6MP Nikon D100 - good enough for critical 24" x 42" advertising posters?

Discussion in 'Nikon' started by borkomile, Sep 4, 2005.

  1. borkomile

    borkomile Guest

    X-No-Archive: Yes

    I am one of those old mares who has stuck clear of digital, apart from
    a convenience 8MP small-sensor non-SLR P&S which is fine for what I use
    it for.

    A friend of mine uses a Nikon D100 and a couple of AF-D Nikkor zooms.
    He has asked my opinion as to whether that is suitable equipment for an
    assignment to photograph some objects for ADVERTISING POSTERS. The
    poster sizes will be 24 inches x 42 inches (2 ft x 3.5 ft). The
    subject matter will fill almost all of the area of the poster.

    The posters will typically be viewed from a distance of a foot, in shop
    windows and on display stands.

    While I can't tell you what the subject is, pin sharpness of the end
    result is critical for the assignment. Sharpness is an attribute of
    the very thing being advertised.

    The D100 is a 6 megapixel camera, making 3008 x 2000 pixel images in
    its highest resolution mode. It is certainly better than my 8MP P&S
    due to the larger sensor size / better noise, superior lens(es) e.t.c.

    But I just can't see how the D100 can cut it to reach 24" x 42". Even
    assuming that he fills the frame pretty well with the subject so there
    is only a 20% loss through cropping (given the nature and proportions
    of the subject, that would be excellent), that would mean he would need
    to fill 42" with 80% x 3008 = 2406 pixels. That means the "ppi
    resolution" would be no more than 2406/42 ppi = 57 ppi, or just over 2
    pixels per mm.

    Sharpening or interpolating (creating pseudo-detail) software won't
    help much, given the subject.

    I think that 57 ppi is far too little, given the likely viewing
    distances. The general wisdom is that 300 ppi is best for a hand-held
    8" x 10" and 150 ppi may be acceptable for critical work with a viewing
    distance of over a foot. But 57 ppi is nowhere close to 150 ppi, and I
    think the image will look quite pixellated or dotty and, when
    interpolated for printing and the end result viewed as a poster,

    Given that the advertising posters are aimed at an audience who will
    come up to them and look at them closely (some from closer than a
    foot), can 57 ppi be enough?

    Oh I know ppi and dpi are not the same.

    Please tell me your views. Will the D100 cut it for the assignment? I
    think a modern 11+ MP SLR just might, and certainly if I could stretch
    to a digital back for my Hassy it could. My instincts (more reliable
    than my maths, which isn't too good) would be to shoot it on Kodachrome
    25 (I have a brick holed away in the fridge) or Velvia 50 (grain being
    less important than sharpness for this subject - a little grain may
    even be flattering) or similar, and have it drum scanned for good
    measure. I'd use a 6x6 on a 'pod. Just maybe a 35mm with a good prime
    lens too.

    If I am right, how do I diplomatically tell him this? I value his
    friendship and he does not take criticism well. The assignment means a
    lot to him, and I don't mind loaning him my analogue gear (a modern
    Hassy and/or an almost brand new F6).

    Or is my friend right, and my maths wrong as usual, and the D100 will
    do the job fine?
    borkomile, Sep 4, 2005
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  2. borkomile

    borkomile Guest

    X-No-Archive: Yes

    I forgot to mention that the subject CANNOT be photographed in sections
    which can then be pasted together.
    borkomile, Sep 4, 2005
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  3. borkomile

    Alan Browne Guest

    No. If they were viewed from 10 - 15 feet or so, no problem.

    Alan Browne, Sep 4, 2005
  4. borkomile

    UC Guest

    Did somebody pay you to write this crap?

