Tom Shea 在Photo.net上发表的对G2的评论

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  灰色的边缘 (你说是为了和平，你才打仗) 2008-02-29 13:11:26

  我看到最后一句 G的28MM镜头也被认为强于徕卡的同档镜头。） 嘿嘿，看来买对了

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  灰色的边缘 (你说是为了和平，你才打仗) 2008-02-29 13:17:24

  两台相机的取景器是根本不同的。G2用一种可变焦距的望远式取景器，这种取景器会根据安装镜头的不同而自动改变取景器中景物的放大倍率。这与单反机上的取景器非常相似，都是因为镜头焦距的不同而改变了景物的放大倍率，镜头的焦距越长，景物就被放得越大。而在徕卡照相机上，取景器内景物的放大倍率是不变的 这点看上去很不好，会影响人取景的

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  BWV八核 (我是伪君子，伪读书人) 组长 楼主 2008-02-29 15:25:43

  Contax G2 by Tom Shea; created 1998 I will devote the first part of this review to considering the Contax G2 AF rangefinder system on its own merits. Then, I will take the more dangerous path and will compare it to Leica and SLR systems. Dimensions The G2 is a solid camera. It is 139 mm wide, 80 mm high and 45 mm deep. It weights 650 grams without batteries. It feels rather heavy and the controls are smooth and firm. It is a well built camera. The finish is excellent - unsurpassed in my experience. The lenses use a breech mount system and are a little fussy to mount. Lens Options Contax produces 16/8, 21/2.8, 28/2.8, 35/2.0, 45/2.0, and 90/2.8 lenses for the G2. With an adaptor, the camera can accept Contax/Yashica-mount SLR lenses. Focus The G2 uses an extended baselength autofocus rangefinder system. There are two modes. The first is an active focus system using an infrared light for close range focusing - particularly helpful in low light conditions. The second system, for subjects that are farther away, is a passive system, as found in most SLR's. With a close subject in adequate light, the active focus system acquired focus first and the passive system takes over to make the final precise focusing adjustment. There are several focusing modes available - single auto focus, continuous autofocus and manual focus. Any of these AF modes can be combined with either continuous or single frame film advance. For those who wish specific control of AF, the camera can be set so that it will autofocus when a button on the back of the camera is pushed. Exposure The G2 has a vertical metal focal plane shutter with speeds from 4 seconds to 1/4000 (extended from 16 through 1/6,000 in aperture priority mode), plus B. Flash sync is 1/200th. The TTL metering system has a range of 1-19 EV. There is also a external meter for the 16 mm lens (since this lens extends so far into the body that it blocks the internal meter). The metering pattern is center-weighted, reading off of a grey area on the shutter. Exposure can be set manually or by using aperture priority. Exposure compensation is set by a dial on the top of the camera, with a range of plus or minus two stops in 1/3 stop increments. An autobracketing control can be set for plus or minus half or whole stop bracketing. The camera uses a motor to advance the film with low and high speed options for the continuous advance rate. The fast rate is up to four frames per second. There is also a single frame mode, a self timer mode and multiple exposure mode. The shutter release is smooth and has a very good feel. Surrounding the release is a lever which acts as an on/off switch and an A/E lock. The camera can also be set so that A/E lock is achieved by partially pressing the shutter release. There are five custom functions, including film leader out or in upon rewind, manual focusing operation, bracketing order and A/E lock operation. Viewfinder The viewfinder is a zoom telescope. The picture frame area changes automatically depending on focal length of the lens and focusing distance. The viewfinder has information regarding the shutter speed, focus, exposure compensation and flash mark. The TTL flash system is normally good. There is a wide range of (expensive) Contax flash units available, including two small units (TLA 140 and 200) made specifically for the G2 which are quite simple to operate, though not as versatile as the larger units. In use How does it work? It can take very good photographs. It is easy to use. It is flexible for a rangefinder. It is noisy. This is the worst thing about the G2 in my opinion. The AF is very noisy - substantially noisier than any cheap point and shoot I have heard recently. Moreover, the lens returns to its base position after every shutter release, so that the lens refocuses from the beginning. However, autofocus is very fast, even compared with top AF SLRS. It is possible to lock focus, cutting the shutter lag to a miminal amount. Compared to ... Now, let me compare thee to a Summer's Day - or an SLR - or a Leica. Here is where it really gets interesting. First let's look at the SLR / G2 issues. An SLR is much more versatile. The G2 cannot do macro work. It has no lenses longer than 90 mm. The advantage of a G2 over an SLR is its size and its status as a rangefinder. Not only is the body smaller