佳能的5千萬像素新5D

momomo1997 · 發表於 2015-5-28 18:52:34

本帖最後由 momomo1997 於 2015-5-28 21:08 編輯

佳能的5千萬像素新5D
看來除了像素外，并不比尼康的D810強！

Canon hits 50 -- megapixels, that is
CNET網．February 5, 2015 8:00 PM PST

Editors' note, February 8, 2015: Updated with correction to US prices and addition of Australia and UK pricing.

The rumored high-resolution Canon dSLR finally makes an appearance, geared to take on pricier medium-format cameras like the $8,500 Pentax 645Z and the Nikon D810. The two versions of the camera -- the 50-megapixel Canon EOS 5DS and 5DS R -- pose the question "how much do you really want those extra pixels?"

In the US, Canon expects to charge $3,700 for the 5DS and $3,900 for the 5DS R. They're currently available for preorder in Australia for AU$5,000 and AU$5,300, respectively, and the official prices in the UK are £3,000 and £3,200.

The 5D Mark III will stay in the product line, presumably without any official price drops, and that will still be the videographers' camera of choice -- the 5DS/R lacks a headphone jack and can't output clean HDMI.

As much as we might mock the "moar megapixels" crowd, for professionals, high resolution can be critical. For exceptionally high-quality 600 or 1200 dpi prints, a 50MP photo only translates to about 10x15 inches (25.4 x 38.1 cm) or 5x7 inches (12.7 x 17.8 cm). Even at 300dpi, it's only 29x19 inches (73.7 x 48.3 cm) -- large, but still not 44-inch format large. It also gives professional event photographers the ability to crop out unexpected and unwanted elements of a scene and still have plenty of resolution left for high-quality prints. And some scenes, like landscapes, simply demand as much detail as possible when you're selling your work. The resolution, as well as the large tonal range and the expanded depth-of-field control bestowed by the larger sensor, is why medium-format cameras still exist.

The two 5DS cameras differ in one way: The "R' model cancels the effect of the OLPF (optical low-pass filter) in order to remove the sub-pixel blurring that most cameras need to fix artifacts incurred by turning a pixel array with missing colors into a smooth, full-color image. The price you pay for using an OLPF is lost sharpness, so to obtain maximum sharpness from sensors a manufacturer removes the filter or cancels the effects. Canon chose cancellation to avoid concomitant changes necessary in the optical paths of its lenses.
What's notable

Pixel pitch: The size of the pixels matters: bigger is generally better, since it implies more surface area for capturing light, which in turn delivers a broader tonal range. The 5DS/R has a 4.1-micron pixel pitch. For comparison, the 5D Mark III and 645Z's are 5.3 microns, the D750's is 6 microns and the D810's is 4.9 microns. That means it has the smallest pixel size in its cohort, a result of cramming so many onto a relatively small sensor (36x24mm), at least compared with a medium-format sensor (32.8 x 43.8mm in the case of the 645Z). This doesn't bode well for the tradeoff of resolution vs. image quality.

Body design: The body is pretty much the same as the 5DM3, with a few important, invisible exceptions. To minimize vibration, Canon had to reinforce the chassis, baseplate and tripod socket, and incorporate a new motor rather than the spring-controlled mirror system similar to the 7D Mark II. You'll also be able to set a shutter-time lag in the mirror lock-up mode in order to delay movement and reduce vibration. A little shake goes a long way when you're talking about resolutions this high. It also incorporates the updated viewfinder display of the 7DM2, and upgrades to USB 3.0.

Autofocus and metering: While it retains the autofocus system of the 5DM3, it includes the newer, more advanced metering system of the 7DM2. Canon had to double up the Digic 6 image processors in order to handle all this extra data and the much larger files as well.

Features: While Canon finally adds time-lapse to a dSLR, it looks like it's implemented as a movie function and can only create the movie automatically in-camera. To go with the high resolution there's also a new Fine Detail Picture Style, which gives you more granular control over sharpening options.

My take

So much about this camera hinges on the dynamic range. Without $3,700-quality tonality, you might as well get a much cheaper 36-megapixel D810 which does deliver, and which doesn't compromise on the video capabilities. Plus, the D810 lacks an OLPF, which could make it a much better value than the 5DS R. And of course, it remains to be seen how many full-frame lenses exist that can resolve detail to that extent.

There's a ridiculous amount of pixel peeping in this camera's future.
Comparative specs