resolution/compression questions from a newbie

Discussion in 'Digital Photography' started by TW, Jun 11, 2005.

  1. TW

    TW Guest

    Hi,

    I have just purchased my first digital camera: a Olympus D-540 Zoom.
    Having
    read through the (rather louzy) user's manual and a couple of books
    from the
    local library on digital photography, I am still left with two very
    basic
    questions:

    1) RESOLUTION SELECTION:

    My camera offers the following resolutions:

    * 640x480 (also identified as SQ2)
    * 1600x1200 (also identified as SQ1)
    * 2048x1536 (also identified as HQ)
    * 2048x1536 (also identified as SHQ)

    The camera has 3.2 effective megapixels

    I think I understand that the difference between the HQ and SHQ modes
    is the
    degree of jpeg compression. However, what the manual does not say is
    how
    important this compression is. My first question is:

    Can I use 2048x1536/HQ for 8x10 prints or must I use 2048x1536/SHQ?
    What is
    *exactly* the difference between the HQ and SHQ modes?

    2) JPEG LOSSY COMPRESSION:

    I understand that each time a jpeg picture is saved it looses quality
    due to the repeated compression. My second question is:

    Does this also apply to pictures viewed on the camera's LCD? Does the
    camera's
    software save the pic each time it is shown on the LCD, or does it
    simply
    display it on demand and discard the displayed picture each time
    without
    touching the saved one (which would make more sense to me).

    Many thanks in advace for your pointers!
    TW, Jun 11, 2005
    #1
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  2. TW

    Sheldon Guest

    "TW" <> wrote in message
    news:...
    > Hi,
    >
    > I have just purchased my first digital camera: a Olympus D-540 Zoom.
    > Having
    > read through the (rather louzy) user's manual and a couple of books
    > from the
    > local library on digital photography, I am still left with two very
    > basic
    > questions:
    >
    > 1) RESOLUTION SELECTION:
    >
    > My camera offers the following resolutions:
    >
    > * 640x480 (also identified as SQ2)
    > * 1600x1200 (also identified as SQ1)
    > * 2048x1536 (also identified as HQ)
    > * 2048x1536 (also identified as SHQ)
    >
    > The camera has 3.2 effective megapixels
    >
    > I think I understand that the difference between the HQ and SHQ modes
    > is the
    > degree of jpeg compression. However, what the manual does not say is
    > how
    > important this compression is. My first question is:
    >
    > Can I use 2048x1536/HQ for 8x10 prints or must I use 2048x1536/SHQ?
    > What is
    > *exactly* the difference between the HQ and SHQ modes?


    It's a compromise to get more images on a memory card. The less compression
    will give you the best image. The question is can you tell the difference.
    I suggest you try taking two identical photos using both modes, blow them
    both up to 8x10 and see if you can tell the difference.
    >
    > 2) JPEG LOSSY COMPRESSION:
    >
    > I understand that each time a jpeg picture is saved it looses quality
    > due to the repeated compression. My second question is:
    >
    > Does this also apply to pictures viewed on the camera's LCD? Does the
    > camera's
    > software save the pic each time it is shown on the LCD, or does it
    > simply
    > display it on demand and discard the displayed picture each time
    > without
    > touching the saved one (which would make more sense to me).
    >
    > Many thanks in advace for your pointers!


    Not sure what you mean here. Are you talking about the image you see before
    you take the shot, or the image you see when you review what you've just
    taken? The image you see before you take the shot will be the same
    regardless of what mode you use, and I don't think you will see much
    difference in any mode on that small LCD after the shot is taken. The image
    is saved to your memory card. The LCD is just a way to preview and review
    the image.
    Sheldon, Jun 11, 2005
    #2
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  3. TW

    Stacey Guest

    TW wrote:

    > My first question is:
    >
    > Can I use 2048x1536/HQ for 8x10 prints or must I use 2048x1536/SHQ?
    > What is
    > *exactly* the difference between the HQ and SHQ modes?


    You'll need to go shoot some images at both settings and see for yourself.
    If you're wanting to make 8X10 prints from a 3.2MP camera, I'd be using SHQ
    mode exclusively. I'm sure on some subjects you wouldn't see any difference
    but others it would show up. You won't know until it's too late. CF cards
    are cheap and this camera's files even in SHQ mode aren't that large. If
    you were only making 4X6 prints, HQ would probably be just fine.


