Mamiya 7

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July 1995

British Journal/Photography

On Test: Mamiya 7 The Lenses

Geoffrey Crawley

The new Mamiya 6x7 format camera boasts four lenses; Geoffrey Crawley puts them through their paces.

For the Mamiya 7 four lenses are available - 43, 65, 80 and 150mm, compared with the three for the 6MF - 50, 75, and 150. Again, 150mm is about as long as can be reasonably framed in a fixed magnification, here X0.57, direct vision viewfinder. The 43mm view angle exceeds that of the camera's finder and an accessory one fits in the camera shoe. The bright-line finder frames for the other lenses show ca 83% of the photographed area and compensate for parallax as the lens is focused.

The rectangular 6x7 frame makes for more comfortable viewing than a direct vision 6x6 one. Being on the left end of the camera, left-eyed users have no encounters with the film wind lever. In fact there is somewhat better support with it at the left eye since the length of the camera back is then pressed flat against the forehead. Fool- and reviewer-proof interlocks prevent lens interchange until the gate masking curtain has been drawn across and the film wound on. The tripod bush is 25mm to the left of the optical axis. This allows the camera to be fitted to a tripod head up to about 80mm across while leaving access to the curtain lever to change lenses.

But it inevitably means removing the camera from a tripod to reload film, since the pop-out lug for the take-up spool is clamped by the head. One can live with such quirks, especially as this is essentially an eye-level, hand-held camera. The lenses lock home in the bayonet fitting with zero play. You will not find any that do so more securely, especially as on the Mamiya 7, the lens box does not retract. You must align the white dots and give a short clockwise turn.

One query may be settled at the outset; you cannot swap lenses between 6MF and 7. They are incompatible, not so as to make things difficult, but because the back-focus is necessarily different. Their livery, like that of the camera body, is the same: handsome black anodizing with white inking of markings, and the foot scale is in yellow. Focusing movements are firm and precise. The maximum apertures, f/4 or 4.5, are not large but they keep down size and weight, and the quality of modern fast films means wider apertures will not usually be missed.

N43mm f/4.5L
This lens is the show-piece of the new camera. Its view angle is 92 degrees on the 6x7 diagonal, 78 degrees on the horizontal, which is often more to the point. Roughly equivalent to a 21mm lens on 35mm, it is a handsome chunk of glass weighing 390g.

Deeply recessing in the camera it extends only 44mm from the flange, 62mm with the hood. Using 10 elements in 6 groups, it has an essentially symmetrical construction. That bodes well, as usual, for good drawing maintained across the focusing range, here down to 1m. It also gives good shape retention in out of focus planes, optimizing field depth. Minimum aperture is f//22, reached in click whole stops.

It comes complete with an accessory-shoe fitting, direct viewfinder which has diopter correction. There is a bright-line frame with marks for infinity and one meter, and for the 35mm panorama format. A bubble spirit-level disc is visible below the frame, imaged from the actual one on top of the finder. The eyepiece has a soft rubber eyeshield, which spectacle wearers can fold back. On equipment of this quality a finder which tilts when set to the subject distance might have been useful but a different leveling device would be needed. Since one cannot expect perfect tight framing with a direct vision finder anyway, it's perhaps best as it is.

From its description, Mamiya is very proud of this lens, pointing to the design freedom given by the ability to recess it in a CRF body. The claims for good drawing and suppression of lateral color aberration were borne out on test. And it gave a sharp image across the frame at full aperture with high contrast. The part stop to f/5.6 crispens up, and by f/8 very fine detail is very well defined. As regards vignetting, also claimed to be reduced, the review sample showed an anomaly. The top left corner only showed fall off - maintained at all apertures - with or without lens hood. Only significant with less than full exposure, it could be due to off-centering or a shutter blade fault. In any event, it did not detract from the view that this is an outstanding state-of-the-art design.

N65mm f/4L
This is a "normal" wide-angle lens with a 69-degree diagonal, 56-degree horizontal view, roughly equivalent to a 32mm on 35mm. It recesses a little in the camera and extends 65mm from the flange; weight 380g. It has a capable hood with a window so as not to mask the viewfinder. It uses 9 elements in 5 groups in a basically symmetrical construction and minimum focus is again 1m.

On test, like its wider fellow, drawing was all but ruler straight with sharp high contrast coverage across the frame at full aperture f/4, and vignetting free. At f/5.6 very fine detail sharpened to become really crisp at f/8. One could hardly expect more.

