Analogue to digital conversion headache

Discussion in 'Digital SLR' started by Siggy, Mar 18, 2005.

  1. Siggy

    Siggy Guest

    As an enthusiastic, but somewhat clueless amateur, I wonder if I could call
    upon the great wisdom round these parts?

    I am having trouble deciding on a digital camera and lens combination to
    replace my fairly ancient but trusty analogue workhorse combination. I own a
    Minolta 500si body to which I mated a Sigma 50mm/f2.8/AF/Macro EX lens,
    which give me nice undistorted sharp pics! This is used on an RR Beard copy
    stand with a couple of 625watt floods diffused and reflection-shielded with
    resin
    polarisers to remove the reflections from framed artwork behind glass. On
    top of that, I use a 55mm Hoya circular polarising filter on the camera
    lens. So you can see why I need a fast lens!

    Obviously working with RAW images is the way to go, as I can imagine I would
    need to do some extensive post-processing work with Photoshop. However, I am
    not very savvy with lens matters, and am a bit limited with the old budget.
    I am aware of the limitations a digital sensor's field of view (?) has,
    compared with the 'full frame' characteristics of the 35mm analogue camera.
    As I use a copy stand with pretty restricted vertical height limits, I think
    I am going to run into problems with a 1.5 - 1.7 crop factor inherent in
    non-full frame sensors of semi-pro cameras, no? I sometimes need to
    photograph pretty large paintings, and if they exceed about 30"x24" then I
    have to insist that the painting is removed from the frame for shooting
    horizontally on a tripod. But that can cause me loss of work, as many
    paintings just cannot be removed easily from their frames.

    I also need a camera capable of resolving to quite high pixel counts, so
    that I can print out at A3 size without additional interpolation. It must
    also be very good at achieving commercial levels (not archival quality) of
    colour and tonal reproduction. I often have to make post-processing
    corrections without the benefit of the original work to refer to, so the
    least guesswork involved with colours and tones, the better and more
    productive I shall be. :)

    I have in mind the following possibilities:

    Would I be able to use my existing lens on say the new Minolta Maxxum/Dynax
    7D?

    On a bang-per-buck basis, I am also kind of tempted towards the Sigma SD10
    with the foveon X3 sensor on the basis of both colour definition; sharpness
    and the apparently excellent SPP processing software with the Light-fill
    feature. (I downloaded the software and tried it out on a sample image) I
    know this camera makes many round these parts look for a sick-bag, but
    bearing in mind it will have a pretty dedicated and restricted use in a
    studio, I shall not need to invest too heavily in a multitude of lenses and
    feel stuck with them. That said, it has one of the most restrictive (for my
    purpose) crop factor of most cameras in this range. (@ 1.7 IIRC)

    I had better stop there, or I'll end up answering my own questions, God
    forbid! Sorry for the ramble but my head hurts with all the trying to get to
    grips with this technology. :-(

    Kind regards

    Nigel
     
    Siggy, Mar 18, 2005
    #1
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  2. Siggy

    Alan Browne Guest

    Yes. The following is hastilly done, but should give you a good feel:

    (Maxxum 100 f/2.8 macro lens (not at macro closeness); In camera JPG /
    Fine, two softboxed strobes @ f/8, ISO 100)

    Post processing: Unsharp mask only.

    small v.
    http://www.aliasimages.com/images/KM7D/ColBill_SM.U.jpg

    (100% crop from above, view it at 100%, 800 KB)
    http://www.aliasimages.com/images/KM7D/ColBill_FD.U.C.jpg

    Full detail (large file, 2.5 MB), view it at 100%
    http://www.aliasimages.com/images/KM7D/ColBill_FD.U.jpg

    Crop issues: I'm sure you can work out an accurate means of shooting
    framed works at any distance with them hanging flat against a wall. Or
    find means to extend the height of your copy stand.

    A3 (297 x 420) should print well at about 180 dpi without interpolation.
    You're welcome to print the above FD.U file as a test. (Bear in mind
    that the banknote was not perfectly flat for the shot, nor the lens
    critically centered and aligned).

    The only issue with the SD10 is that it is in fact a 3.4 Mpix
    resolution. Some people feel that the colors are off in some areas.