    >
    > 2) JPEG LOSSY COMPRESSION:
    >
    > I understand that each time a jpeg picture is saved it looses quality
    > due to the repeated compression. My second question is:
    >
    > Does this also apply to pictures viewed on the camera's LCD?


    Not at all. What they are talking about is if you open the jpeg in something
    like photo shop, do some deiting and then resave it as a jpeg. Then open
    again, edit some more and resave as a jpeg. That's the sort of thing you
    don't want to do.
    --

    Stacey
    Stacey, Jun 11, 2005
    #3
  4. TW

    TW Guest

    Stacey wrote:

    > You'll need to go shoot some images at both settings and see for yourself.
    > If you're wanting to make 8X10 prints from a 3.2MP camera, I'd be using SHQ
    > mode exclusively. I'm sure on some subjects you wouldn't see any difference
    > but others it would show up. You won't know until it's too late. CF cards
    > are cheap and this camera's files even in SHQ mode aren't that large. If
    > you were only making 4X6 prints, HQ would probably be just fine.


    The problem is that the file size difference between SHQ and HQ is
    really huge. I bought a 128MB card which can hold either about 325 HQs
    or 110 SHQs (not exact figures - I have a couple of pictures already on
    it). Nor can I afford a bigger card. Do you think 5x7 prints will look
    ok with HQ?

    > Not at all. What they are talking about is if you open the jpeg in something
    > like photo shop, do some deiting and then resave it as a jpeg. Then open
    > again, edit some more and resave as a jpeg. That's the sort of thing you
    > don't want to do.


    That's what I thought but I wanted to check anyway. (although the
    program I use - the GIMP 2.0 - allows me to manually set a compression
    of my jpegs. I can save without any compression if I want).

    Many thanks!

    TW
    TW, Jun 11, 2005
    #4
  5. TW

    Ken Weitzel Guest

    TW wrote:

    <snip>


    > The problem is that the file size difference between SHQ and HQ is
    > really huge. I bought a 128MB card which can hold either about 325 HQs
    > or 110 SHQs (not exact figures - I have a couple of pictures already on
    > it). Nor can I afford a bigger card. Do you think 5x7 prints will look
    > ok with HQ?


    Hi TW...

    Just on the off chance that you haven't yet realized it,
    you can change qualities mid-stream...

    Ken
    Ken Weitzel, Jun 11, 2005
    #5
  6. TW

    Stacey Guest

    TW wrote:

    > Stacey wrote:
    >
    >> You'll need to go shoot some images at both settings and see for
    >> yourself. If you're wanting to make 8X10 prints from a 3.2MP camera, I'd
    >> be using SHQ mode exclusively. I'm sure on some subjects you wouldn't see
    >> any difference but others it would show up. You won't know until it's too
    >> late. CF cards are cheap and this camera's files even in SHQ mode aren't
    >> that large. If you were only making 4X6 prints, HQ would probably be just
    >> fine.

    >
    > The problem is that the file size difference between SHQ and HQ is
    > really huge. I bought a 128MB card which can hold either about 325 HQs
    > or 110 SHQs (not exact figures - I have a couple of pictures already on
    > it). Nor can I afford a bigger card. Do you think 5x7 prints will look
    > ok with HQ?



    You have to decide this for yourself. Like I said shoot a scene with some
    detail in it at both settings and make a couple of prints. The other
    question is how often are you going to need to shoot over 110 images at a
    time? That's like 3 rolls of 36 exposures! Also 128MB cards can be had
    really cheap these days.. Easily can be had for $20 shipped.

    http://tinyurl.com/9vbd4

    http://tinyurl.com/8d9br
    --

    Stacey
    Stacey, Jun 12, 2005
    #6
  7. On 11 Jun 2005 05:28:05 -0700, "TW" <> wrote:

    >My camera offers the following resolutions:
    >
    >* 640x480 (also identified as SQ2)
    >* 1600x1200 (also identified as SQ1)
    >* 2048x1536 (also identified as HQ)
    >* 2048x1536 (also identified as SHQ)
    >
    >The camera has 3.2 effective megapixels
    >
    >I think I understand that the difference between the HQ and SHQ modes
    >is the
    >degree of jpeg compression. However, what the manual does not say is
    >how
    >important this compression is.


    If you must conserve space, the first you do is to go to a higher
    compression level (HQ) - before sacrificing resolution (SQ1).

