle" it is. The longer the true focal length, the shallower the depth of field if the subject distance and aperture are constant.

  5. #5
    Member
    Join Date
    Jan 2002
    Location
    Western SG
    Posts
    1,537

    Default

    Sometimes it's not just the number of pixels. The size of the sensor plays a part to the noise level too.

    A article in photo.net : "Size Matters"

  6. #6
    Member
    Join Date
    Jan 2002
    Location
    AMK, Singapore
    Posts
    527

    Default

    Quote Originally Posted by Snowcrash
    A article in photo.net : "Size Matters"
    Hmm.. interesting article.

    The MTF stuff is new to me though.. So for a particular sensor size, shooting at bigger aperture (eg.. f2, f4) would potentially result in better quality than shooting at smaller aperture (eg.. f8, f11).. assuming all else being equal..

  7. #7

    Default

    That's the reason why digicams are limited to f8 usually.

Bookmarks

Posting Permissions

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