How many megapixels do I need?

Discussion in 'Digital Photography' started by Doug, Aug 16, 2004.

  1. Doug

    Doug Guest

    Hello, this is my 1st post in this group. I have been a hobby
    photographer for 20 years or so, and have always used my trusty Pentax
    MX. Now I want to convert to digital but after shopping around for a
    while I am confused. I noticed that if you want to submit a photo to
    Popular Photo and Imaging's best shots contest, you have to submit a
    minimum 3 MB jpeg file. I am asuming that that also means to get a
    decent print for whatever reason that that would be the minimum file
    size depending on compression factor and a lot of other variables. At
    that time I thought that a 3 megapixel camera would give roughly that
    big of a file, now I found out you would need closer to a 6 megapixel
    camera. Big difference in price especially for good quality camera.
    Anyway what you recommend for me to get into the digital world? I know
    that budget is the big factor i am limited to $500 canadian or about
    $400 US. The cameras I have seen that I like the style and seem to
    have good lenses are: Canon A80; Kodak DX6490; DX7440; DX7630; and
    Panasonic DMC-LC70, all 4 to 6 MPixels...
    Cheers
    Doug
    Doug, Aug 16, 2004
    #1
    1. Advertising

  2. Doug

    Frank ess Guest

    Doug wrote:
    > Hello, this is my 1st post in this group. I have been a hobby
    > photographer for 20 years or so, and have always used my trusty Pentax
    > MX. Now I want to convert to digital but after shopping around for a
    > while I am confused. I noticed that if you want to submit a photo to
    > Popular Photo and Imaging's best shots contest, you have to submit a
    > minimum 3 MB jpeg file.


    I'll be interested in seeing how this plays out. I have a recent "8 MP"
    camera that gives two to two-and-a-half MB files in its 8MP-FINE mode.
    Messed with and saved in PSD, files are in the 14 MB range.

    RAW (nef) files are 12+ MB (and won't yet open in PS CS...).

    Is there some magic threshold at 3MB for jpegs?


    Frank ess
    Frank ess, Aug 16, 2004
    #2
    1. Advertising

  3. Doug

    Roger Guest

    Doug,

    You may also want to check the archives on this topic as there has
    been a ton of material written about this subject.

    You haven't said how big of a picture you intend to produce. I'm going
    to assume that you are interested in some sort of prints. Printing
    digital files at 300 ppi is a rule of thumb for "photo quality"
    prints. Many of the commercial systems use this measure.

    If you take a 4x3 digital image proportion and use the 300 ppi you get
    something like 2.4 MP to get a 4x6 print (assumes some cropping to get
    the elongated 4x6 print). So you can do the similar math for other
    print sizes. An 8x10 print at 300 ppi would be something like 7.68 MP.
    However there are a lot of arguable points in this "mapping". One is
    that you don't need 300ppi, something less like 240ppi will work.
    Another point is that some gain can be had by resizing images in the
    last step, using interpolating modes to "manufacture" pixels in the
    print step. There are many ways to do this, and some special enhancing
    tools are available and the quality of interpolating methods is also
    an interesting study although those that come in PhotoShop Elements 2
    and Paint Shop Pro 8.0 are good enough if you aren't trying for more
    than a factor of 50%.

    So it's not all hard math, but there are some starting points. I find
    that my 5 MP Canon s60 produces files that look great (with post
    processing care) up to 11x14. Some subject detail "up-sizes" better
    than others. So YMMV depending on tastes and final effect. I'm pretty
    happy with 5MP. Prior to purchasing the s60, my wife did all our
    digital photography (with the exception of those film images that I
    scanned) and we learned to do a lot of photo sharing (email and web,
    4x6's and occasional 8x10s) with just 2 MP.

    I have a friend who is making great pictures with 4MP Nikon D2H. So
    you can argue that a pixel is not a pixel, or some other abstract
    stuff. What you are looking for in a final result will have a lot to
    do with the number of pixels you think are needed. As your post
    processing skills develop you may want to determine more how much time
    you have to spend on such activities and this will also eventually
    weigh into the equation, but probably not on the first camera.

    I personally think you should be able to do a lot of great photography
    with a 4MP Canon A80 and they have a very attractive price point right
    now. Probably soon to be replaced.