    UC, Sep 4, 2005
  5. borkomile

    Stacey Guest

    If he won't listen, let him find out the HARD way. There is no way that dSLR
    can produce a print that size that will look good viewed 1 foot away. Even
    6X6 is pushing it IMHO.
    Stacey, Sep 4, 2005
  6. borkomile

    Justin Thyme Guest

    If the audience will be as critical as you are suggesting, the simple answer
    is no. I doubt any small format (ie 35mm film or digital) will do the job.
    Medium format should be just about there, but I'd be starting to think maybe
    he should be looking at a 5x7. Realistically though, will people be viewing
    such a large image from such a close distance that critically? I would find
    it highly unlikely people would be inspecting such a shot from 1 foot.
    Also, how will it be printed? most commercial large format poster printers
    have a pretty low effective resolution.
    I recently had an assignment for a 24x48 poster to be used in an instore
    display, that I shot on Fuji Superia 35mm. The film was scanned at
    3300x2200, cropped top and bottom (24x48 would be equivalent to a 32x48
    print if the full frame was used), and printed on an Epson 7600. It is not
    critically sharp, but it appears extremely good at a typical viewing
    distance of about 2-3 feet. This is a very similar resolution to a D100, so
    I would expect it to be similar quality to a D100 image printed at your
    smaller target size.
    I would suggest your friend mocks up a version of the shot, prints it at the
    required size, and checks if that is going to be sufficient quality.
    Justin Thyme, Sep 4, 2005
  7. Science (and in particular Math) is *exact*. Don't be misled by
    reality! :)

    Kidding aside, your math looks wrong to me -- the D100 has 3000 x 2000
    resolution; that would be the form factor of a 36 x 24, but since you
    require 42 x 24, that would mean you end up using only 3000 x 1714 of
    the available resolution.

    The physical (spatial) resolution on the print will be:

    DPI = 3000 dots /42 inches = 71 dots/inch

    71 dpi is the resolution of a fairly good monitor, where the image will
    look *much* better than anything taken with 35mm film (well, maybe if
    you use ISO 64 or ISO 25 -- if those beasts do exist -- then it would
    be a close call)

    Provided that the printing is done properly (in particular, provided
    that the printer does a digital oversampling to its native resolution
    of maybe 300 or 600dpi, as opposed to printing SQUARES of a 70th of an
    inch), it should be fine.

    I have ordered 6x4 prints from a 640x427 image (for testing purposes),
    and the print is impeccable (as impeccable as the best of 35mm film
    images I've taken). Ok, that's a bit above 100dpi, but 71dpi is in
    the same order of magnitude -- I think it should definitely look
    good from about 1 foot (and I mean *good*, not just ok). Provided,
    of course, that he has good lenses and makes good use of them (i.e.,
    use the aperture that yields sharpest results, trading-off between
    diffraction and depth-of-field, etc.)

    That, or, as already suggested, let him find out the hard way and
    update his camera to a D2X with ED lenses ;-)


    Carlos Moreno, Sep 4, 2005
  8. borkomile

    Justin Thyme Guest

    If you think 640x427 printed on 6x4 is impeccable, you need to get your eyes
    checked. If you think it is as good as 35mm film, your 35mm camera needs
    some serious work.
    Justin Thyme, Sep 4, 2005
  9. Credibility of the advice you get is important in assessing the replies.
    24" wide is OK using a decent algorithm for the enlargement. You'll see
    little discernible loss of detail at 10" however...

    42" long is the problem. A straight enlargement will produce 24" by 36"
    image. If you intend to get the extra width by cropping from the 24"
    side, a 6 megapixel image is not going to give you what you want.

    http://www.canvasphotos.com.au/enlarge-example.htm is an example of what
    you can expect to get. A Nikon image taken with a decent (Nikon) lens
    will be better than this one but not so much better that you can
    increase it 20%.
    Pix on Canvas, Sep 4, 2005
  10. borkomile

    Bob Williams Guest

    Your friend may be less critical of image quality than you are.
    If you want to show him what an image printed at 57 ppi looks like, just
    take a picture with the D100 and crop out a section that is 456 x 570
    pixels and print it as an 8x10.
    Just for grins, RESAMPLE the 456 x 570 pixel image, threefold, to 1368 x
    1710 and print it at 8 x 10 (171 ppi) and see if it looks any better.
    A simple experiment is much more effective than sophisticated conjecture.
    Bob Williams
    Bob Williams, Sep 4, 2005
  11. borkomile

    jbarker Guest

    There's an up-sampling software called Genuine Fractals. Try it out
    jbarker, Sep 4, 2005
  12. borkomile

    Mike Warren Guest

    I found no better results from GF than from stair step interpolation and
    CS2 now uses stair step internally.

