文章很长，由于不懂许多摄影的专业术语，加之本人的英文水平有限，希望有兴趣的大侠翻一下。
有的问题是明确的：1、N1的对角速度与N和C比还有一定差距；2、5个对角点中，中间一点为十字的，其他为线型，但对水平或垂直的线条的敏感性相同。不是西老文章中猜测的全部是线形。3、快门释放延时1/10秒；其他如曝光的准确性等，均比较优秀。

Contax N1  TEST  REPORTS  
FEATURES AT A GLANCE
Camera: Contax N1 35mm autofocus single-lens reflex with Contax N bayonet lens mount. Suggested list price: $1600. Street price: $1,299. Lenses used: 24-85mm f3.5-4.5 T* Zeiss Vario-Sonnar ($1,200; street) and 70-300mm f/4-5.6 T* Zeiss Vario-Sonnar ($1,500).
Focusing and viewing: AF and manual focus. Five CCDsensor AF system with central cross-field. Outer line sensors on diagonals, are equally sensitive to horizontal and/or vertical subject lines. Focus-priority in single-frame AF; release-priority in continuous AF. Focus button toggles to AF in manual-focus mode, and locks focus in AF mode. Active AF sensor is automatically or manually selectable with thumb-operated joy stick mechanism. AF sensors may be selected individually or grouped to weight AF to top, bottom, left or right of viewfinder screen. AF sensitivity range: EV 0-18. Autofocus bracketing; patterned AF-assist beam to 16.4 ft. Focus confirmation in manual focus mode. Multi-mode depth-of-field preview. Fixed eye-level pentaprism; user-interchangeable focusing screens; eyepiece shutter. Finder shows 89.6% of on-film image area or 0.71X magnification. Adjustable diopter eyepiece.
Shutter and exposure control: Electronically controlled, vertical-travel multiblade focal-plane shutter with speeds 32-1/8000 sec plus Bulb. Shiftable program, aperture and shutter-priority, plus metered manual. Exposure compensation to ±3 EV in 1/2 or 1/3 step increments. AE bracketing to ±1 EV in 1/3, 1/2 and 1-step increments. Multiple exposures; AE lock; 2- or 10-sec cancelable self-timer with LED countdown; optional wired, electronic remote release.
Metering and range: Silicon photo cell reads 5-segment evaluative, center-weighted or 3-mm spot patterns. Range: EV 0-21 for evaluative and centerweighted readings; EV 3-21 for the spotmetering range (ISO 100; f/1.4 lens).
Loading and winding: Autoloading and advance to 3.5 fps, with auto- or manually-engaged motorized rewind with normal or silent modes; mid-roll rewind.
Flash synchronization: Five pin hotshoe for Contax TLA (or compatible) flash units. Provides full TTL dedication, including automatic fill flash, second-curtain sync and more. Flash sync up to 1/250 sec.
Power source: One 6-volt 2CR5 lithium cell.

TEST REPORTS  01
Have Carl Zeiss lenses and an innovative AF system turned Contax s new autofocusing 35mm SLR into a star?
Quick Guide to What s Important
First 35mm SLR to accept Carl Zeiss autofocusing lenses
Five-point AF system with center cross sensor and outer sensors on diagonal lines
Active AF sensor manually selectable with unique joy stick control
First AF SLR to offer autofocus bracketing
Twenty Custom Functions
Body made of new crack-resistant carbon-fiber reinforced nylon
Unique optional remote LCD viewfinder
Accepts Contax 645 AF lenses with optional adapter
Not compatible with Carl Zeiss MM-mount manual focus lenses  

The year was 1982, and the place was the massive international photo trade show held biannually in Cologne, Germany. Behind closed doors, the editors of this magazine were treated to a glimpse of the future: a prototype 35mm SLR that, with a small, high-torque, relatively quiet motor in its housing, could automatically focus the image. Clearly, a revolution was in the wings. The camera, dubbed the "137 AF," predated the first mass-produced autofocus SLRs by three years and wasn t made by Minolta, Canon, or Nikon, the three camera makers that have since made major reputations with autofocus pro-level 35mm SLRs. That first, fully operational 35mm autofocus SLR was a Contax. Now, nearly 20 years later, Contax is finally bringing a 35mm auto-focus SLR and lenses to market. Why the delay, and was the Contax N1 worth the wait? Let s see.