    It's good to try to understand this, but it's not as cast-in-concrete
    as it may seem. My recommendation is to buy one that's "good-enough"
    to meet 90% of your needs and stays within your budget, learn what the
    processing and storage of images is all about and then go from there.

    Regards,
    Roger

    On 16 Aug 2004 12:44:18 -0700, (Doug) wrote:

    >Hello, this is my 1st post in this group. I have been a hobby
    >photographer for 20 years or so, and have always used my trusty Pentax
    >MX. Now I want to convert to digital but after shopping around for a
    >while I am confused. I noticed that if you want to submit a photo to
    >Popular Photo and Imaging's best shots contest, you have to submit a
    >minimum 3 MB jpeg file. I am asuming that that also means to get a
    >decent print for whatever reason that that would be the minimum file
    >size depending on compression factor and a lot of other variables. At
    >that time I thought that a 3 megapixel camera would give roughly that
    >big of a file, now I found out you would need closer to a 6 megapixel
    >camera. Big difference in price especially for good quality camera.
    >Anyway what you recommend for me to get into the digital world? I know
    >that budget is the big factor i am limited to $500 canadian or about
    >$400 US. The cameras I have seen that I like the style and seem to
    >have good lenses are: Canon A80; Kodak DX6490; DX7440; DX7630; and
    >Panasonic DMC-LC70, all 4 to 6 MPixels...
    >Cheers
    >Doug
    Roger, Aug 16, 2004
    #3
  4. Doug

    Roger Guest

    On Mon, 16 Aug 2004 15:37:23 -0500, Roger <> wrote:

    >Doug,
    >
    >You may also want to check the archives on this topic as there has
    >been a ton of material written about this subject.
    >
    >You haven't said how big of a picture you intend to produce. I'm going
    >to assume that you are interested in some sort of prints. Printing
    >digital files at 300 ppi is a rule of thumb for "photo quality"
    >prints. Many of the commercial systems use this measure.
    >

    ... snip ...
    >I personally think you should be able to do a lot of great photography
    >with a 4MP Canon A80 and they have a very attractive price point right
    >now. Probably soon to be replaced.
    >
    >It's good to try to understand this, but it's not as cast-in-concrete
    >as it may seem. My recommendation is to buy one that's "good-enough"
    >to meet 90% of your needs and stays within your budget, learn what the
    >processing and storage of images is all about and then go from there.
    >
    >Regards,
    >Roger


    Doug,

    After posting this, I started thinking more about this 3MP jpg
    requirement. I have to admit that I think there are so many variables
    that I don't have a clue what the magazine editors want or why they
    want a 3MP jpg. I think I've completely missed you point. I know how
    to "contrive" a 3 MP file using some of the variables you suggested,
    but I don't know what 3 MP means as a "standard" for submittal.

    Sorry if I've added to the confusion, but I am confused by the
    requirement.

    Regards,
    Roger
    Roger, Aug 16, 2004
    #4
  5. (Doug) wrote in news:3eea723b.0408161144.5e84c648
    @posting.google.com:

    > Hello, this is my 1st post in this group. I have been a hobby
    > photographer for 20 years or so, and have always used my trusty Pentax
    > MX. Now I want to convert to digital but after shopping around for a
    > while I am confused. I noticed that if you want to submit a photo to
    > Popular Photo and Imaging's best shots contest, you have to submit a
    > minimum 3 MB jpeg file.


    According to this page it is 3 MP JPEG.

    http://www.popphoto.com/article.asp?section_id=4&article_id=893

    > I am asuming that that also means to get a
    > decent print for whatever reason that that would be the minimum file
    > size depending on compression factor and a lot of other variables. At
    > that time I thought that a 3 megapixel camera would give roughly that
    > big of a file, now I found out you would need closer to a 6 megapixel
    > camera. Big difference in price especially for good quality camera.
    > Anyway what you recommend for me to get into the digital world? I know
    > that budget is the big factor i am limited to $500 canadian or about
    > $400 US. The cameras I have seen that I like the style and seem to
    > have good lenses are: Canon A80; Kodak DX6490; DX7440; DX7630; and
    > Panasonic DMC-LC70, all 4 to 6 MPixels...


