By Dennis Davis
www.DavisPhotographic.com

As photographers continue to abandon film for digital capture, the graphic design firms and advertising agencies must change with them. For example, when I attended graphic design school in the eighties, we were taught that image file sizes should be twice the size of the printed line screen, such as 300 dpi for a 150 line screen. This was to allow for the grain in film. However, with digital capture there is no film grain, and the new digital capture standard is 1.5 times the line screen, or between 225 to 240 dpi. See http://www.asmp.org/pdfs/inside_the_revolution_RA.pdf for more information on digital capture and dpi.

The expected standard for quality photograph for reproduction in the eighties was medium format or 4 X 5 large format. One of my first professional shoots (1983) was a big thanksgiving food display, which I shot with my Crown Graphic 4 x 5 and my Hasselblad 500 CM. I was just starting out, and could not afford enough lighting gear to get the depth of field I needed with my 4 x 5, and the background objects were soft. I did not repeat that mistake! The client insisted that his 11" x 17" menu cover needed to be reproduced from the 4 x 5 transparencies, until the art director convinced him that the medium format version had more depth of field. A 35 mm transparency would not have even been considered by this client. 35 mm images were o.k. for up to one page or so, but for a poster, two-page spread or larger a graphic designer would almost always choose a medium or large format image instead of a 35mm image if given the choice.

Has the digital explosion impacted the place of medium format cameras, and are they still the best choice for quality reproduction? Until the digital revolution, medium format cameras were the first choice of wedding and portrait photographers. These photographers made more money by selling large prints, and large prints required large negatives. With the onset of the digital revolution, wedding and portrait photographers are abandoning medium format cameras and switching to Canon and Nikon DSLRs in droves. As a result, medium format camera brands are disappearing rapidly. Bronica , Contax, Pentax and Rolleiflex have ceased production most or all of their medium format lines in the last few years. This left Hasselblad and Mamiya as the two primary producers of medium format cameras. Earlier this year, Mamiya's parent company in Japan rocked the photographic community with the announcement that they were selling off their camera division to Cosmo Digital Imaging. While Cosmo has announced it will continue producing cameras, photographers are waiting to see how this plays out.

So what about medium format camera backs, such as Leaf, Phase One, Imacon / Hasselblad and Sinar Bron? These digital backs can now produce files up to 39 mega pixels, but is a 16 mega pixel file from a Leaf or Phase One better than a 16 mega pixel file from a Canon 1 DS Mark II, the king of DSLRs? The short answer is yes, the medium format backs will produce a better file for reproduction.

The first reason is dynamic range. The ability of a digital camera to capture a high contrast scene with very bright highlights and dark shadows is expressed in dynamic range f-stops. When presented with a high contrast scene, such as a dark skinned person against a white building, a camera with a lower dynamic range will either blow out the highlights or create noise and lack detail in the shadows. Most of the Nikons and Canons have a dynamic range of 6 f-stops, while the major producers of medium format digital backs have a dynamic range of 12 f-stops. While a good photographer works to reduce contrast in a scene by softening shadows with reflectors and fill flash, the camera with the wider dynamic range will still produce a better picture with more detail for reproduction.

The second reason is related to the first. DSLRs such as Canon or Nikon capture files in 8 or 12 bit format (8-bit for JPEG, 12-bit for RAW), but the medium format backs capture 16-bit files. This means that the 16-bit files will have over 65,536 color values per RGB channel instead of only 256, and that the 16-bit file gives us over 281 trillion possible colors. How will that help a graphic designer, seeing that printed CMYK files are 8-bit files?

As a graphic designer edits an image file, data is lost. For example, as an image is brightened, you can see gaps in the Photoshop historigram. Photoshop works hard to fill in these gaps, but data is lost, and the image quality goes down. If a designer works with a 16-bit image, edits are much less damaging, as there is much more data to work with before there is a visible loss in image quality. When the file is converted to 8-bit for printing, it is a better quality file. See http://www.earthboundlight.com/phototips/8bit-versus-16bit-difference.html for more info on 16-bit files. If you plan to make extensive edits to an image, ask your photographer for a 16-bit version of the file.

Art Directors working with studio photographers have become spoiled by medium format digital back's ability to be cabled to a computer. The instant feedback of seeing the image appear on screen moments after the shot is taken allows for changes to be made quickly, and the shot finalized with confidence. The small size of a Polaroid left many decisions to guesswork, but with a cabled back the Art Director knows the shot is in the bag. Although several high end DSLR cameras allow them to be cabled to a computer, the software does not work as well, and the result is less reliable.

Finally, file size is of primary importance for some projects, such as posters, outdoor signs, the sides of trucks. Canon's 1DS Mark II DSLR produces 16.7 mega pixels, or about a 50 megabyte 8-bit RGB file, the highest file size for DSLRs. Phase One's P45 digital back produces a 39 mega pixel file, a 112.2 megabyte 8-bit RGB TIFF file, or a 224.5 16-bit file.

This month it was my privilege to test several of the best medium format digital backs, and compare their quality against each other and my beloved Canon 5D. I have leased a Phase One P20 16 mega pixel back on a Mamiya 645 AFD body for two years, and now own a Phase One P45+. I tested the Leaf Aptus 75, a 33 mega pixel back side by side with a Phase One P45, a 39 mega pixel back on a Hasselblad H2 camera body. I also tested a Phase One P45 back on my Mamiya 645 ADF camera. I tried to create lighting that was very high contrast that would test the limits of the various image sensor's dynamic range. Part of the test was to try see at what point the highlights would blow out. You can see the result on this page.

Both the Leaf and the Phase One files show more dynamic range, more fine details and richer color than the Canon files. I prefer the color and details of the Phase One files over the Leaf files. Does this mean that I will be abandoning my Canon cameras and just shooting with medium format? No way! Much of my work is on location, and requires a lot of creativity. The Canon system is small, flexible, and allows me to try unusual angles and experiment with unusual cropping. Both Hasselblad and Mamiya only offer one medium range zoom lens, and no wide angle zooms, while my Canon system has quality zoom lenses in every focal length possible. I will always shoot with my Canon system because it fits my style, and when I need a larger file size or I am shooting a high contrast scene I will shoot with my Phase One 39 mega pixel P45+.

For additional information on Davis Photographic, see http://www.DavisPhotographic.com http://www.Photographer-Corporate.com or http://www.PhotographerFood.com

For additional information on the systems mentioned here, see http://www.phaseone.com http://www.leaf-photography.com/ http://www.hasselblad.com/ http://www.mamiya.com/ http://www.canon.com/