F80mm f/4L
The standard lens of the Mamiya 7 gives a 58-degree diagonal, 47-degree horizontal view, equivalent roughly to a 39mm on 35mm. Taking the old criterion of the length of the format diagonal as the "normal" focal length would give 90mm as standard. (For 35mm it is 43mm.) So the lens is somewhat wide-angle, remembering that 80mm is a standard for 6x6, for which it is "normal" on the diagonal. Such theory aside, it works well on 6x7 and, more often than not one prefers a standard lens with a good view span rather than a narrower one.

At 290g it is the lightest of the four and extends only 56mm from the flange. Closest focus, again 1m. Developed from the 75mm f/3.5 for the 6MF, it uses 6 elements in 4 groups and is as near symmetrical as you will find.

The test pattern of the two wider lenses was broadly repeated once more with good drawing - a trace of barrel, top and bottom of the frame was negligible. Sharpness to the frame corners at full aperture f/4 was still better, as might be expected from the longer focal length. The crispening at f/5.6 was finally hardened at f/8. A worthy "standard" lens.

N150mm f/4.5L
This telephoto construction, related to the Sonnar type, uses 6 elements in 5 groups giving 34-degree diagonal, 26-degree horizontal view, as about a 71mm an 35mm. Focusing is to 1.8m and minimum aperture f/32. It extends 96mm from the flange and weights 520g. This is the classic head-and-shoulders portrait focal length for 6x6 and on 6x7 works equally well, giving a natural vertical portrait format. It balances well on the camera, and is convenient to use for candid work. After an SLR the comparatively small bright-line frame may be a little disturbing, but one soon learns to use it with confidence. The camera is light enough to be easy to use for the vertical format on a small tripod, remembering to attach it so the viewfinder eyepiece is at the top.

The lens uses ultra-low dispersion glass to minimize color aberrations and coma flare. On test, the f/4.5 full aperture performance was excellent with high contract and crisp detail across the frame. Stopping to f/5.6 and then f/8 brought in micro detail. The slight trace of pin-cushion at top and bottom of the frame would be insignificant in practice. Mamiya states it is, in effect, apochromatic; the focus shift for infra-red is, in fact, minimal. In short a superb lens.

Overall
The four lenses for the Mamiya 7 will not disappoint, they are obviously state-of-the-art designs and will fulfill the most exacting requirements. The crisp, impactful images are typical of the Japanese design philosophy which has won so many supporters round the world. In terms of span, the 65mm and 80mm are rather close together in view angle, considering the gap between 80mm and 150mm. A 110mm would fill this nicely and would be a very useful focal length.

The camera and lens array are very desirable professional tools. The CRF roll-film camera has its own protagonists, despite the charms of the WYSIWYG SLR. The Mamiya 7 should impress them, even if they do feel it and its lenses could be a little more price competitive. Products which promote larger formats are to be applauded. As to future developments: will we see interchangeable backs coming along to further encroach on SLR territory?

Is Bigger Better?
One of the attractions of going to a larger format, at least for the long-term 35mm user, is the thought of the frame being covered with the micro detail of which a good 35mm camera lens is capable. But it does not necessarily work that way. Leaving aside aspect ratios, if you scaled up a miniature camera lens to cover 6x7, increasing the focal length would magnify the residual aberrations in proportion. So no more information would be recorded. What you would gain, though, is the number of silver grains or dye corpuscles imaging a given area of the subject. That can mean smoother gradation of grey tones or color hues- enhanced overall image quality and a more professional result.

In practice, medium and large format lenses are not just scaled up but rethought and optimized for the image circle required. Nevertheless, say an 80mm lens for a 90mm diagonal cannot be expected to cover it with the micro detail of one for the 43mm diagonal of the 35mm frame. But the best will record substantially more detail, as well as giving the much better tonal and color subtlety already described. Such lenses are inevitably costly.

In the past, Japanese roll-film format lenses were variable in engineering quality and optical performance, very likely built to be price competitive. Over the past ten years the approach has substantially changed and, nowadays, designs are of a very high caliber- and so, necessarily, are the prices.

From the designers' point of view a coupled rangefinder camera lens brings a bonus to performance. Because of the mirror action an increasing constraint is introduced as the focal length of an SLR decreases. Its back focus must be longer than its focal length - just when design becomes more complex to give the wider view angle. In a CRF, short focal-length lenses can recess almost up to the film plane, freeing the designer from retro-focus problems. The Mamiya 7's 43mm lens rear glass is only 18mm from the film plane.

Reprinted with permission of the publisher.