    Now - your trusty MX is a very nice SLR camera (got one to although
    the exposure meter is broken) with a very nice SLR viewfinder. You
    also can put some nice lenses on that camera.

    If you want something similar you want a DSLR. Then we are talking
    about $1000 and not $400. And if we are talking about a Pentax
    DSLR, we are talking about $1300 or so.


    /Roland
    Roland Karlsson, Aug 16, 2004
    #5
  6. In article <Xns9547ECC14AE05klotjohan@130.133.1.4>,
    says...
    > If you want something similar you want a DSLR. Then we are talking
    > about $1000 and not $400. And if we are talking about a Pentax
    > DSLR, we are talking about $1300 or so.
    >
    >
    > /Roland


    Unless he can wait a few months for Pentax's announced "budget" dSLR for
    around $900.
    --
    http://www.pbase.com/bcbaird/
    Brian C. Baird, Aug 16, 2004
    #6
  7. Brian C. Baird <> wrote in news:MPG.1b8af356948ba28b98a019
    @news.verizon.net:

    > Unless he can wait a few months for Pentax's announced "budget" dSLR for
    > around $900.


    Thats what I am doing :)


    /Roland
    Roland Karlsson, Aug 16, 2004
    #7
  8. Doug

    jpc Guest

    On 16 Aug 2004 12:44:18 -0700, (Doug) wrote:

    >Hello, this is my 1st post in this group. I have been a hobby
    >photographer for 20 years or so, and have always used my trusty Pentax
    >MX. Now I want to convert to digital but after shopping around for a
    >while I am confused. I noticed that if you want to submit a photo to
    >Popular Photo and Imaging's best shots contest, you have to submit a
    >minimum 3 MB jpeg file. I am asuming that that also means to get a
    >decent print for whatever reason that that would be the minimum file
    >size depending on compression factor and a lot of other variables. At
    >that time I thought that a 3 megapixel camera would give roughly that
    >big of a file, now I found out you would need closer to a 6 megapixel
    >camera. Big difference in price especially for good quality camera.
    >Anyway what you recommend for me to get into the digital world? I know
    >that budget is the big factor i am limited to $500 canadian or about
    >$400 US. The cameras I have seen that I like the style and seem to
    >have good lenses are: Canon A80; Kodak DX6490; DX7440; DX7630; and
    >Panasonic DMC-LC70, all 4 to 6 MPixels...
    >Cheers
    >Doug


    Prizes are as follows: First Place, $300; Second Place, $200; Third
    Place, $100; Honorable Mention, $50. Up to five entries per month
    (digital image size: 50K–75K recommended, 100K maximum, JPEG format
    only; 3MP or larger images required if accepted for publication).
    Photos not chosen may be selected for “The Fix” feature


    The way I read this is a max 100 k jpeg taken with a 3 MP
    camera--which is the only thing that makes sense.

    So a 3MP camera should be fine for your application. As far as the
    size of prints you can have printed, I've turned out quite acceptable
    15 by 10 prints with my 3.3 megapixel camera after scaling them up to
    300 ppi with QImage or Photoshops bicubic routines.

    jpc
    jpc, Aug 16, 2004
    #8
  9. Doug

    Alan Meyer Guest

    "Doug" <> wrote in message
    news:...
    > ... you have to submit a minimum 3 MB jpeg file.


    As Roland pointed out, you misread the Pop Photo web page.
    It's 3 MP, not 3 MB, i.e., megapixels, not megabytes. All of
    your camera choices qualify.

    > ... The cameras I have seen that I like the style and seem to
    > have good lenses are: Canon A80; Kodak DX6490; DX7440; DX7630; and
    > Panasonic DMC-LC70, all 4 to 6 MPixels...


    A good place to see reviews of all of these cameras and many
    others is:

    http://www.steves-digicams.com

    Click "Camera Reviews" on the home page.

    In addition to very thorough specs, he gives knowledgeable
    opinions (perhaps a bit generous, but that's not unreasonable
    given what he's doing) and posts comparable photos from
    all the cameras that you can examine yourself.