There s a two-word answer to the first question: Carl Zeiss. The great German optics maker, and traditional Contax lens supplier, caused the delay. The problem? The relatively loose tolerances that Zeiss felt was needed by other manufacturers for such an autofocus system would lack the precision required to carry the Zeiss name. Not to be left out of the autofocus party, Contax, in a bout of engineering brilliance, went to the unusual extreme of designing the Contax AX, a 35mm SLR that autofocuses using manual-focus Zeiss lenses. How? By shifting the film plane!
In the ensuing years, internal-focusing lens designs, higher-torque, lens-housed focusing motors, and space-age lubricants have all contributed to making Zeiss precision and autofocus lenses compatible. Seven AF lenses for the Contax 645 AF were introduced in 1999 and produced highly successful test bench results. Now Carl Zeiss has brought forth four 35mm AF lenses in a unique N mount, and Kyocera, maker of the Contax, after 20 years of champing at the bit, has finally unveiled the first true successor to the 137 AF, the Contax N1. Yes, we had seen and handled a preproduction N1 and reported on it, but now we have a pristine, full-production camera ready for testing.

Removing the N1 from its box, and bayoneting on the Zeiss 24-85mm f/3.5-4.5 Vario Sonnar (the 50mm f/1.4 Planar wasn t available for testing), our first impression was that Contax had apparently set out to make the best 35mm AF SLR possible—regardless of size and weight. The N1 (like its Contax stable mates, the AX and RTS III) is a brute. Heavier than even the Contax 645 AF (28 vs. 22 ounces, body only), the N1 has an aluminum-alloy mirror box and a carbon fiber-impregnated nylon body that, unlike most polycarbonate bodies, is claimed to be unbreakable if crushed, for example, by a 350-pound NFL lineman. (Ordinary fiberglass-impregnated polycarbonate bodies have been known to crack and break in similar circumstances.) The N1 stands 4 5/8 inches high, easily among the tallest AF SLRs without a motordrive booster. With our test zoom attached, the package comes to 3 1/8 pounds, comparable to some 645 medium-format rigs. Your hands tell you that physically the N1 will probably last a lifetime.

TEST REPORTS 02

AF Assist beam: It tested far better than Contax specs indicate. Good to more than 30 feet. Operates only when central or all five AF targets are selected.  
It s a beautiful thing. With smooth matte surfaces, clean muscular lines, and exquisitely formed (and joined) parts, the N1 exemplifies the highest design and manufacturing standards. Despite its heft, the camera sits comfortably in the hands, with excellent balance, a well-formed grip, and convenient back-side thumb groove. This groove, together with the camera s wall-to-wall external rubber coating, provides enough purchase that we could confidently tote the N1 with one hand, without fear of its slipping from our grasp. Dust- and moisture-resistant O-rings and gaskets surround its dials, levers, and buttons.
The finder image is of average brightness, but pleasingly contrasty—due, in part, to the solid glass pentaprism whose mirrored surfaces are said to be specially manufactured to reduce flare. Finder readouts line the bottom of the viewing field; they are bright and easily legible. Commendably, Contax uses separate analog metering scales in 1/3- and 1/2-stop increments, depending on how you ve set Custom Functions—much preferable to systems that attempt to display 1/3-stop increments on scales designed for 1/2 stops.

The N1 s overall control layout is uncluttered, logical, and similar to that of the RTS III, with AE modes and shutter speeds set on the top left (a lever and dial, respectively). Also RTS III-like in positioning: the exposure compensation (±2 stops in 1/2 or 1/3 EV increments), autobracketing (±1/3, 1/2, or 1 stop), drive controls, and the system on/off, which is concentric with the large, contoured shutter-release button. The postage-stamp-sized, top-deck LCD panel is small by today s standards, but over twice the size of the Contax AX or RTS III panels. Its readouts (backlit for an ample 20 seconds, upon demand) are legible and logically presented.

The N1 s shutter is pleasingly quiet, and the reflex mirror s action produces a muffled, satisfying "thunk." The ultrasonic motors in the Zeiss lenses purr softly. (There are no other words for it.) The N1 s film advance is somewhat loud, producing a short, high-pitched whine between frames that is especially shrill during film take-up. The two rewind modes, normal and slow (silent), are also somewhat loud by today s standards, though not objectionably so. With auto take-up, advance, and multimode rewind, the film advance system provides a top framing rate of 3.5 fps, with no special booster required. Not bad.