than an SLR, the lenses are much smaller. The subjective difference is even more than the objective difference. A G2 is not that much smaller than a Pentax LX or a Contax S2. However, it seems much smaller and quicker. A G2 system with a body and a few lenses is also actually much smaller and lighter than an SLR system. Additionally, some people feel more connected to a subject when looking through a rangefinder than through an SLR viewfinder. The fact that the rangefinder does not black out for a moment does offer at least a psychological advantage. Another factor is that in a G2, the entire viewfinder image is in focus. Everything appears sharp. In an SLR the viewfinder image comes in and out of focus depending on the how the lens is focused. This is a big difference. Now the waters get really choppy - comparing the G2 to a Leica M6. First the basic differences.... The G2 is autofocus; the M6 is not. The G2 has motorized advance; the M6 does not. The G2 has auto film loading; the M6 does not. The G2 has an electronic shutter; the M6 does not. Notice a trend here? The G2 has a lot of stuff that the M6 does not have. The G2 has a lot of modern features which the M6 lacks. Before you start feeling sorry for the poor ol' M6 user, however, consider that most M6 users relish this lack of features. The M6 is desirable to many photographers exactly because it does not have all of these features. Lets look at some specific issues. First lets consider the feel of the cameras. The G2 is very solid. The M6 is an absolute rock. After using an M6, a G2 feels less solid in comparison. The controls of each are comparable in feel. The shutter release of the M6 feels slightly better than the G2. The shutter speed dial of the G2 feels better. They bodies weigh about the same, although the M6 lenses are heavier. Although the G2 is only slightly larger than the M6, the G2 feels significantly larger. Perhaps this is because of the simplicity of the M6 or maybe it is because the M6 feels so dense. However, some find the controls of the G2 to be better than those of the M6. There is much room for personal preference on this issue. The viewfinder systems are very different. The G2 uses a zoom telescope as a viewfinder. This system varies the magnification of the subject, depending on the focal length of the lens mounted. This looks much more similar to the view from an SLR, since in both, the magnification of the subject varies with the focal length. For longer focal lengths, the subject is magnified more. In the Leica, the magnification remains constant (.72 for a standard M6). For comparison, with a 45 mm lens, the G2's magnification is .57. For example, when a 90 mm lens is mounted on a Leica, the viewfinder magnification remains the same as when a 28 mm lens is mounted. The picture area of the 28 mm lens is virtually the entire viewfinder. The picture area of the 90 mm lens is a small rectangular frame in the middle of the viewfinder. The Leica shows the pictures area by projecting white lines in the viewfinder. These lines (called bright line frames ) form frames that show the picture areas for 28, 25, 50, 75, 90 and 135 mm lenses. The frames change depending on lens mounted. For a normal (45 or 50 mm) lens, the Leica has an advantage. The viewfinder is brighter in the M6. Additionally, since the 50 mm frame does not fill the entire viewfinder, the photographer can also see the area beyond the picture area. This assists in composition. On the other hand, with a 90 mm lens mounted, the frame area on an M6 is pretty small, making it difficult to see what is there. With the G2, the picture area for the 90 mm lens is magnified, making it much easier to see the subject. This also makes critical focusing more difficult. For a 135 mm lens the problems is even more difficult. Of course a G2 does not even have a 135 lens. Focusing is another issue of difference. There is a fundamental difference between the G2's autofocus system and the Leica's pure manual rangefinder system. The G2 is also a rangefinder, but there is not coincident image system as in the M6. The G2 can be focused manually, but this manual focusing is electronic manual focusing - not mechanical. There is no way for a G2 photographer to tell if something is in focus except to rely on the distance readout in the viewfinder on the top of the camera. The G2 lenses do not even have focus rings. The Leica coincident rangefinder sytem is a joy to use for normal and wide angle lenses. It is easy to see and is certain - provided it is properly aligned. This brings us to focusing accuracy. No one complains about the focusing accuracy of normal or wide angle lenses with either the G2 or the M6. They both focus accurately - better than any SLR. But let us look at the focusing accuracy with a 90 mm lens. Both the M6 and the G2 have questions on their records