    Alan
    Alan Meyer, Aug 16, 2004
    #9
  10. Doug

    Ken Scharf Guest

    Roger wrote:
    > On Mon, 16 Aug 2004 15:37:23 -0500, Roger <> wrote:
    >
    >
    >>Doug,
    >>
    >>You may also want to check the archives on this topic as there has
    >>been a ton of material written about this subject.
    >>
    >>You haven't said how big of a picture you intend to produce. I'm going
    >>to assume that you are interested in some sort of prints. Printing
    >>digital files at 300 ppi is a rule of thumb for "photo quality"
    >>prints. Many of the commercial systems use this measure.
    >>

    >
    > .. snip ...
    >
    >>I personally think you should be able to do a lot of great photography
    >>with a 4MP Canon A80 and they have a very attractive price point right
    >>now. Probably soon to be replaced.
    >>
    >>It's good to try to understand this, but it's not as cast-in-concrete
    >>as it may seem. My recommendation is to buy one that's "good-enough"
    >>to meet 90% of your needs and stays within your budget, learn what the
    >>processing and storage of images is all about and then go from there.
    >>
    >>Regards,
    >>Roger

    >
    >
    > Doug,
    >
    > After posting this, I started thinking more about this 3MP jpg
    > requirement. I have to admit that I think there are so many variables
    > that I don't have a clue what the magazine editors want or why they
    > want a 3MP jpg. I think I've completely missed you point. I know how
    > to "contrive" a 3 MP file using some of the variables you suggested,
    > but I don't know what 3 MP means as a "standard" for submittal.
    >
    > Sorry if I've added to the confusion, but I am confused by the
    > requirement.
    >
    > Regards,
    > Roger

    Some picture editing software (such as photo shop and the GIMP) allow
    you to change the jpeg file parameters dealing with the degree of
    compression. This would of course change the size of the file.
    Most cameras also have two or three modes of jpeg compression
    available which also changes the file size without changing the
    number of pixels in the image.
    Ken Scharf, Aug 16, 2004
    #10
  11. "Doug" <> wrote in message
    news:...
    > Hello, this is my 1st post in this group. I have been a hobby
    > photographer for 20 years or so, and have always used my trusty Pentax
    > MX. Now I want to convert to digital but after shopping around for a
    > while I am confused. I noticed that if you want to submit a photo to
    > Popular Photo and Imaging's best shots contest, you have to submit a
    > minimum 3 MB jpeg file.


    THE SUBMISSION REQUIREMENT IS:

    http://www.popphoto.com/article.asp?section_id=4&article_id=893

    "Your Best Shot" Entry Rules
    By The Popular Photography & Imaging Staff
    April 2004

    "...Up to five entries per month (digital image size: 50K-75K recommended,
    100K maximum, JPEG format only; <(note the semi-colon? The next sentence is
    a completely different subject.)

    THEN - ONLY for those selected/accedpted for publication... they continue
    with:

    ....3MP >>> or larger <<< images required if accepted for publication...

    I am asuming that that also means to get a
    > decent print for whatever reason that that would be the minimum file
    > size depending on compression factor and a lot of other variables. At
    > that time I thought that a 3 megapixel camera would give roughly that
    > big of a file, now I found out you would need closer to a 6 megapixel
    > camera.


    The key phrase is 3mPIXEL or larger. 1st, they don't want images that are
    shot on cameras that produce less than native 3mp image files. They don't
    want images shot on some El Cheepo 300x600pixels and they don't want images
    shot on mobile phone cameras that aren't any better then that for the most
    part.

    Then you said: "...you have to submit a minimum 3 MB jpeg file...."
    DON'T CONFUSE MP IMAGE SIZE WITH MB FILE SIZE - they are NOT the same thing.
    An image of 1600x1800 PIXELS is near to 3mPIXELS (2.88mpx) - the file size
    will be something completely different and from a jpg test file I am looking
    at with NO compression at all - it would be in the order of 0.9 MB (only).
    If I change the file from jpg to tiff the very exact same image with exactly
    the same number of pixels will have a vastly different file size. Ditto if I
    change the bit depth but keep it in a jpg format. If you read that
    submission notice again you will see that they are asking for 3MPIXEL images
    not 3MBYTE file sizes.