    Mike Warren, Sep 4, 2005
  13. borkomile

    borkomile Guest

    X-No-Archive: Yes

    Hi Carlos,

    Thanks for your answer.

    Kidding aside, the only difference between your workings and my
    workings is that you are confusing ppi and dpi and you had forgot I had
    written there would be a "20% loss through cropping" in both length and
    breadth. 80% x 71 ppi = 57 ppi which was my number.

    It is unrealistic to assume that 100% of the photographed image is used
    in the poster, so the adjustment for cropping is normal. By only
    allowing 20% I am assuming the framing is tight.
    I am afraid but I have to agree with Justin Thyme's reply to you on
    this one, Carlos. Justin told you:
    "If you think 640x427 printed on 6x4 is impeccable, you need to get
    your eyes checked. If you think it is as good as 35mm film, your 35mm
    camera needs some serious work."

    I am sorry if your feelings are hurt, Carlos. 640 x 427 printed on 6"
    x 4" is 107 ppi, and 107 ppi viewed from a foot is B L U R R E D. Even
    200 ppi is often (depending on subject) not enough for critical viewing
    at that distance.

    And you in effect are saying that 57 ppi will be good enough?
    borkomile, Sep 4, 2005
  14. Oh, you didn't mention this detail in your initial reasoning, so I
    thought it was a mistake that you had applied the reduction in the
    3000 part, when it should be in the 2000 part (if we assume that we
    are going to apply the minimum cropping required to get a form factor
    of 42 x 24). (more on this below)
    Putting matters of opinion aside, wrong on both counts. (so, the only
    part that is up for discussion on that phrase is the "if you think"
    part; that is, the opinion part is the only part where you could be
    right in disagreeing).

    Those tests were done around a time where I had my eyesight checked
    TWICE within the same week. The reason was that I was having headaches
    that I suspected were related to my eyes, so I went to an optometrist;
    when she told me that my eyesight was absolutely perfect (and tried
    to justify why the headaches could be normal given the stress that I
    was putting on my eyes), I assumed that she was a mediocre optometrist,
    so I made an appointment with another one, just to have it confirmed
    that my eyesight was *perfect* (this time I insisted -- I asked him,
    but are you sure? Did you check for ability to see at a close distance,
    etc. etc.? The guy practically laughed at me, told me that I was able
    to see the slightest minimum thing he showed me).

    Seriously, I'm not bulshitting you :)

    And as for my camera needing revision, I seriously doubt it; I have
    a Nikon F80 bought less than 5 years ago -- when I bought the camera,
    I bought two lenses that costed me close to TWICE the price of the
    camera (and again, these tests I did were about two years ago, so
    we're taking about comparison to shots taken during the first two years
    of the camera's lifetime; I've done 24 x 36 enlargements of these
    prints, and you *can see the grain* for an ISO 100 film, so I really
    think that's sign that the camera is (or was, at least) not in urgent
    need of any work.

    I don't mean to sound dense or stubborn or show-off -- I just want to
    insist (and now my disclaimer: I don't want to hurt your or anyone's
    feelings ;-)) that lots of people like to claim that they can see
    the difference between a one-million-dots-per-inch print and one of
    half-a-million, when indeed is just wishful-thinking self-comfort...
    (ok, the one-million-dpi was obviously a figure of speech, but you
    know what I'm trying to say).

    Another issue that is kind of a pet peeve of mine is the fact that
    many people don't seem to quite understand the issue of DPIs when
    printing. I have explained it numerous times in this newsgroup.

    If you print something at a low resolution of, say, 50DPI by drawing
    squares of 1/50th of an inch with the same color, then *that* will
    look horrible (horribly bad). If you do an interpolating oversampling
    of the image to bring it to a resolution of 300 or 600 with an
    effective "information resolution" of 50 dpi, the result will look
    infinitely better than the other one.
    Yes, I'm hurt, and *very very* hurt and you should be sorry for
    that!! (hehehehehe ;-))

    Just to make sure: I'm totally kidding, ok? -- I enjoy a healthy
    discussion where people are not afraid to express their views (you
    know, either extreme is bad: if people are insulting each other,
    that's unhealthy, but the other extreme, where people don't say
    what they think just because it might hurt the other one's feelings
    is boring and thus equally unhealthy).
    I was basically saying that if a D100 does not do the job, then no
    35mm film camera will (again, except maybe if we consider ISO 25
    or ISO 64 slide film -- provided that the lenses are top-of-the-top
    quality and the whole camera is in impeccable shape).