here. There have been many questions regarding the focusing accuracy of the G cameras. Indeed, when the G2 was introduced, it was said to have overcome the sometimes poor 90 mm focusing ability of the G1. Contax has recognized a problem and addressed it. By all reports, the G2 does do better in this regard than the G1, and many photographers report that it is excellent in this regard. However, there have been some comments of focusing inaccuracy with the G2 and the 90 mm lens. After looking into this, there seem to be two reasons. The first, which may be the most common, is that some new G2 photographers are not used to using AF. Simply, they do no realize that the AF sensor area marked in the viewfinder is what the camera will focus on. The G2 does not use a wide area AF - it uses a very narrow AF area. The second reason is misalignment of the AF system in the camera. There seem to be two kinds of misalignment: 1) the AF sensor not being aligned with the AF sensor area indicated in the viewfinder, and; 2) misalignment of the distance adjustment for the AF sensor. I must say, however, that I have never experienced any focusing problems in any of my three G2's. How about the M6 focusing accuracy? Like the G2, the M6 must be properly aligned. Here the alignment is in the very complex but generally very reliable mechanical rangefinder system and lens coupling system. When properly aligned, the M6's focusing accuracy is good enough to allow use of a 90 f2 lens and is good enough for use of a 135 lens at 5.6. Note, however, that even theoretically, the focusing ability of the rangefinder is actually not quite good enough for a 135 lens at f4. Moreover, the focusing ability of the M6 depends on the photographer having very good eyesight in order to see the small picture frame areas for the 90 mm an 135 mm lens. In my opinion, both the G2 and the M6 are fine for 90 mm lenses. The issue of simplicity v. features is very personal. But there are some other issues to address. The first is shutter accuracy. The G2 beats the pants off the M6. The M6's cloth horizontal mechanical focal plane shutter is not nearly as accurate as the G2's vertical metal electronic focal plane shutter. The M6 shutter can often be off by 1/3 to 1/2 stop or more. A well aligned M6 shutter can be within 1/3 stop. One must also remember the M6's limit of 1/1000 shutter speed and flash synch speed of 1/50. These can both be significant limitations. However, it must also be remembered that the M6 shutter functions without a battery. The G2 depends on its two CR2 batteries for its life. Lenses. There is probably not a hotter issue between the two cameras than this one. I must first say that I have not had as much time with the M6 system as the G2 system. So some of this information is based upon personal use and other sources. I'll start by giving you my three conclusions: There is no overall objective difference (family look) between the two lens families. While there are differences between comparable lenses, there is no overall quality difference. These are all very fine lenses and any differences in quality can only be determined by careful testing. The use of a tripod (or not) makes a much larger difference in sharpness than which lens is used. There is no objective family look - at least I cannot see one. Some Leica users, and to a lesser degree some Contax users, talk about a certain family look to their lenses. Photos takes with very good lenses can be differentialed from photos taken with fair quality lenses. But this depends on the quality of the lens - not the manufacturer. Canon, Nikon, etc all make some very high quality lenses. Photos from these lenses will all look good. However, I have never read or heard anyone who has been able to define a family "look" into any objective or scientific terms. Instead, they use vague, descriptive terms like feel, ambiance, rounded, clarity, impact etc..... Moreover, if there is truly a "look", it should be verifiable by an objective blind (so to speak) comparison test. I have never heard of one being done by an objective, disinterested person. For a start, it should be noted that there is a far larger selection of lenses for the M6 than the G2. There are only 6 G2 lenses. The G2 has no lens faster than 2.0. Leica has about 13 lenses with speeds up to f1.0. A few comparisons (my own opinion). The new Leica 21 2.8 aspherical and the G 21 2.8 are equal. The Leica 35 2.0 aspherical is much better than the G 35 lens. The G 45 2.0 is slightly better than the Leica 50 2.0. The G 90 2.8 is slightly better than the Leica 90 2.8. All the Leica lenses are better built than the G lenses. They are more solid. The finish quality of the G and M6 lenses are equal (as opposed to the bodies, where the G cameras are much better finished than the M6's).

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