    Find a camera that will shoot an uncompressed jpg at better than
    1600x1800pixels (2.88mpx) and you have a camera that meets their
    requirement. Ideally here I would look for someting on the order of
    1800x2400 effective pixels. Don't worry about the computed image size in
    inches or cm - that is wholely dependent on how you res the image for
    printing and many cameras will only take images at 72ppi resolution -
    indicating that the print size will be massive. Simply changing the res to
    300ppi (or anything else for that matter) will upsize or downsize the image
    when printed full scale against the size in actual pixels and the selected
    resolution value. THUS...

    A 1600x1800 @72ppi image will tell you it is ca 22x25 printed inches when
    scaled at 100% BUT the exact same 1600x1800 image @300ppi will tell you that
    it is 5.3x6 printed inches when scaled at 100% - AND there is no re-sampling
    done to get there it is merely a scaling value for printing purposes.

    Journalist

    > Cheers
    > Doug
    Journalist-North, Aug 17, 2004
    #11
  12. Doug

    zuuum Guest

    Hi, Doug

    By 3Meg*P* file they mean the total numer of PIXELS, not the compressed jpg
    filesize. In fact, the rules say 100K max filesize for submission, so I'd
    assume they would want a larger file provided after your entry was selected
    for publication. A 3MP file compressed to 100K jpg would be a hell of a lot
    of compression and loaded with artifacts.

    It also says you can submit transparencies and prints. Almost any film
    scanner, even of 4 years ago will produce a qualifying image file if you
    wanted to retain your original transparency. They apparently want to insure
    that if your photo is a winning composition, they can publish the detailed
    print at a reasonable size (4x6inches) without interpolation. After all,
    how would it look if a photo mag published a "winning" photo that was blurry
    or could only provide for a 2-inch print.

    So, you could actually use yourt Pentax film cam, if you really preferred
    to. Any digital cam that is billed as a 3MP will do fine as long as you
    shoot at "fine" quality. But I find most captures from a 3MP ca produce
    more like 400K files at fine setting, so it appears to me they want a 100K
    submission and then require you to provide a larger file if your 100K file
    was selected as a winner for publication. Finally, choose the maximum MP
    rating you can afford. You can always reduce image size by resampling or
    shooting in reduced mode. Almost all of the point and shoot digicams allow
    for smaller image capture so you can fit more images on the same storage
    medium.

    And, good luck
    zuuum, Aug 17, 2004
    #12
  13. Doug

    Hunt Guest

    In article <CF8Uc.7875$>, says
    ....
    >
    >Doug wrote:
    >> Hello, this is my 1st post in this group. I have been a hobby
    >> photographer for 20 years or so, and have always used my trusty Pentax
    >> MX. Now I want to convert to digital but after shopping around for a
    >> while I am confused. I noticed that if you want to submit a photo to
    >> Popular Photo and Imaging's best shots contest, you have to submit a
    >> minimum 3 MB jpeg file.

    >
    >I'll be interested in seeing how this plays out. I have a recent "8 MP"
    >camera that gives two to two-and-a-half MB files in its 8MP-FINE mode.
    >Messed with and saved in PSD, files are in the 14 MB range.
    >
    >RAW (nef) files are 12+ MB (and won't yet open in PS CS...).
    >
    >Is there some magic threshold at 3MB for jpegs?
    >
    >
    >Frank ess


    Frank ess,

    To move on a tangent, PS CS has built-in RAW support for both Canon and Nikon
    RAW files (plus others). For PS7, there is a US$99 plug-in available. My nef
    RAW files open perfectly in PS CS, either from the camera's card (via USB), or
    from files copied to the HDD. What problems are you having with the nef's in
    PS CS?

    Hunt
    Hunt, Aug 17, 2004
    #13
  14. Doug

    GSW Guest

    FYI - You can get a Canon Digital Rebel SLR for $750 with a lens right now.
    That's what I paid for mine... new with US warranty.

    Brian C. Baird <> wrote in message news:<>...
    > In article <Xns9547ECC14AE05klotjohan@130.133.1.4>,
    > says...
    > > If you want something similar you want a DSLR. Then we are talking
    > > about $1000 and not $400. And if we are talking about a Pentax
    > > DSLR, we are talking about $1300 or so.
    > >
    > >
    > > /Roland

    >
    > Unless he can wait a few months for Pentax's announced "budget" dSLR for
    > around $900.
    GSW, Aug 17, 2004
    #14
  15. Doug

    Frank ess Guest

    Hunt wrote:
    > In article <CF8Uc.7875$>,
    > says ...
    >>

    ....

