Cambo Wide RS Anniversary fitted with a 28mm XL Schneider Super-Digitar lens.
The Wide RS Anniversary Edition is a limited edition of the Cambo RS Wide, a specialised "pancake" shift camera for use with medium format digital backs and extreme wide-angle lenses, which is perfectly adapted for use in architecture and landscape work, and is particularly useful for interiors, thanks to its relatively diminutive size.
Cambo BV, which was founded in The Netherlands in 1946, has the distinction of being the first studio camera manufacturer to produce an all-metal large format model. Only 65 certified and numbered cameras will be made. The camera sits at the top of the Cambo's digital range and offers all the convenience and ergonomic sophistication you would expect from such a rare but practical piece of kit.
Each anniversary kit, priced £14,955, includes a Wide RS camera body in either black or titanium finish, equipped with handcrafted ergonomic wooden handgrips. Two new lenses are included to complement the camera; the Schneider Super-Digitar 28XL and the Apo-Digitar 43XL. The latter is mounted in a tilt/swing lens panel, and both lenses are finished to match the chosen body colour.
The need to locate such short focal length lenses very close to the sensor - plus the high degree of precision required to ensure such lenses remain parallel to the sensor - dictates a rigid metal construction, a form now commonly known as a pancake camera. Just like rivals made by Alpa, Arca, Silvestri and Sinar, the Cambo relies heavily upon precision helical lens mounts to achieve accurate focus using an engraved distance scale. These lens mounts are matched to an individual lens at the Cambo factory to give accurate focus at infinity. Schneider Apo-Digitar and Rodenstock Digaron S & W lenses from 23mm up to about 120mm can be supplied and factory mounted.
Cambo also offers a range of extremely clever wide tilt/swing lens panels that provide up to ±5º tilt in two planes actuated by two knobs. These achieve precise focus at the sensor on subjects with challenging planes of focus that run from front to back or side to side. A judicious combination of tilt and swing will allow adjustment across a diagonal plane of course.
A new vertical gearing system has been designed for the rear of the camera, incorporating spring tension to compensate for the additional weight of a digital back. These enlarged and very comfortable controls provide +15mm or -25mm of rise and fall and ±20mm of cross movements. The movements displace the digital back, not the lens, and are therefore ideal when shooting overlapping images to create a panorama - the lens' optical axis remains fixed, so images should fit without hesitation. Making a fully manual stitch in Photoshop is entirely possible, but obviously a lens with a sufficiently large field of view would be required for such work.
A ground glass/fresnel lens and digital back interface, supplied together with the new Cambo RS Loupe kit, complete the Anniversary kit. The RS Loupe is a 3× Schneider optical loupe mounted on a magnetic plate that means it can be slid about on the back of the rear screen to check accurate focus even into the corners. This is probably the best single eyepiece loupe I have seen. Binocular hoods are even nicer, though much bulkier and generally more expensive, but having used a 3× Schneider loupe over many years to look at the ground glass screen of my 6×9 monorail, as well as millions of 35mm Kodachrome slides, the value of a really good glass can hardly be overstated. The loupe is rendered almost redundant, though, by a supplementary optical frame finder with a mask to match the lens in use, plus a tape measure or informed guess plus a quick digital test frame. As my eyes age, focusing the widest lenses, even with this excellent loupe and even in good light, reminds me why I love DSLR autofocus so much.
In detail - This shot, using around 100 of rise, reveals the extremely high resolution possible with the Leaf Aptus 11 12R back coupled with the Schneider Apo-Digitar 43XL lens mounted on Cambo's 65th Anniversary camera. The three detail shots show off the best of this combination from a 240MB TIFF file. Illustrative images © Adam Woolfitt.
Cambo Digital Wide cameras can be fitted with adapter plates to mount Hasselblad V and H1, Leaf/Sinar, Contax or Phase One/Mamiya medium format digital backs as well as suitable rollfilm backs, making the Cambo system extremely versatile and easy to integrate with almost any photographer's legacy equipment.
The Anniversary edition provides a very handsome setup for architectural photographers, and is extremely easy to use. The quality of engineering, allied to a thoroughly considered design, makes it a pleasure to handle.
To complement this competent camera, I had the use of the Leaf Aptus 11 12R back, an 80-megapixel, 645-format unit that delivers a 240MB file (as an eight-bit TIFF) of 10,320×7752 pixels, which are just over five microns in size. The Dalsa-made sensor measures 53.7×40.3mm, which effectively covers 100 percent of a 6×4.5cm frame.
It's all too easy to drop expensive digital backs when mounting or remounting them so, to overcome such hazards, Leaf engineers have somehow found room to rotate the sensor within the casing of the Aptus back. A large and convenient thumb wheel on the left-hand side of the housing turns the sensor from vertical to horizontal, with a positive click stop at each limit. This is such a pleasure to use in any kind of shooting that it would be perverse not to buy this "R" version of the back, especially as it doesn't cost any more money.
