Articles, Insights, and Tutorials
Kodak DCS Pro Back 645M
16 Megapixels of firepower on a medium format platform.
I had an opportunity to use a 16 Megapixel Kodak DCS Pro Back 645M for a couple of weeks and found the medium format Mamiya 645AFD based camera to be surprisingly easy to handle and operate.
The DCS Pro Back 645AFD's controls and digital system are consistent with a typical pro-style digital camera, so the learning curve is relatively simple.
Existing Kodak Pro camera users will feel right at home the instant they turn the camera on. The digital operating systems and menus are nearly identical to those found on the popular 300, 400, 500, 600, and 700 series digital SLR cameras.
The Digital Back
- Easy mount, easy dismount system, the same as any other interchangeable back on the Mamiya 645AFD camera... fast, simple, and rock solid.
- Fully self-contained: No external power cables or computer connections required.
- Operates just like a "regular" digital camera. Completely portable. Download images to your computer with a firewire cable, or pop the memory card out of the Pro Back and stick it in a card reader.
- Fixed studio rig option: Plug it into the included AC adapter, connect it to a computer, review & edit your images on the fly, and save your pictures directly to your hard drive. (That's not my cup of tea, so nothing more to be said about that here.)
- 16+ million pixel CCD image sensor, 36mm x 36mm square.
- Finished standard image size: 4072 x 4072 pixels, 19 megabytes raw in-camera, 48 megabytes saved as an 8 bit Tiff.
- Besides the standard 1:1 square aspect ratio, the Pro Back can be set up with an in-camera horizontal 5:4 or a vertical 4:5 capture crop. (I like the standard 1:1 aspect ratio because I can choose a crop afterwards, or leave the pictures square like the sample pictures shown below.)
- Adjustable sensitivity range of ISO 100 to ISO 400 in 1/3 stop increments, with little or no visible loss of image quality at the higher end ISO settings
- Instant image review available on the LCD screen, with optional histogram & highlights.
- Memory cards: Any Type I or II Compact Flash, including all sizes of the IBM Microdrive. And at around 19 megabytes per raw image, a one gigabyte IBM Microdrive will hold just over 50 pictures.
- Digital Back Battery System:
The digital back uses a separate single slide & snap-in rechargeable battery (shown at left), about half the size of a traditional Kodak DCS series battery like the DCS 520, 620, 620x, 560, 660, 720x, or 760 uses. The battery snaps and locks positively and securely in place on the bottom of the Pro Back.
- Bonus. As shown above, the big CCD sensor is "right there" when you take the Pro Back off the camera body. That means e-a-s-y cleaning when you get dust or dirt spots on it.
- Power consumption: Extremely mild... I regularly left the camera on for hours at a time, shooting up to a gigabyte of pictures on a Microdrive with repeated & regular LCD screen reviews, and never ran low on power. The Pro Back comes with a dual battery charger and one battery. (If you shoot more than 2 gigs of pictures at a time, it would be a good idea to buy a second or third battery.)
- High points: Ease of use, rich dynamic range, outstanding shadow details, excellent skin tone accuracy.
- Color quality:
Among the best I've ever seen except for one minor glitch. Foliage greens (grass, trees,etc.) straight out of the camera frequently have a slight blue-green look, but it's easily corrected with a one-step 20% to 40% reduction in the cyan field in the greens (only) under selective color adjustment (Adobe Photoshop).
The screenshot at right shows the simple correction procedure. Try 20% first, use up to 40% in extreme cases.
Again, skin tones (all kinds) are extremely accurate and lifelike.
The Camera Body
The Mamiya 645AFD camera body is a cross-platform system that is specifically engineered to include digital backs.
It's lightweight, comfortable to handle, and operates like a traditional 35mm SLR camera.
In addition to the Kodak Pro Back, the camera can be easily fitted with quick-change film magazines for 120, 220 or Polaroid film.
- The Mamiya 645AFD automatically transfers data between the camera body and the digital back via an internal coupler. (No extra wires, cables, or plugs are necessary.)
- Lenses: There are currently 10 autofocus lenses available:
- Bonus. All Mamiya autofocus lenses have a push-pull clutch system which allows an instant manual focus override by simply sliding the focus ring forward. This disengages the autofocus from the lens. No need to take your eye off the subject or change the camera body selector lever.
- Focus modes: (S)ingle autofocus, (C)ontinuous autofocus, (M)anual focus.
- The camera has a built-in infrared autofocus assist beam good for up to approximately 30 ft.
- Exposure Modes:
(P) Program AE Mode
Automatically determines optimal exposure settings, using pre-programmed aperture and shutter values to ensure exposure accuracy under ambient lighting. Digital dial-controlled program shift enables adjustment of shutter speeds and aperture in 1 EV steps from (P) mode.
(PH) favors faster shutter speeds and larger apertures. This is ideal for moving subjects or shallow depth-of-field used in many portraits.
(PL) favors slower shutter speeds and smaller apertures. This is ideal for landscape where control of depth-of-field is needed. These settings provide a versatile response to most shooting conditions. This mode is ideal for general photography without the need to make adjustments.
(Av) Aperture Priority
Adjust the aperture value with the digital dial to the appropriate setting, and the camera automatically adjusts shutter speed to match. Aperture values can be set in 1/2 stops.