    >Can I use 2048x1536/HQ for 8x10 prints or must I use 2048x1536/SHQ?
    >What is *exactly* the difference between the HQ and SHQ modes?


    Only the compression level applied for the save JPEGs - a lower
    compression level equals higher picture quality. If you can, use
    the SHQ always - you will /not/ know beforehand when you need the
    better picture quality!

    And do backup to other loctions (using cd/dvd) on a regular basis.

    >2) JPEG LOSSY COMPRESSION:
    >
    >I understand that each time a jpeg picture is saved it looses quality
    >due to the repeated compression. My second question is:
    >
    >Does this also apply to pictures viewed on the camera's LCD? Does the
    >camera's
    >software save the pic each time it is shown on the LCD, or does it
    >simply
    >display it on demand and discard the displayed picture each time
    >without
    >touching the saved one (which would make more sense to me).


    Displaying the pictures, or even opening them in a picture editing
    software and closing it, will do nothing to them.

    Just make sure when you edit (correcting redeye, crop, etc) your
    pictures that you don't save the edited picture using the same name:

    i.e. img0532.jpg should be /saved as/ (something like)

    img0532_edited.jpg or img0532_crop.jpg
    Rolf Egil Sølvik, Jun 12, 2005
    #7
  8. TW

    TW Guest

    First - thanks to all for your pointers!

    Second - I mistakenly identified my memory card as 128MB. It is in
    fact 256MB. And yes, Stacy, that us usually plenty enough. But the
    problem is that I will be going to a 3 week trip throught the USA and
    Canada this summer and I am not at all sure where I will be able to
    find a computer with a CD burner and a USB port (software wise I will
    take a GNU/Linux live-CD with everything on it which I can use on any
    computer, including any Windows machine, without even touching the hard
    drives. Just boot-off my live-CD and a complete operating system with
    a very good CD-burning application loads itself into memory). I will
    try libraries, but many of them do not have computers with USB ports or
    CD-burners (and their staff tends to freak out when "strange" software
    is run on them).

    Of course, I could take a laptop - but that is kind of a pain for a
    camping/outdoors -oriented trip.

    Anyway - thanks for all the advise and let me know if you have any
    ideas where I could transfer my pics from my card to a CD!

    Kind regards,

    TW
    TW, Jun 12, 2005
    #8
  9. "TW" <> wrote:
    >
    > Anyway - thanks for all the advise and let me know if you have any
    > ideas where I could transfer my pics from my card to a CD!


    There are several products about the size of a paperback book that allow you
    to download and store images from your cards on an internal hard drive. I
    have the Epson P-2000, but it's a tad pricey; I understand there are more
    cost-effective products out there. The Epson is nice because the screen is
    great, so you can show people images with it.

    David J. Littleboy
    Tokyo, Japan
    David J. Littleboy, Jun 12, 2005
    #9
  10. TW

    Stacey Guest

    TW wrote:


    >
    > Anyway - thanks for all the advise and let me know if you have any
    > ideas where I could transfer my pics from my card to a CD!
    >



    Don't most of those kiosk based system offer a CD burning option? Might be a
    simple solution if this isn't an often faced problem. You'll be pissed it
    you get that "once in a lifetime" shot and it's HQ instead of SHQ. Then
    again can't you mix these on the same card? You should be able to see in
    the finder if the image looks promising.

    --

    Stacey
    Stacey, Jun 12, 2005
    #10
  11. TW wrote:
    > First - thanks to all for your pointers!
    >
    > Second - I mistakenly identified my memory card as 128MB. It is in
    > fact 256MB. And yes, Stacy, that us usually plenty enough. But the
    > problem is that I will be going to a 3 week trip throught the USA and
    > Canada this summer and I am not at all sure where I will be able to
    > find a computer with a CD burner and a USB port (software wise I will
    > take a GNU/Linux live-CD with everything on it which I can use on any
    > computer, including any Windows machine, without even touching the hard
    > drives.


    Do yourself a favor: buy a couple of additional CF cards. I personally
    prefer 1 Gig cards now, but I shoot sports, and that's usually about
    right for one game.

    You should be able to find some Gig or half gig cards fairly cheaply.
    And in the quiet of the evening it's reasonable to delete the duplicates
    and clunkers.

    Bon voyage!

    --
    John McWilliams
    John McWilliams, Jun 21, 2005
    #11
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