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A7 A7R A7S 选哪个
http://www.bhphotovideo.com/expl ... odel-suits-you-best
While the Alpha a7, a7R, and a7S share many qualities, they each offer specific features and specs that differentiate them from one another. The list below presents different kinds of photo and video work, and recommends the a7-series camera that's preferable for the application.
Wedding and Event Photography
For weddings and event photography, the Sony a7 and a7S are the best choices—the a7 for its faster autofocusing, and the a7S for its unrivaled low-light imaging abilities, 4K video capture, and a truly Silent Shutter mode.
Portrait and Fashion Photography
The 36.3MP resolution and exacting details offered by its filterless design makes the a7R the clear choice for this application.
Exception: if you shoot portraits or fashion outdoors, the faster maximum sync speeds of the a7 and a7S offer an advantage.
Sports and Action Photography
The fast and accurate autofocus of its Hybrid AF system, and the faster continuous shooting speed make the a7 the best choice for shooting sports and other fast-moving subject matter.
Landscape Photography
With its high-resolution sensor and omitted anti-aliasing filter, the A7R would be a good choice for capturing the details usually important to landscape photography. In addition, fine art landscape photography is often printed in large format, which is supported by the high-resolution a7R.
Exception: when shooting in locations with extreme contrast between the highlights and shadows, the high-dynamic-range capabilities of the a7S would retain more information in the shadows, without overexposing the highlights.
Vintage Lens Users
For the many photographers who are choosing lighter-weight mirrorless cameras in order to utilize compact, high-quality rangefinder lenses, such as those by Leica and Voigtlander, the a7S may be the best choice. Its gapless on-chip lens design improves light distribution across the sensor, reducing the vignetting that can occur when using lenses designed for film cameras.
Photojournalism and Street Photography
With the fastest continuous shooting rate and faster autofocus, the a7 is the way to go for street, documentary, and journalistic applications. In addition, a 1/250-second flash sync helps when shooting with fill flash outdoors, and the electronic first-curtain shutter provides more quiet activation. Normally, this type of photography does not require maximum resolution, and the faster processing speed of smaller files is an advantage in the news world.
Exception: the potential for damage on the street and in the field makes the magnesium-alloy, weather-sealed bodies of the a7R and a7S appealing. Plus, if the utmost silence is a concern, the silent mode on the a7S is a benefit. It is absolutely silent.
Still Life Photography
Resolution and details are paramount in still life work and for this, the a7R with its 36.4MP filterless CMOS sensor, offers the highest resolution and superb details.
Exception: if you're shooting still life in very low light, it might be worth considering the a7S with its low-noise, high-ISO capability.
Night Photography
Here, the a7S has the clear advantage. A native ISO sensitivity to 102,400 (expandable to 409,600) will enable very effective low-light capture. Also, with its wide dynamic range, city lights and dark shadows can be balanced within the frame and the improved signal-to-noise ratio reduces noise at high ISO levels. In addition, AF sensitivity to -4 allows improved AF accuracy in low light.
Nature Photography
The faster continuous shooting and hybrid autofocus system in the a7 allow you to capture images of fast-moving animals. Furthermore, the AF Predictive Control feature on the a7 recognizes movement to or away from the camera and calculates where the subject should be in the instant between continuous shots.
Exception: the a7S has the advantage of better battery life, which will help on long outings into the woods. It also has the silent mode, which is clearly an advantage when photographing wildlife.
Mirrorless Enthusiast
For the user who is ready to make the leap from point-and-shoot cameras to mirrorless, or one who prefers the compact form factor of a mirrorless camera over a DSLR, the a7 is the most affordable full-frame camera currently available and combines the practical control of a smaller camera with interchangeable-lens options and the light-gathering, resolution, and depth-of-field control of a full-frame sensor.
Exception: if you are a photographer who wants to use their camera for producing high-quality video as well as still images, the a7S is the option for you. While all three cameras offer Full HD capture, the a7S stands out with its ability to handle 4K video.
Cinema-Style Video Shooting
The a7S is the best choice for controlled cinema-style video shoots. It offers far better dynamic range, a much more detailed 1080p image with less moiré and aliasing than the other cameras, a more robust XAVC S Codec when shooting in 1080p, a much cleaner image at high ISOs, and the ability to shoot 120 fps slow motion in 720p. Its ability to output UHD 4K video to an external recorder is just icing on the cake, seeing as the a7S is such a formidable performer in HD video capture.
Live Event or Concert Video Shooting
If you're shooting live events or concerts, then you will probably be using telephoto lenses and panning around to follow the action. In situations like this, the a7R would be the best camera of the three. Its better rolling-shutter performance compared to the a7S, and more detailed video compared to the a7, make it the best choice.
Exception: if you're shooting in very high-contrast situations or in very low light and you can get close enough to use a lens wider than 100mm with a tripod, the a7S’s superior overall video quality makes it the better choice.
Documentary Video
For shooting talking head interviews and controlled B-Roll footage, the a7S is a great documentary camera. A full-frame sensor makes it easy to shoot interviews with a defocused background, even in cramped spaces. The high dynamic range and more flexible picture profiles allow you to get B-Roll footage in almost any environment without setting up lights. All three cameras are also compatible with Sony’s XLR adapter, making it easy to get good audio without having to sync in post.
Exception: if you will be shooting handheld, run-and-gun work, consider the a7R. Its rolling shutter is a little better (fast pans and shaky hands don’t mix well with rolling shutters). Plus, the softer overall image on the a7R makes focusing on the fly a little more forgiving.
Film Students
A helpful aspect of the a7-series cameras is that they handle very similarly. They all have the same control layout, the same focus aids, they use the same lenses, and have the same-sized sensor. Once you get used to shooting with one, it’s easy to move to another. Because of this, the a7 might be the best choice for film students. It's significantly cheaper than the a7S or a7R, and the differences in video image quality won't impede your creativity. Having an extra $1,000 to spend on lenses shouldn’t be overlooked.
Exception: if your budget isn't a barrier, the a7S is the best overall video camera.
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2009年澳洲股市回顾(坑3,40% Complete) (2010-1-4) Artcore 
楼主:Wolongshan
发表于 2014-8-18 21:06