Before loading the camera with film, we explored the AF system and were impressed with the quiet assurance with which it snaps the viewfinder into sharp focus. The autofocus system is actually quite innovative, much more so than Contax s promotional literature indicates. As with many AF systems today, it starts with ultrasonic AF motors located in each lens, that are driven by a CCD-based, phase-detection system in the camera body. Only the 100mm f/2.8 Zeiss Makro-Planar uses an older, non-ultrasonic (and presumably louder) motor.
TEST  REPORTS 03

The gang s all here: The first four Carl Zeiss T* AF lenses ever for a 35mm camera system include the (mounted) 24-85mm f/3.5-4.5 Vario-Sonnar, and (clockwise from foreground) the 50mm f/1.4 Planar, 100mm f/2.8 Makro-Planar, and the 70-300mm f/4-5.6 Vario-Sonnar. Also shown here, Contax s still-not-available remote LCD viewfinder. It displays the finder image with no need for you to peer through the finder eyepiece. Nice!  
The N1 autofocus system uses a central cross-shaped sensor flanked by four outer single-line sensors that are positioned to form the four corners of an almost square shape (and not a more conventional oval or rectangle). The sensors operate with lenses having a maximum aperture of f/5.6 or greater.
The N1 s design positions the four outer single-line sensors diagonally. Thus AF sensitivity is equally suited to snagging horizontal and/or vertical lines. More and more 35mm AF SLR makers are coming to this solution. Sitting at our desks and scanning the office, as we often do with a new camera, we found that the N1 s outer linear sensors did lock onto both horizontal and vertical low-contrast lines that typically defeat the single-line sensors of other AF SLRs.

Kudos to Contax for centralizing all AF controls on the camera back within convenient striking distance of the user s right thumb. One such control is the unique focus frame selector—a stubby joystick surrounded by a concentric lever. Nudging the joystick moves AF sensitivity around the four corners of the AF box. For the center spot, you press the joystick directly in. We judge it to be among the most convenient methods for manually selecting an AF point.

Another unique N1 AF option: The ability to weight AF sensitivity to the left, right, top, or bottom of the frame by linking the appropriate sensors. You shift the weighting by tweaking the collar switch that s concentric to the joystick. This multipurpose lever also engages the five-target autoselect mode in which the camera picks an AF sensor, usually the sensor corresponding to whatever subject element is closest. Finally, the lever can also be used to lock in the current AF sensor selection.

Yet another camera-back AF control is the thumb-operated "focus button" and surrounding AF mode selector switch. The switch sets each of the available focusing options—single, continuous, manual focus, and the N1 s unique focus-bracketing mode. You use the central focus button to quickly shift from manual to autofocus, a useful and, we think, unique feature. In the AF mode, the focus button serves as a convenient focus lock.

The N1 provides a choice between knobs or dials. You can, for example, set shutter speeds by turning the large, knurled top-side shutter-speed dial. The dial is conventionally shaped, but not conventionally positioned. Unlike similar shutter-speed knobs on other brands, it s on the top of the camera, similarly positioned to those on the Contax RTS III and other Contax SLRs. Some of our testers have questioned the knob s position, because changing shutter speeds forces you to remove your left hand from a supporting position below camera and lens. Contax, however, provides a solution with the N1: You can transfer shutter speed selection to the right-side command dial, which is immediately beside the shutter release under your right forefinger. With the N1 so configured, you can easily change shutter speeds while your left hand continues to support the camera and lens with the camera at eye level. The same, by the way, is true for exposure compensation. You can compensate exposure with the large, top-side, knurled knob or by a quick forefinger flick of the command dial. Your choice.
TEST REPORTS  04
Multiple exposures, too. You set up to nine multiple exposures by simultaneously pressing the Drive and Light buttons.
The N1 s AE system has the standard meter patterns, exposure modes, and overrides. The five zones of the segmented meter correspond in position to the five AF sensors, but, somewhat surprisingly, N1 metering operates independently of the AF system. Contax commendably locates the exposure overrides (i.e. exposure compensation and bracketing) around the same dial, although an unusual amount of top-deck real estate seems to be dedicated to exposure compensation, with its large, clearly labeled knob. A maximum bracket of a single stop (up or down) is a bit stingy compared to most advanced 35mm SLRs today, which provide bracketing of two or three stops (in both directions). Otherwise, AE controls are easily engaged, well marked, and logically positioned around the camera body. Several, like the exposure check button, are unique to Contax; they re described in more detail below.
For the the results of our field testing, let s start, uncharacteristically, with the N1 optical system. Traditionally, one of the compelling reasons to opt into the Contax system has been its famously sharp Carl Zeiss T* lenses. Four Carl Zeiss AF lenses were introduced with the N1: two Vario-Sonnars, the 24-85mm f/3.5-4.5 and 70-300mm f/4-5.6, a 50mm f/1.4 Planar, and a 100mm f/2.8 Makro-Planar. Like the N1 itself, theses lenses are large. At almost 21 ounces, for example, the 24-85mm weighs a third more than a typical f/3.5-4.5 zoom in this focal-length range.

