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645D 的圖片與感想

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simdavid 主題  | 發表  |   傳送訊息     發表於 2011-4-18 11:17:35
看了這作品不得不分享,作者是Pentaxforums的harklee,原連接在這,建議大家去看一下。 ... -thoughts-645d.html


My final thoughts on the 645d...

These  are my final thoughts on the 645d and a compilation of works for the  past six months. In summary, the 645d is a great value to those who  consider the quality of prints the highest priority.

A. Image Quality

(1) Quality of each pixel most likely exceeds that of any high end DSLR, no idea how it compares to the other digital medium formats.
(2)  Images sharpen very well, compared to d3x, 1ds III or 5d ii, the RAW  files contain finer details and less artifacts when sharpened with the  same parameters in ACR (compared at 100%).
(3) Pan focus is  much tougher for landscape photographers due to larger sensor size. For  pixel peepers, if you demand high quality for each pixel, meaning very  small circle of confusion, the DOF  will always be a problem when you include close-distance objects (e.g.  less than 10ft when you are shooting at 35mm, f/13), focus stacking is  something you may want to consider.
(4) The dynamic range  seems to be no different than any other DSLRs, the specifications from  the manufacturer seem to support my experiences.
(5) ISO 100 produces better images than ISO 200 (even though ISO 200 is default), although I never tested above ISO 400.
(6)  Color rendition is very natural. Red channel tends to be suppressed  compared to the canon DSLRs (maybe it's the other way around, Canon  tends to oversaturate).
(7) TERRIBLE white balance. Especially photographing sunsets and sunrises gives you a number of logistic challenges, the auto WB is almost never right. Need to take mental images of the scene and correct them in RAW converter based on memory.
(8) Diffraction becomes noticeable at f/16, the best aperture seems to be f/11-f/13 for landscape photography.

B. The Camera

(1) Definitely bigger than any top of the line DSLRs, but light for its size.
(2) Ergonomically designed, handles very well.
(3) Feels very solid and well made, the dust / weather seal offers great protection.
(4) Viewfinder is large and bright, displays all essential information.
(5) Mirror is well dampened, lock-up is very useful for landscape shooters.
(6) Electronic level is convenient and accurate, also offered inside the viewfinder.
(7) Very useful dedicated control buttons / knobs for bracketting, mirror lock-up, metering, AF mode, AF, white balance and drive mode.
(8) Battery life is more than enough, purchased three extra batteries, never had to use more than two batteries in one day.
(9)  Separate mounting plate can be attached on the left side of the camera  for vertical shots, very useful since some ball heads cannot support the  weight of the camera when tilted.
(10) 3" LCD is one of the  best features, superb quality. The camera offers fast zoom to check the  focus / sharpness (usually zoom to 14X-16X gives you a good sense of the  100% original).
(11) Auto focus seems accurate, didn't have a chance to carry out precision tests.
(12) Lack of liveview is a major disadvantage compared to high-end DSLRs.
(13)  It takes about 4 secs to review a shot even with Sandisk Extreme 32GB  SDHC cards (30MB/S), (with lens correction off), which can be  frustrating from time to time.

C. Lenses

(1)  Most FA lenses seem to perform very well with the exceptions of FA  33-55mm and FA 45mm. Tested lenses : FA 35mm, FA 33-55mm, FA 45-85mm, FA  55-110mm, FA 80-160mm, FA 45mm, D-FA 55mm, FA 75mm, FA 150mm.
(2) A 35mm marginally outperforms FA 35mm, although the quality of the very edges with a 645 full-frame sensor remains to be seen.
(3) A 35mm seems to offer larger DOF  than FA 35mm focused at the same distance with the same f-number,  probably due to smaller lens diameter. A test will be carried out  shortly.
(4) FA 33-55mm is almost unusuable for pixel  peepers, due to spherical focal plane, it's never sharp from corner to  corner below f/16, so almost always substantially diffraction-limited.  The lens performs better from 35mm to 45mm. Two copies tested, both  calibrated by Pentax Japan.
(5) FA 45-85mm and FA 80-160mm perform slightly better than FA 55-110mm, all three lenses produce very sharp images.
(6)  D-FA 55mm seems a tad softer at the edges than the FA 45-85mm, but  slightly sharper in the center of the frame, both lenses perform very  well.
(7) D-FA 25mm is on its way, will report back in a few weeks.

D. Prints
(1) Tested up to 30"X40", offers great quality and amazing details.
(2)  Expected to offer prints up to 39" X 52" that are sharp upon close  inspection (assuming 1 foot of viewing distance) when properly processed  and sharpened.

E. Suggested Improvements
(1) 80MP full-frame sensor.
(2) Development of tilt-shift lenses.
(3) Liveview.
(4) Improved white balance.
(5) Faster image review.
(6) Articulated LCD.

F. A Nitpick
The factory remote control F has a tiny button. It's tricky to use  because you have to press it with your fingernail and sometime you end  up missing the shot. Aftermarket remote features a larger button,  cheaper and works better.

G. Samples

Ano Nuevo State Park, San Mateo, California (A 35mm)

Golden Gate Bridge, San Francisco, California (FA 35mm)

Davenport Beach, Davenport, California (FA 35mm)

Cataract Falls, Fairfax, California (FA 35mm)

Bonsai Rock, Lake Tahoe, Nevada (A 35mm)

Emerald Bay, Lake Tahoe, California (A 35mm, panoramic)

Hole in the Wall Beach, Davenport, California (A 35mm)

Antelope Canyon, Page, Arizona (FA 45-85mm)

Montana de Oro State Park, Los Osos, California (A 35mm)

Mossbrae Falls, Dunsmuir, California (FA 35mm)

Bonny Doon Beach, Davenport, California (FA 35mm)

Convict Lake, Mono, California (A 35mm)

Pigeon Point Lighthouse, Pescadero, California (FA 45-85mm)

Subway, Zion National Park, Utah (FA 35mm)

Wilder Ranch State Park, Santa Cruz, California (FA 45-85mm)

Mount Shasta, Siskiyou, California (FA 35mm)

Swinging Bridge, Yosemite National Park, California (FA 35mm)

Pfeiffer Beach, Big Sur, California (FA 80-160mm)

Cataract Falls, Fairfax, California (FA 35mm)

Bonsai Rock, Lake Tahoe, Nevada (FA 35mm)

Red Rock Canyon, Clark, Nevada (FA 45-85mm)

Garrapata State Park, Carmel, California (FA 35mm)

Subway, Zion National Park, Utah (FA 35mm)

Bonny Doon Beach, Davenport, California (A 35mm)

South Tufa, Mono Lake, Mono, California (FA 45-85mm, panoramic)

Horseshoe Bend, Page, Arizona (A 35mm, panoramic)

The Watchman, Zion National Park, Utah (FA 35mm)

Valley View, Yosemite National Park, California (FA 35mm)

Mesquite Sand Dunes, Death Valley National Park, California (FA 35mm)






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Post by 橘子駿;929296
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