Hasselblad 555eld and Paintings

Discussion in 'Mirrorless Digital Cameras' started by matt_anderson|2, Nov 29, 2005.

  1. I have a hasselblad 555 eld with a phase one H20 back and a 40mm F4 FLE T CFE lens.
    I have some fine art and paintings that will need to be shot in the near future.
    This art may vary in size from 2' square to 4' square.
    I have access to Speedtron Flash heads as well as 1000w Fresnel Lights.
    I need to get exceptional color and detail for this job,
    can it be done with my tools at hand ? I'm afraid the 40mm lens won't keep the painting
    and art detail sharp all the way to the edge, and if I put too much distance between the
    camera and the art, I won't have enough resolution to maintain high amounts of detail.
    Is there an advantage to using the 1000 watt fresnel's on bulb mode vs using the high
    power flash strobes?
    Any pointers will be appreciated.
     
  2. The 40mm is the wrong lens for this application, regarding sharpness and flatness of field. Use an 120/4 Makkro or a 100/3.5 Planar. With this subject size, the Makkro has a slight advantage, but either would work. In a pinch, you could use an 80, but the corner sharpness might suffer. If you don't have another lens, borrow or rent one.

    Forget about the Fresnel lights - they cast a pattern. Besides, you need broad, even coverage, not a spotlight. The Speedotron heads will work fine. I suggest using a diffuser and polarizer gels on 12 inch (standard) reflectors.

    For maximum contrast (sometimes too much), use polarizing gels on the lights, oriented so that the plane of polarization is perpendicular to the flatwork. You can get suitable gels from www.edmundoptics.com, at a reasonable price, and cut them to fit the Speedotron gel holders.The light should strike the flatwork at about a 45 degree angle, far enough away so that the illumination is uniform within about 1/4 stop. For more contrast, also use a polarizer on the camera, with the plane of polarization perpendicular to the imaginary line between the lights (i.e., vertical).

    Use a flash meter on the flatwork and don't forget to compensate for the camera polarizer.
     
  3. Agree with some of things Edward I writes with some exceptions: use polarizing gels on the lights, oriented so that the plane of polarization is perpendicular to the flatwork.
    Not sure what he means by this. you wantthe polarizing gels on the lights oriented in one direction -- horizontally perhaps --and the polarizing filter o nthe camera oriented perpendictual to that direction., This is known as cross polarization and will eliminate virtually all glare on the surface of the woork beig photographed. Sometimes you want a little glare to show the texture in an oil painting and you achieve that by slightly rotaing the polarizing filter on the lens.
    ...far enough away so that the illumination is uniform within about 1/4 stop.
    My experience is that you want the illumination even to within a 1/10th of a stop. from center to corners and edges. at 2/20ths I start to notice the uneveness.
    Also make sure you include a Gretag-Macbeth Color Checker card, one of the new ones, in the frame as a standard color reference and neutral balance check.
     
  4. Light reflected from a dielectric surface (e.g., a painting) is partially polarized in a plane parallel to that surface. The angle of incidence for maximum polarization is approximately 37 degrees (close enough to 45 degrees).

    If the surface is smooth, light from specular reflections just bounces off the other side into space. Most paintings have some surface texture, whether canvas, paper or oils, so that some specular reflections are bounced in the direction of the camera.

    If the light source is polarized in a plane perpendicular to the plane of the subject, these reflections are reduced to the extent that they would be otherwise polarized by reflection (up to about 40 percent). Some of the polarized source light is still reflected into the lens. You can further reduce the specular reflections by using a polarizer on the lens. You can adjust the angle of this polarizer to see more or less of the surface texture. Using a polarizer only on the lens will have little effect on glare when looking directly into the work to be copied.

    About half of the light is reflected from inside the surface, and is diffuse, non-polarized, with high contrast, color saturation and definition. Polarization removes most of the glare, which reduces contrast and shows surface texture.
     
  5. Light reflected from a dielectric surface (e.g., a painting) is partially polarized in a plane parallel to that surface. The angle of incidence for maximum polarization is approximately 37 degrees (close enough to 45 degrees).
    Methinks you need to define angle of incidence. Most people I know go from the normal (not that it matters if you pick 45 deg....) And if you want to get really picky, that 37 deg (I'd call it 53) is really for water whereas what you really need depends on the index of your substrate.
     
  6. You are correct. The angle of incidence is measured from the normal. The 37 degree value is actually the complement of the angle of incidence for water. Polarization does vary with the angle, refractive index and/or the dielectric constant ratios at the boundary layer. Where are my notes on solid state spectroscopy, only 30 years ago?
     
  7. It gets better, I have now learned that I also have access to a Betterlight 6k2 enhanced
    Scanback, a toyo large format camera, and several Schneider lenses from 100 - 180 mm !
    I may consider using this back instead, I'll have to figure out a way to light the pieces in a
    uniform manner. I've heard good things about the Scanbacks. It has a scsi interface, and is
    Mac OSX 10.4.3 compatible. P.S. I'm considering picking up a Nikon D200 ( I have an
    assortment of nice Nikkor lenses at my disposal, but, I wonder if the price is justified worthy
    over the D70s, it will be for my own personal enjoyment, and pursuit of Ansel Adams esque
    type photo's)
     
  8. "dialectric surface...angle of indicidence...complementary angles..."

    Have you guys ever actually done this? You're certainly struttin your bad tech self...except it's not all that hard.

    I've copied artwork for years using 4 Lowell Tota Lites with polarizing material and a 4x5, a Hasselblad, and a Nikon F...

    Set the lights up at 45 degrees to the artwork. Adjust / feather the lights to get uniform illumination - and Ellis is right - on critical work you can see 1/10 of an F-stop dfference in illumination between the center and edges.

    I use a PhotoResearch Litemate III footcandle meter and try to get not more than plus/minus 5 fc over the entire surface. The general illumination level is in the 250 - 300 fc range.

    Look through the viewfinder and adjust the polarizer to give the effect you want. On flat paintings (minimal brushstrokes) I maximize the polarization to eliminate all of the reflections. If the work is for an artist to enter a show, with heavy brushwork I like to leave some "sparkle" on the paintings so you're aware of the brush strokes. However, I always shoot several versions and let the artist choose the one they want.

    If it's for museum catalog work, I talk with the show curator to see how they want the reproduction. Some want all paintings totally flat, no sparkles. Others will want some detail in the brush strokes.

    If shooting 4x5, I try to use a 180mm or longer. I have used my 135mm in situations where I could not get back far enough with a really large piece of work.

    Likewise, with my Hasselblad, I try to use 80mm or longer - but, I have used my 50mm FLE in a pinch. Just make sure you're level, and parallel / plumb with the artwork looking directly at the center.
     
  9. Have you guys ever actually done this? You're certainly struttin your bad tech self...except it's not all that hard.
    My, my, touchy, aren't we! Yes I have done this, though not for photographic purposes (weird lab experiment -- technically more demanding, fortunately no call on artistic talent), and no, it's not that hard. The point of my post was to clarify terminology used in error (especially as Edward Ingold clearly knew better) and to point out that Brewster's angle is not actually a fixed magic angle (though it's pretty close)
    To the original poster: you seem to favor shorter focal lengths for this type of work. What's the reasoning behind this? Lens availability? Working space? A bit long of normal (180-210 in 4x5, 100-120 in MF) would reduce falloff and perspective issues.
     

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