Only the two zooms were available at test time. The lenses are in short supply, according to Contax, because Zeiss production tolerances are unusually high: About seven out of ten AF lenses fail initial quality-control tests and are returned to the production line. To expand optical options, at least for Contax 645 users, Contax offers the NAM-1 lensmount adapter. With it, you can mount any of the seven Zeiss AF T* lenses made for the Contax 645—fully coupled with AF and AE systems. We tried the 645 s 80mm f/2 Planar on the N1 and found it surprisingly convenient, satisfactorily sharp, and only a smidgen larger than the 35mm normal lens! (Our hope? That Zeiss could also design an N1 adapter that will accept the MM-mount manual focus lenses, even without meter coupling.)

Top-notch AF
The lenses  focusing motors delivered excellent AF speeds. The N1 had no trouble swiftly locking onto typical subjects, even in low light. The N1 s central cross sensor performed particularly well. It locked onto a difficult, low-contrast test target in dim light. More than half the AF systems we ve examined failed this test (as did The N1 s outer sensors).

The N1 s patterned, conventionally positioned red-light focus-assist beam, which Contax claims works to almost 17 feet, operated for us in a totally dark room at distances upward of 30 feet.

We heartily endorse the joystick solution for selecting AF points, and we hope that other camera makers pick up the idea. A nudge is all it takes to circumnavigate the five AF hot spots. We also laud the focus button. It falls directly under your right thumb and provides the ability to toggle on the fly between manual and autofocus. It s particularly useful in situations where objects move between you and a more distant subject. Problematic, however, was the collar switch around the joystick. We found the switch turned too easily to its locking position. More than once during our tests we pushed fruitlessly on the AF joystick, trying to change AF sensitivity, only to discover that we had inadvertently locked in an AF sensor.

The N1 s AF system performed admirably with moving subjects, following swiftly gliding ice-skaters around a rink with a 90 percent success rate, even on a heavily overcast day. As with most AF systems that use illuminated AF targets in the finder, the N1 s can be hard to see in bright light. We appreciated the Contax backstop: The active AF sensor is also indicated on the external LCD panel, where it s easily legible in bright or dim light.
TEST REPORTS 05
A handful! Although tank-like, the N1 is designed for gripability and balance. Important controls can be easily operated with the camera at eye level.
Promising in theory, but questionable in practice, the N1 s unique autofocus bracketing feature makes three pictures, bracketing focus around your subject. The first picture autofocuses the subject as precisely as possible. The second refocuses the subject at a slightly closer distance, but still within the depth-of-field zone. The third shot refocuses the subject at a distance slightly farther than the optimum focus point. In each case, the subject should be sharp. (With Custom Function  8, you can double the shift in focus.) To prove the usefulness of the feature, we set up multiple test situations—alas, to little or no avail. Shooting at a variety of apertures, with fore-, middle-, and background objects close together or far apart, where a difference could be perceived, it was deemed inconsequential. Our guess? This feature is a hand-holding gesture for users who require absolute sharpness—unnecessary in our estimation, because you would be hard pressed to find a soft subject among our dozens of test rolls.