(Tv) Shutter Speed
Priority AE Mode
Set the desired shutter speed via the digital dial and the camera automatically adjusts aperture value to match. Shutter values can be set in 1/2 steps.
(M) Manual Mode
Used to adjust settings based on readings from an exposure meter. The rear dial adjusts aperture value while shutter speed is set using the front dial. Both values can be set in 1/2 steps. The photographer can put half pressure on the shutter release to view the difference between set values and values metered by the camera and displayed in the viewfinder LCD. The difference indications disappear from the LCD panel when set values match metered values.
(X) Flash Synch Mode
Fixes shutter speed at the sync speed of 1/125 sec while allowing adjustment of the aperture setting. In this position, the exposure dial locks and cannot be rotated. Perfect for easy flash operation.
(T) Time Exposure Mode
Mechanically controlled mode for long exposures.
- Metering Modes:
(A) 5-Segment Evaluative Average Metering
Meters the average brightness of the entire image, with emphasis on the center of the screen. The four outer segments plus spot area are measured, the brightest of the outer four eliminated and the remaining three plus spot are averaged together for remarkable results is challenging lighting situations.
(S) Spot Metering
Meters reflected light on the image at a specific point, indicated by the circle at the center of the viewing screen. It is optimal for use with high contrast subjects and for measuring brightness at a specific area of the subject. The angle of acceptance changes according to the focal length of the lens attached.
(AUTO A-S) Variable
Automatically switches between 5-Segment Evaluative Average and Spot modes depending on the relative contrast within the overall image; it provides exposure settings suited to a wide range of subjects and lighting conditions.
- Maximum shutter speed: 1/4000.
- Shutter speed and aperture settings are adjusted using traditional style front and rear dials near the shutter button. Adjustments are easily made with the right forefinger and right thumb.
- All exposure and digital capture information is displayed in both the viewfinder and main LCD panel on the camera.
- Camera body batteries: The Mamiya camera body uses six AA batteries (alkaline, lithium, or rechargeable) in a built-in bottom-mounted removable carrier, similar to those found on many other brands of traditional film cameras.
- Exposure compensation is adjustable by a dial on the right side of the viewfinder in 1/3 stops with a range of plus or minus 3 EV.
- Other notable features: Adjustable viewfinder diopter (-2.5 to +0.5 standard, -5 to +3 with optional lenses), mirror-up lever, depth of field preview button, hot shoe on top of viewfinder for direct speedlight mounting, external PC synch socket to connect strobes or portable flash units, auto-bracketing function, self-timer, auxiliary port for electronic shutter release or other compatible devices.
Indoor available light snapshot taken under difficult mixed lighting conditions - overhead fluorescents & indirect sunlight.
Original image size reduced for web viewing.
Midday, strong overhead sunlight mixed with deep shadows. Great example of the dynamic range of the Pro Back 645M.
This is the first (ever) camera that got the orange color in her T-shirt "just right".
Original image size reduced for web viewing.
Late afternoon, strong shadows, direct sun against white fur.
Good job not blowing out the highlights, good shadow detail.
Original image size reduced for web viewing.
Kodak Photo Desk
Do your raw picture conversion with Kodak's Photo Desk software, then save it as a Tiff & send it to Adobe Photoshop. It's free, it's fast, it's clean, it's simple, and it's straightforward.
Does the Kodak Pro Back have a "multiplier factor"?
Yes. The Pro Back 645M has a larger available film capture area than the digital back's 36mm square sensor, so there is indeed a multiplier factor for Pro Back users compared to the angle of view they get using a traditional film back.
The multiplier factor compared to 645 film is approximately 1.5x with any given lens when the DCS Pro Back is installed. That's because a 645 film frame measures 56mm wide. Divide the film frame width by the digital sensor width and you'll have the multiplier factor. 56mm (645 film width) divided by 36mm (CCD sensor width) equals 1.5555 (I rounded it down to 1.5).
The Pro Back's sensor measures 36mm x 36mm (the same width as a 35mm film frame), therefore the captured picture has the same horizontal angle of view as a 35mm film camera. So if you think in terms of what you see using traditional 35mm film cameras and lenses, you'll feel right at home. And if you like the 35mm aspect ratio, it's really great, because you can crop the square picture horizontally or vertically to a traditional 35mm film 2:3 aspect ratio without having to turn the camera on its side.
Here's some confusing fun with multipliers...Comparing horizontal fields of view
- An 80mm lens on a Pro Back 645M gives you the same horizontal angle of view as an 80mm lens on a 35mm film camera. (1:1)
- An 80mm lens on a Pro Back 645M gives you the same horizontal angle of view as a 50mm lens on a 1.5x multiplier camera such as the Nikon D1X .
- An 80mm lens on a 645 film back gives you the same horizontal angle of view as a 50mm lens on a 35mm film camera (reverse multiplier because the medium format film back is larger.)
- A 120mm lens on a 645 film back gives you the same horizontal angle of view as a 50 mm lens on a 1.5x multiplier camera such as the Nikon D1X. (Double reverse multipliers.)
- Great camera system, an absolute pleasure to use.
- Outstanding picture quality, especially in print.
- Easy to learn and operate, not intimidating at all (as I originally feared).