To run the Aptus, I had the use of the very latest version of Leaf Capture, v11.5. More and more often, advances in digital image quality are achieved with sophisticated lens corrections applied to the raw files using dedicated software at the processing stage. The lens correction algorithms built into Adobe's Camera Raw can minimise or eliminate distortion and chromatic aberrations from a growing list of lenses from many manufacturers, and both Canon and Nikon provide corrections either in-camera, or in their proprietary software. Hasselblad's Phocus software will correct distortions, chromatic aberrations and vignetting with H-series lenses, and has proved especially valuable with the Hasselblad TS 1.5 Tilt and Shift adapter, where even the degree of rise, fall and tilt are factored into the processing mix using data fed from minute built-in sensors.
Calibration process - These three images show the degree of fall-off and colour bias inherent at the extremity of the image circle of the 28mm XL Schneider Super-Digitar at f/11. In the middle image, the calibration file created in Leaf Capture v11.5 is shown, and on the right the final image shows the corrected file after applying the calibration. In this instance no movements were used as the 28mm has very little surplus image circle when used with the 53.7x40.3mm sensor area of the Aptus 12R.
The sharp fall-off in illumination at the edge of the image field in extreme wide-angle lenses, and the acute angle at which the peripheral rays strike the pixels in the corners of the sensor, can generate very noticeable colour casts in raw files. Sensor manufacturers supplying medium format cameras address this problem by applying microlenses to the surface of the chip to help gather and direct the oblique light rays into the pixel wells, and digital back manufacturers combat it with software. An exception to this rule is found in DSLR cameras (medium format and 35mm) where an inviolable lens-flange-to-sensor distance must be maintained to accommodate a moving mirror. This problem is resolved with lenses of retro focus design. But few very wide-angle lenses for medium format capture with pancake cameras are of retro focus design and able to offer a flange-to-sensor distance greater than their nominal focal length.
The 23mm, 28mm, and 35mm Rodenstock HR Digaron series all do this. Even so, there is much work for the software to do to interpret the files correctly, and a starting point is a properly constructed calibration file. The process of building such calibration files involves making a series of exposures with the wide-angle lenses to be calibrated, using an opaque white Perspex filter over the front. This needs to be repeated for each significant variation in rise, fall or cross, and over a range of probable f-stops. From these strange-looking image files, a dedicated facility in the Leaf software allows you to create a look-up table for all likely variables. The resulting calibration files are then stored on the computer in the Leaf Capture folder, and can be invoked to batch process series of similar camera files. They can also be transferred to a CF card for use in the camera to correct images at the time of capture.
Interiors photographers will like the Cambo's relatively small size, along with the 28mm XL Schneider Super-Digitar wide-angle lens used here at f/11 with 00 of rise. The image was captured with a Leaf Aptus 11 12R back, and fall-off and colour banding were corrected with a matching calibration file during processing. Images © Adam Woolfitt.
Charles Woods, the sales manager of Cambo UK who is also a Leaf dealer, demonstrated to me that if the calibration files are scrupulously created, you will get perfect results, noting that the latest v11.5 Leaf Capture did a noticeably better job of this. Yair Shahar, European sales manager of Leaf, which is now owned by Phase One, pointed out that the latest version of Capture One Pro (v.6.2.1) offers a similar facility for building calibration adjustments for specific lenses, but I didn't find it quite as good. But many users will agree with me that C1 Pro offers a greatly improved workflow, especially as it opens Leaf.mos raw files nearly twice as fast as Leaf capture - 120s versus 72s on my Macbook Pro.
Both the Schneider lenses on test delivered frankly amazing levels of resolution across the field on the enormous 240MB eight-bit RGB TIFF files from the Leaf back. Central resolution was impeccable and both lenses benefited from only modest stopping down, with optimum results obtained between f/8 and f/11. Beyond that, depth of field improved of course, but resolution stayed the same or dropped minutely, perhaps due to the onset of diffraction. There was also some evidence that the colour-fringing issues on the Aptus back became more severe the smaller the f/stop.
The superb image quality obtained from the 80-megapixel back with standard lenses on a Phase/Mamiya camera proved beyond reproach in my review in BJP #7786. But the laborious process of calibrating the Aptus 12 files to overcome illumination problems peculiar to these very wide lenses makes me question whether a sensor with larger pixels - giving a lower pixel count and therefore lower resolution - would serve the architectural photographer better.
These sensor issues are completely separate from the Cambo Anniversary camera itself, which does exactly what it says on the tin, and does it very nicely. It is perfectly adapted for purpose and there is evidence of serious thought in the practical aspects of the design and implementation. The only practical difficulties I had were reaching around the enormous front element of the 28mm XL Schneider to set the aperture, speed or distance scales, and of course seeing the scales in the first place. At least the ever-practical Cambo engineers have made a tiny LED light that magnetically attaches to the metal body, allowing hard-pressed photographers to see the lens settings in the dark.
Cambo has clearly been listening to photographers' feedback. The sheer precision of the engineering and finish is a delight, and the restrained colour scheme looks positively chic. No doubt a few of the titanium-finish Anniversary sets may end up in glass trophy cabinets - and I can understand the impulse, but it would be a waste of a terrific piece of kit.
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