On-target exposure
The N1 exposure system produced an overwhelmingly large percentage of correctly exposed images on slide and print film. We feel, however, that linking metering and the AF system would be an improvement. The camera s ability to weight AF sensitivity to the top, bottom, left, or right of the screen is, in certain situations, very useful. It would be even more so, if metering could follow suit.
We liked Contax s unique exposure check button on the right front of the camera body. It let us take meter readings independently of the shutter release and was especially useful for making meter readings with gloved fingers. Even better, the exposure check also doubles as a backup AE lock (via Custom Function  3). We found it much more easily operable with the camera at eye level than the N1 s standard AE lock, a rather stiff collar switch surrounding the shutter release. Through Custom Function  2, the AE lock can also be engaged with a half-press of the shutter release.

Internal and external LCD data readouts were clear and helpful. The analog exposure scale in the viewfinder displays different info, depending on the meter mode. At first it can be confusing, but once you know what you re looking at, the applications are obvious. In the evaluative meter mode, for example, the sliding scale displays the difference between the evaluative reading and a centerweighted reading. If the two readings diverge, it s an excellent signal that spot metering or exposure bracketing may be required. Other scale readouts include the difference between exposure compensated and recommended exposures, plus the difference between manually set and meter-recommended exposures.

Flash pictures were also excellent from our test unit, the fully dedicated, five-pin Contax TLA 360, which, among other abilities, swivels, tilts, and displays flash-exposure confirmation in the finder. The N1 s centerweighted TTL flash metering cell performed well with all subjects, except for those located toward the edge of the frame. Here, the pictures were overexposed (relative to a competitor s 35mm flash system) in portraits made at night against a dark background. However, daytime fill-flash exposures made in very difficult, strong backlit situations at the N1 s speedy 1/250 top sync speed were dead-on accurate.

Closing thoughts
What photographer will be most happy with the Contax N1? For starters, anyone who demands the absolute peak of image sharpness. Our two test zooms produced impeccably sharp test slides. Also, the gadget-oriented will probably crave Contax s unique FE-LCD remote viewfinder ($675, list). Unavailable for our test, it s a 330,000-pixel CMOS sensor that reads the viewfinder image and displays it remotely on a 1.5-inch LCD screen. This inventive device lets you see your image without peering through the finder. Moreover, its output reflects exposure adjustments made via exposure compensation and the AE lock. For black-and-white shooters, its display can also be switched between color and monochrome. Cool!

So was the Contax N1 worth the eighteen-year wait? For the strong of wrist and deep of pocket, the answer is a resounding yes! Stay tuned for, by the way, for the as-yet-unnamed digital Contax SLR, a rumored 6 Megapixel model that will share body styling, lenses and accessories with the N1.

TEST RESULTS FROM OUR LAB

AF Assist beam: It tested far better than Contax specs indicate. Good to more than 30 feet. Operates only when central or all five AF targets are selected.  

Viewfinder: Focusing screen was of average brightness, but very contrasty. Viewfinder magnification, listed at 0.73X, was tested at 0.71X. Screen image show 89.6 percent of picture area, a very good result, but significantly below the claimed 95 percent. There was no detectable parallax error.

Autofocus and time lag: Autofocus speeds (tested without AF assist light) from EV 12 to EV 5 were clocked at approximately 2/3 to almost 3/4 sec, an average-to-above average performance. From EV 4 to EV 1, AF time measured nearly 3/4 to 1 sec, in the good to very good range. Results were the same for high- and low-contrast test targets at all light levels except EV1 where AF speed measured 2 sec, about average. The AF assist light engages at EV 4 and lower light levels. Shutter lag time between pressing the release and the shutter opening was a very short 1/10 sec.

Shutter Speeds: All were extremely accurate. From 2 to 1/2000 sec, there were no errors detected. At 1/4000 and 1/8000 sec, we found less than 1/15 stop underexposure, an excellent performance.

Exposure accuracy: Since no segmented metering modes, including the Contax s 5-zone evaluative meter, are measurable with our laboratory equipment, exposure tests were limited to centerweighted and spot meter modes from EV 4 to EV 17.
In program, aperture- and shutter-priority AE modes, exposures were extremely accurate with overexposure within 1/10 stop. In the manual-exposure mode, exposures were very accurate, with 1/10 stop over/underexposure from EV4 to EV 7, and 1/4 stop overexposure from EV 8 to EV 17.

Sound test: Noise levels for both single frame and continuous advance modes were in the very quiet range (64.8 dB average; 84.9 dB peak). Rewinding ranged from slightly noisy (76.5 dB) to average (71.4 dB) for the normal and quiet rewind modes respectively. Lens focusing motors were too quiet for our instrument to measure.