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Cambo Wide DS

Working with the World's Most Expensive
Digital Point-&-Shoot

The Brick Press. Don Valley Brick Works. Toronto. November, 2005
Cambo Wide DS with Schneider Digital 35mm f/5.6 and Phase One P25 back

Obviously, when you read the description of the camera, lens and medium format back that was used to take the photograph above, and realize that the list price of this combination is about USD $35,000, you'll smirk at my description of it as a point-and-shoot. But, in some ways, and without any pejorative connotations attached to the words point-and-shoot, that's what this is.

In early November, 2005 Kevin Raber, Phase One's V.P. of Sales and Marketing for the USA, visited Toronto on business, and also attended my Brickworks Workshop. To spice things up he brought along his latest toy (err... tool), a Cambo Wide DS camera. On it was mounted a Schneider 35mm f/5.6 XL Digitar lens, and a Phase One P25 medium format back.

I've been using a Phase One P25 back on my Contax 645 system for well over a year now. But the idea of being able to mount that same back on a thin, light weight, and very flexible view camera was very appealing. After working for two days with Kevin's sample, I was hooked. I will be taking a Cambo in a Contax mount (his was in a Hasselblad back mount), on my Antarctic Expedition Workshop at the beginning of December.

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Construction

Since two days isn't nearly enough time to come to terms with as complex and fascinating an instrument as this, I will reserve my field-report till after my Antarctic trip. But this is a good opportunity to have a quick first-look at the Cambo, and explain what it is, what it does, and who it's for.

The Cambo is both simple and complex at the same time. In the simple side, it is a thin, beautifully machined metal plate that has a lens mount on one side and a medium format digital back mounting plate on the other. The lens mount is for the Schenider Digitar 5,6/24XL, Digitar 5,6/35XL, Digitar 5,6/47, and Digitar 4,5/55 Apo-Sironar in a helical focusing mounts. The back interface are for Hasselblad-V, Hasselblad H1, Contax 645 or Mamiya AFd digital backs.

The camera tested had the Schneider Digitar 35mm lens, and a Hasselblad V series Phase One P25 back. This lens is equivalent to about a 24mm lens on a full frame DSLR or 135 film. Nice and wide, but not so wide as to introduce too much perspective distortion. This lens has an image circle that allows for +/- 20mm of rise or fall, or shift adjustment, and this, coincidently, is the range of movements that the Wide DS provides.

There are two knobs on the front panel that allow for this through micrometer adjustment, with fine markings every mm, and numbers every 5 mm. There is also a locking knob on each control. These axis are also independent of each other. There are as well two imbedded bubble levels on the top panel as well as one on the front panel. There are "bull bars" to protect the lens from physical damage, and two top-mounted eyelets for a neck-strap.

The final and most obvious feature is a hefty rosewood handle slotted to accept a cable release. The picture is completed with a standard top-mounted accessory shoe, and at the bottom is a foot with a tripod mounting attachment – unfortunately not Arca Swiss / RRS standard sized. There is a 3/8th" thread hole for a tripod mount on the handle, for optional vertical mounting of the camera on a tripod. My impression though is that it's easier to simply flop the whole camera over on its side using a slotted ballhead. The whole thing is light enough that this isn't an issue, even using a small ballhead like the new and excellent RRS BH-40 LR , which I'm currently testing.

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Now What?

So you have this lovely and ultra-expensive device in hand. Now what? How do you use it, and what do you use it for?

As for the how, it's fairly straightforward. The lens is mounted in a Copal shutter and operates just like any view camera lens. There are levers for setting the aperture and cocking the shutter. A threaded lever accepting a cable release is mounted on the left side of the lens.

But, there's no rangefinder, and no ground glass. So how do you compose and focus? The answer is that since this body is designed for use with a digital back, you can simple take a frame, and then a second later look at the LCD screen on the back and see what you have.

Well, yes, that is possible, and it's what I did during my two days of intermittent testing, but frankly it's not the ideal solution, nor even very practical. I have ordered an optical viewfinder with a mask for the 35XL lens, and this will make setting up the shot and hand-holding much more practical and convenient.

As for focusing, unless you were to bother putting on a ground glass fitting (it's a time consuming affair to swap back and forth with the digital back ) you have to use guess-focusing. This really isn't an issue. For landscape work hand-held the camera will likely be at Infinity most of the time. When shooting on a tripod you'll want to stop the lens down to f/11 or f/16, and this will provide more than adequate depth of field for just about any situation that this camera is likely to be used for. Photographers have been working this way for more than a century with hand-held large format cameras.

And, when you're working on a tripod, the back's LCD screen will tell you just about everything that you need to know about composition, exposure and focus.

Of course exposure is completely manual, and therefore a decent hand-held light meter is important. But, on the first day of testing, both Kevin and I both neglected to bring a meter, and so we simply guessed at the proper exposure and then looked at the histogram, getting it spot on by the second frame. No biggy.

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Synchronization

Because the back and the lens (camera) have no way of know what the other is doing, there needs to be a means of having the two talk to each other. The reason for this is that the Phase One back spends most of its time in battery saving "sleep" mode, and needs to be woken up just prior to an exposure. On a normal medium format camera the interface electronics takes care of this as you press the shutter release. But with a system like the Cambo, and its dumb interface (meaning none), this is accomplished by a special cable which connects via the lens' flash sync PC contact and a socket on the digital back.