    Cheers,
    Alan
     
    Alan Browne, Mar 18, 2005
    #2
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  3. Siggy

    Siggy Guest

    Alan Browne wrote:

    Wow! What a quick and detailed response. I am humbled indeed. :)
    That is a lot to chew over and digest, but just wanted to say a quick word
    of thanks for your kind interest, and will post back any further opinions on
    that asap.

    Kind regards

    Nigel
     
    Siggy, Mar 18, 2005
    #3
  4. Siggy

    andrew29 Guest

    Yes. You're only foing to get a 29 degree FOV with that 50mm lens.
    OK, that's a minimum of about 200 DPI. 3300 x 2338 pixels. About 8
    megapixels.
    a. It doesn't have the resolution you need at 3 Mpix.
    b. It doesn't have the colour rendition you need.
    Which you certainly aren't going to need on a copy camera.

    Andrew.
     
    andrew29, Mar 18, 2005
    #4
  5. Siggy

    Alan Browne Guest

    I would have hoped that your interest was in fact in the rest of the
    post, not the Sigma bit.
     
    Alan Browne, Mar 18, 2005
    #5
  6. Siggy

    Siggy Guest

    I was indeed. I had hoped my snippage comment further up would have
    indicated as much. ;-)

    Now to your info.

    Firstly then, the Sigma is a non-starter. Ta!

    Secondly, you stated "(........... two softboxed strobes @ f/8, ISO 100)"

    Now that's interesting because I have the matter of suitable lighting for
    digital cameras in my mind, but thought it would be too OT for this group.
    However, since you offered advice, can I just clarify that you mean 'strobe'
    to be a flash-type light as opposed to the always-on flood-type which I
    currently use? If so, why should I change my current lighting setup? (I am
    thinking cost consequences here)
    Further, I seem to recall a white paper written by Betterlight on this
    subject, and their eventual recommendations were to use fluorescent lighting
    with a couple of filters (daylight AND tungsten, IIRC) to counter the
    metamerism effect on certain colours when using digital sensors. Any
    comments?
     
    Siggy, Mar 19, 2005
    #6
  7. Siggy

    Siggy Guest

    Hmm. I don't suppose you could also let me have the FOV (in degrees) of the
    lens in my existing setup, could you? :)
    Ok. Minolta D7 seems a bit weak in that respect then. Are we looking at the
    Canon 350D here, I wonder?

    (on Sigma SD10)
    Yup, gotcha. Thanks.
    I mentioned that as I have always found (in an image containing significant
    dark or shadow areas) it difficult to get the scanner to extract as much
    detail from the dark areas of the photographic print without blowing out the
    delicate highlights. However, I forgot that I shall be bypassing that stage
    with a digital camera, so I stand corrected. Thanks.
     
    Siggy, Mar 19, 2005
    #7
  8. Siggy

    Alan Browne Guest

    You don't need to at all. For flat work continuous ligthing or flash
    can be used equally well.
    I'm not sure why they would say that. Flourescent is non-continuous in
    spectrum and will not return the colors of artwork faithfully. ( I'm no
    expert in this, but that's the way it would seem to me). Tungsten is
    continuous but weaker at the shorter wavelengths, stronger at the longer
    wavelengths.

    For flat work I would guess that tungesten alone with the digital camera
    body set to 2800K would be very good. (I've been shooting a lot of
    tungsten photos and the whites look white.

    Two flashes, and the camera set to 5500K is probably better than
    tungsten for flat work, and softboxing them gives very even illumination
    at the subject. Harder to use polarizers, but with digital you can
    simply chimp and histo your way to the right exposure. Capture RAW to
    really have a working file for post-proc.

    Cheers,
    Alan
     
    Alan Browne, Mar 19, 2005
    #8
  9. Siggy

    Alan Browne Guest

    For A3 the Maxxum 7D will do fine. So will the the 350D and I doubt you
    would see much difference in the output images between the two. The
    crop factor of the 350D is 1.6 (v. 1.5 for the 7D) and that will make
    your larger frame copy work more difficult.

    I don't want to sound like a shrill defender of the 7D, but given your
    requirements I believe the output will be equally good to the eye as the
    350D and less difficult to work with.
    Most particular if you capture RAW.