    I now think that you were comparing a D100 vs. a medium or large
    format film photography? (if that's the case, I'm 100% not entitled
    to an opinion there, since I have zero experience with anything
    other than 35mm photography -- I would like to hear some more about
    it, if that's the case).

    I also missed (from your initial post) the fact that sharpness (of
    the subject) is part of what is being advertised. But again, if the
    other option is a 35mm camera, then my bet is still that the D100
    will do a *better* job (if that job is *good enough* is another

    I'll start working on some more convincing tests (for printing at
    various resolutions) :)


    Carlos Moreno, Sep 4, 2005
  15. A James Russell shot from a Fuji S2 once sat on one of those huge billboards
    in Times Square. I've had a Canon 10D image used for 60x40 inch billboards
    on eye level display in malls (and it had been cropped by approx 20% too).
    Like your friends potential commision these posters could be viewed very
    closely by shoppers. If the subject requires great detail - something like
    an architectural showpiece - then 6MP's not even close. From what you have
    described this may well be the case. He could hire a Nikon D2X (or even a
    1DS mkII and a lens). But for many subjects and uses, including most that
    feature people, 6MP will really be fine at 24"x42" on a poster if processed
    accordingly. If he does try it with a D100 then advise that he applies no
    sharpening at all. Sharpening before resizing is what will create the
    aliasing & pixelization you're concerned about. Capture in raw and process
    in ACR if possible. In-cam JPEGs and some raw converters sharpen even when
    set to minimum or no sharpening. Resizing from a clean unsharpened 6MP
    capture can be taken to extreme sizes if necessary. The 'laws' of acceptable
    inkjet resolutions as well as shaprening thechniques really do not apply for
    Simon Stanmore, Sep 4, 2005

  16. Stair step interpolation is one of digital processing's greatest myths. It
    degrades the image. Try it out on an unsharpened image and compare with a
    one step bicubic up sample and you'll see an obvious artificing on the stair
    stepped version (especially around contrast edges). GF's resizing is a
    matter of taste as it can render an image in an odd way, a bit like
    painting. One step bicubic is the cleanest way to up sample
    Simon Stanmore, Sep 4, 2005
  17. borkomile

    Roger Moss Guest

    Nobody has yet mentioned the all-important output issue - if it's for a
    poster, then are they going to silk-screen print it? If so, the dpi
    requirements/possibilities of the image will be very different from those of
    finer printing methods like litho or even commercial inkjet.

    Get closer to the average billboard poster than it's intended to be viewed
    and you'll be surprised just how lo-res things look...

    Roger Moss, Sep 4, 2005
  18. borkomile

    Alfred Molon Guest

    Not with 6MP, but you might use a panorama technique to stitch together
    a higher resolution image. One of my panoramas (stitched out of 8MP
    images) was used for an advertising campaign in Singapore (magazines,
    newpapers and billboards).
    Alfred Molon, Sep 4, 2005
  19. borkomile

    Mike Warren Guest

    I thought someone would disagree. That's the whole problem here.
    You can't get something for nothing.

    One step bicubic (especially at smaller magnifications) will create
    a smoother result. The problem is that the viewer would like to perceive
    more detail. The artefacts created by stair step and GF help with the
    illusion of more detail. GF applies a pseudo randomisation to the
    artefacts, supposedly to create a more pleasing result.

    To me, on the few pics I tried it on I preferred stair step.

    I guess that's is why the arguments will continue as long as we try
    to invent data where none exists. Individual tastes differ. :)

    Mike Warren, Sep 4, 2005
  20. We photographers are such sleazes. Film photographers use grain to create
    the illusion of detail and digital photographers use GF.

    David J. Littleboy
    Tokyo, Japan
    David J. Littleboy, Sep 4, 2005
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