Press a small button on the cable and the back wakes up for 5 seconds. As long as you press the lens' cable release within those five seconds the back is awake, and the image is captured. Miss the timing and you need to re-cock the shutter, press the cable's button again, and then release the shutter in time.

This is an extra step, but since the operation of a camera like this is completely manual, with numerous steps that have to be taken before shooting in any event, I didn't find this to be any sort of impediment.

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Vignetting

All wide angle lenses vignette (dark corners) and the Digitar 35mm XL is no exception. There are two solutions. One is to fix it via software, such as Vignette from The Imaging Factory. This is the least expensive approach, but if possible it is preferable to use a center filter. These are expensive, but if you can afford it, and the two stops of light lost, it's likely the preferable approach.

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Optical Quality


Machinery. Don Valley Brick Works. Toronto. November, 2005
Cambo Wide DS with Schneider Digital 35mm f/5.6 and Phase One P25 back

A few dozen frames shot over two days is hardly sufficient to judge a fine lens. But, this is an extremely fine optic, designed specifically for medium and large format digital imaging. You can read more about these here, (though for some reason the 35mm lens isn't covered (it may be because it's a recent addition to the line)).

All I can say at this point is that I have been working with Zeiss lenses on my Contax with the Phase One P25 back, and have become quite familiar with their performance characteristics. I believed, until now, that this was about as good as optical quality gets. But after having shot with the 35XL Digitar and P25, I can tell you that the bar has now been raised to a whole other level. The detail and contrast that this lens produces when combined with a high resolution back like the Phase One P25 is nothing short of extraordinary. I can only imagine what the results will be when combined with the forthcoming Phase One P45 39 Megapixel back. (Of course I'll be testing and reporting on this combination as soon as available).

100% Enlargement (found above-center in the image)

On my screen, and in a large print, I can see the filament wires of the broken light bulb

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Lens Cast

As with all good things, as usual there is a dark underbelly, and in the case of wide angle lenses combined with camera movements and digital backs, that problem is lens cast.

Simply put, the issue is that the distance between the rear element of the lens and the back's sensor is minute. They are almost touching, unlike on an SLR camera body with a mirror housing. And in the case of the Phase One backs, there are no microlenses to compensate for the acute angle that the light rays take when hitting the edges of the frame, especially when the limits of the lens' imaging circle are used, with shifts beyond 10mm.

The solution that Phase One provides is a combination of a simple diffuser plastic card and software. You shoot calibration frames with your lens and back through the filter at each major shift distance, and then using the Phase One software save these as Lens Cast calibration files. The software then will semi-automatically apply this calibration to your raw files to compensate for green or magenta casts at the edges of the frame. Once the calibration files are created – about an hour's work –their application is simple thereafter. This is not dissimilar to creating noise profile frames when using some of the better noise reduction programs.

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Wide Aspect Ratio Shooting

One of the nice things about shooting with a view camera, or any camera or lens, for that matter, that has a shift capability, is that you can take one shot with the lens shifted right, and the other left, and then simply overlay them in Photoshop to get a perfect wide-aspect-ratio image. There is no need for stitching software, because the optical axis remains the same.

This works very well with the Cambo, but if you're using a Phase One back you'll need to apply appropriate Lens Cast correction as well as vignetting adjustment in software, if you didn't use a center filter. By the way, I have no idea if the software for any other digital backs provides lens cast correction in a manner similar to that provided by Phase One's Capture One software, You'll have to check with Leaf, or Imacon, or whomever else's back you might consider using to see what their solution to this might be.

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Availability

The Cambo Wide DS is available from pro dealers around the world. In the US it is sold by Calumet Photo, and in Canada by Vistek. Phase One currently (Q4, 2005) has an interesting bundle on it the US and Canada though its VARs, consisting of a Phase One back and a Cambo Wide DS system.

I will have a further report on this system in a couple of months, once I have greater experience with it in the field. In the meantime, professional photographers with a need for a light weight, superbly made, sometimes hand-holdable camera, with extensive rise / fall and shift capabilities, and an excellent wide angle lens, should have a close look at the Cambo Wide DS, especially if you already own a digital back. It's a professional architectural and landscape photographers delight.

You may find this PDF file, a review which appeared in PhotoTechniques magazine, to be of interest.


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Concepts: Camera, Large format, Single-lens reflex camera, Medium format, View camera, Hasselblad, Twin-lens reflex camera, Digital camera back

Entities: a Phase One, Schneider Digital, the Cambo, Toronto, Kevin, Kevin Raber, Arca Swiss, Zeiss, Leaf, Calumet Photo, USA, Canada, LCD screen, Photoshop, PDF file, Antarctic, dark corners, H1, Digitar 5,6/35XL, Digitar 4,5/55, Digitar 5,6/47

Tags: Phase One, camera, Phase One P25, Cambo Wide DS, digital backs, medium format, view camera, lens mount, cable release, wide angle, wide angle lenses, view camera lens, XL Digitar lens, Digitar 35mm lens, software, 35mm, Lens Cast correction, Lens Cast calibration, Phase One backs, Wide DS camera, Phase One software, fine lens, LCD screen, light weight, Contax, optical quality, flexible view camera, center filter, ground glass, format camera, format digital, large format, Capture One software, medium format camera, calibration files, SLR camera body, AFd digital backs, digitar 35mm xl, tripod mounting attachment, RRS BH-40 LR