    Cheers,
    Alan
     
    Alan Browne, Mar 19, 2005
    #9
  10. Siggy

    Siggy Guest

    Two words - 'Cobalt Blue'. :) It seems that this (often used artists
    pigment) is extremely susceptible to turning purple under tungsten light,
    and conventional methods to correct this only leads to creation of other
    colour changes in other pigments. I have now found the white paper by Robin
    Myers and provide the link here, should this interest you.
    Website link only:
    http://www.rmimaging.com/information/information_index.html
    and for the pdf itself::
    http://www.rmimaging.com/information/color_accurate_photography.pdf
    Thanks again.
     
    Siggy, Mar 19, 2005
    #10
  11. Siggy

    Siggy Guest

    Aaah, so it will!!
    Then there's the cost difference. Minolta has started selling in the UK here
    for just a smidgen under £940 (US$1800 approx) body only, but I can use my
    existing lens. The Canon 350D body for UK£640 (US$1230) + a suitable lens at
    around UK£250 (Sigma) = £900 approx. Not much in it cost wise I guess, so it
    seems Minolta wins on FOV ease of use. Ho hum, choices, choices. Now if
    Minolta could only produce a version without the expensive anti-shake
    implementation, I'd be laughing! Dream on Nigel. :)
    Yes, indeed.
     
    Siggy, Mar 19, 2005
    #11
  12. Siggy

    Alan Browne Guest

    Siggy wrote:

    I hope your photography extends beyond copy work...
     
    Alan Browne, Mar 19, 2005
    #12
  13. I thought that was its main selling point?

    Since they already worked out how to do it in the A1, A2 and A200, I would
    imagine that the extra costs either for hardware or development of
    software were pretty small.

    David
     
    David J Taylor, Mar 19, 2005
    #13
  14. Siggy

    Alan Browne Guest

    Thanks, I'll look. But I would bet that flash would solve all your issues.
    Particularly for sports photogs. The 'peeking' at the images in the
    monitor while at the event to verify exposure and timing. Impossible
    with film, a bit of a good/bad habit with digital. (Bad if overdone,
    good if used to verify for blown/excessive highlights or dead shaddow
    areas).

    I just played with shooting and using the PC as monitor and storage
    while shooting, that could be addictive. Now if only it could be
    wireless... (The supplied USB cable is very short, so not an easy way to
    work).

    Cheers,
    Alan
     
    Alan Browne, Mar 19, 2005
    #14
  15. Siggy

    Siggy Guest

    Actually, I do very little recreational photography, other than occasional
    holiday-type snaps for which I use an old and trusty Olympus Camedia C840L
    1.3mp complete with a whopping great 4 megabyte storage card! I also use
    that for taking shots of general scenes for the art studio's website, and
    that is more than adequate for my needs. ;-) I think I was a little put off
    by the quality of my film-based experiences in the more distant past, but I
    have a nagging suspicion that a good SLR digital is gonna rekindle some
    dying embers.............
     
    Siggy, Mar 19, 2005
    #15
  16. Siggy

    andrew29 Guest

    image size
    2 atan ---------------
    2 * focal length

    = 39.6 deg.
    Could be. You might be able to get way with 6 Mpix, though. It all
    depends on how much total image detail you really need on that A3
    page.

    Andrew.
     
    andrew29, Mar 19, 2005
    #16
  17. Siggy

    Siggy Guest

    Not for me it ain't. I don't need anti-shake on a sturdy RR Beard copy
    stand, you see. ;-)
    However, as I have already intimated to Alan a little earlier, a good
    digital camera may well rekindle my interest forn recreational photography,
    in which case that may prove a boon indeed. And by then, I'll be able to
    afford a full-frame sensor camera for the studio work! lol
    Oh, right. Well, every little helps. :)
     
    Siggy, Mar 19, 2005
    #17
  18. Siggy

    Siggy Guest


    <G U L P> ~10 degrees that's quite a loss.
    I'm gonna have to borrow one from somewhere then to see what I'm letting
    myself in for, in terms of increasing the distance/height between camera and
    subject. This is more serious than I thought, at least at first glance. I am
    very grateful to you, Andrew.
     
    Siggy, Mar 19, 2005
    #18
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