    >> RAW (nef) files are 12+ MB (and won't yet open in PS CS...).
    >>
    >> Is there some magic threshold at 3MB for jpegs?
    >>
    >>
    >> Frank ess

    >
    > Frank ess,
    >
    > To move on a tangent, PS CS has built-in RAW support for both Canon
    > and Nikon RAW files (plus others). For PS7, there is a US$99 plug-in
    > available. My nef RAW files open perfectly in PS CS, either from the
    > camera's card (via USB), or from files copied to the HDD. What
    > problems are you having with the nef's in PS CS?
    >
    > Hunt


    Thank you for your attention, Hunt.

    Virgin copy of PS CS looked at my CP8700 NEF files and said they were
    not the right kind. I had downloaded a 2.2 (?) update but not taken the
    time to remove the old and install the new. It works as intended, I'm
    certain, as I can see a lovely bee-on-a-fernblossom before my very eyes.

    Now I just must learn to fill the vessel, I reckon.

    I love this stuff.

    Thanks again.


    Frank ess
    Frank ess, Aug 17, 2004
    #15
  16. "zuuum" <> wrote in
    news::

    > By 3Meg*P* file they mean the total numer of PIXELS, not the
    > compressed jpg filesize. In fact, the rules say 100K max filesize for
    > submission, so I'd assume they would want a larger file provided after
    > your entry was selected for publication. A 3MP file compressed to
    > 100K jpg would be a hell of a lot of compression and loaded with
    > artifacts.


    Jepp - that is a possible interpretation. Unfortunately,
    the text i far from clear. So ... the problem still is
    - how large (in pixels) is a 100KB JPEG? A guess would
    be 640x480 pixels, i.e 250 KP. But, the text could really
    mean anything.


    /Roland
    Roland Karlsson, Aug 17, 2004
    #16
  17. Doug

    Doug Guest

    Wow this is a busy group! Great feedback, thanks everyone! Well on one
    hand I feel dumb for confusing mega bytes with mega pixels, but on the
    other hand I'm relieved that a 3 or 4 mega pixel would probably be
    good enough for me. I also somehow managed to enter the exact same
    subject in my 1st post as someone else and ended up in his thread,
    weird! Well I gotta go read up in Steves camera review webpage thanks
    again..


    Roland Karlsson <> wrote in message news:<Xns9548CB4F13A33klotjohan@130.133.1.4>...
    > "zuuum" <> wrote in
    > news::
    >
    > > By 3Meg*P* file they mean the total numer of PIXELS, not the
    > > compressed jpg filesize. In fact, the rules say 100K max filesize for
    > > submission, so I'd assume they would want a larger file provided after
    > > your entry was selected for publication. A 3MP file compressed to
    > > 100K jpg would be a hell of a lot of compression and loaded with
    > > artifacts.

    >
    > Jepp - that is a possible interpretation. Unfortunately,
    > the text i far from clear. So ... the problem still is
    > - how large (in pixels) is a 100KB JPEG? A guess would
    > be 640x480 pixels, i.e 250 KP. But, the text could really
    > mean anything.
    >
    >
    > /Roland
    Doug, Aug 18, 2004
    #17
    1. Advertising

Want to reply to this thread or ask your own question?

It takes just 2 minutes to sign up (and it's free!). Just click the sign up button to choose a username and then you can ask your own questions on the forum.
Similar Threads
  1. PEmpson181
    Replies:
    17
    Views:
    722
    Hans-Georg Michna
    Dec 1, 2003
  2. andy

    help! how many megapixels do i need?

    andy, Dec 28, 2003, in forum: Digital Photography
    Replies:
    67
    Views:
    1,781
    Keith Sheppard
    Jan 27, 2004
  3. Bill Hilton

    39 megapixels? 31 megapixels? Get 'em here ...

    Bill Hilton, Jul 16, 2005, in forum: Digital Photography
    Replies:
    7
    Views:
    340
    Bill Hilton
    Jul 18, 2005
  4. jdanield
    Replies:
    0
    Views:
    254
    jdanield
    Oct 17, 2012
  5. Rob
    Replies:
    0
    Views:
    388
Loading...

Share This Page