Thursday, July 2, 2009

The Unfulfilled Promise of Medium Format Digital

The Unfulfilled Promise of Medium Format Digital


Russell Abraham

There are stereo speakers that cost $10,000 and there are ones that cost $500. The $10k speakers may sound better than the less expensive ones, but it is a very well trained ear that can hear the difference. After all, we are human beings and not dogs. Our hearing has very well defined parameters and most of us fall within them.

In the world of imaging and printing the limitations are even better defined. We truly live in a world of 300 dpi at eight-bit color. That is the universal print standard for almost every manufacturer of printing devices in the world, from your $100 desktop printer to a multimillion dollar Heidelberg four color offset press. Eight-bit color is 256 gray scale values for one shade of one color. That’s a lot of fine tuned definition. Your monitor at eight-bit color can theoretically reproduce 17 million colors and shades. The human eye tops out at around 7 million colors. So eight-bit color on your monitor has the power to render over twice what your eye can actually see.

When you open a raw file on your computer you will notice that your resolutions are most likely in the 300 dpi neighborhood. It is silly to say, create an image at 900 dpi, because there would be no way to reproduce it. So, in a sense, the mega-pixel wars being waged by high end digital back manufacturers are all being played out on the somewhat level playing field of 300 dpi. A 60 Megapixel image from Phase One’s latest and greatest back is just a bigger picture at 300 dpi. The 12 Megapixel image from your four year old DSLR has the same resolution as the 60 Megapixel back. It just maps out to a smaller image. I shoot architecture, and there is the occasional need for the ability to map out a large image for display. But most of the time my images end up as 5x7 or 8x10 prints in a brochure or RFP. Recently, ASMP put together an exhibit of architectural photography for a national show. There were sixty prints taken by some of the top photographers in the country using everything from relatively inexpensive DSLRs to mega-pixel backs on modified view cameras. All of the images were stunning and the only ones that looked a little shabby were the few that were shot with film. Interestingly, the spec for reproduction on these mural sized prints was 200 dpi!

All of the medium format digital backs are based on a CCD sensor manufactured by either Dalsa or Kodak. The technology was originally designed for space satellite recognizance. Most of the newer DSLR sensors are based on a CMOS technology. The CCD photosite devotes more surface area to collecting light and as a result, does a better job with shadows and the bottom end of the color space. The CMOS sensor is a faster, less noisy, less energy consuming chip. ISOs on CCD chips top out at 800 while the latest CMOS sensors can capture images at an astonishing 6400 ISO. In just the past few years manufacturers of both sensor types have significantly improved performance and image quality dealing with many of the shortfalls of each system. Color quality has improved on CMOS chips and noise has been reduced on CCD chips.

I have done side by side tests of most of these systems with some surprising conclusions. The Canon 5D produced images that were as sharp or sharper than either the Hasselblad or Leaf/Mamiya systems boasting approximately3x the image size. I have taken small cuts of each of these images and placed them here so you can see some of the differences.

Click on any of the images below to see them in full high resolution

Most DSLRs capture at 12 bit color. The medium format sensors capture at 16 bit color. That means each pixel has 62,000 shades of gray from which to choose. This creates the theoretically possibility that your image on the screen can have billions of colors. Remember, humans can only SEE seven million and the display card on your computer can only reproduce 17 million. For all but the most strange applications, 16 bit color is the Red Herring of digital imaging simply because it is a standard that cannot be seen or reproduced.

For a working pro who has spent most of his professional life behind a view camera, I regret the fact that most of the medium format digital back manufacturers have not addressed the most basic issue in any camera design, namely making their products easy to use. Here is a short list of obvious failings that may very soon be the death knell for most of these folks.

1. Auto focus. Yes I realize that you cannot build an autofocus system for a back that is designed to fit onto a variety of cameras, but you could simply develop a software algorithm that could tell you if you were in focus. The technology is based on measuring contrast in the image and has been around for twenty years. Why doesn’t Phase or Leaf just buy it and build it into their backs?

2. EVF concept. This is important and it seems like it has just shot over these guys’ heads. You have to be able to see what you have before you click the shutter and an electronic viewfinder is the way to go. Even high end DSLRs are using them for live view. A small eight inch laptop could do this job handily using blue tooth technology. Here again, this is off the shelf stuff and would make these devices much easier to use.

3. AWB is a useful tool and sometimes a lifesaver, yet no digital back has the option.

4. Proprietary RAW file formats. Almost every manufacturer commits this sin, but the digital back folks would do themselves a huge favor and get out of the software business and leave that to the true imaging software heroes: Adobe. Adobe Camera Raw just beats the pants off any other imaging processing software out there and supports what should be a universal format, DNG. Thirty years from now, when Canon is on its Mark 17 and Canon RAW is CR-10, DNG will still open up those files. Every digital photographer on the planet uses either Photoshop or Lightroom and to pretend Adobe doesn’t exist is just silly.

5. Bigger sensors are overkill. Stop making bigger sensors and start making smarter ones. I cannot remember a time when the makers of photo gear were so out of touch with the needs and budgets of their customers. Most of us have to struggle for every dollar we earn in this challenging market and we need tools that are simple to use, work flawlessly and don’t cost us a year’s tuition at an Ivy League college.

I think it’s important to understand clients hire you for your vision and not your hardware. Since I switched to digital about five years ago, I think I have been asked only once or twice what camera I used. Staying abreast of changing technologies is important, but it is all too easy to get sucked up into a Mega Pixel numbers game that can ultimately be a fool’s errand.

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