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Nikon Coolpix S640 Review
by Howard Creech -  11/5/2009

With a low-profile design, the compact Nikon Coolpix S640 seems to lend itself to street photography. In fact, it calls to mind the approach of post World War I photographers like Robert Doisneau. Doisneau embraced the portability and flexibility of the relatively new 35mm still camera medium and shot everything with a handheld Leica rangefinder. He photographed his subjects where he found them - in the streets of Paris.

Nikon Coolpix S640


Doisneau's diminutive Leica was the mini-cam of his era and if he were working today, I believe he would be amazed at the immediacy, flexibility, capability, and ease of use of today's ultra-compact digital cameras like the new Nikon Coolpix S640.


BUILD AND DESIGN
The brick-shaped Coolpix S640 looks pretty much like every other ultra-compact shirt-pocket digicam out there, but under the hood this camera conceals some important improvements over its predecessors. Nikon claims the S640 is the quickest Coolpix ever - with the fastest start up time of any currently available point and shoot (in its class) and with auto focus as snappy as many entry level DSLRs.


Nikon Coolpix S640

The robustly built metal-alloy/polycarbonate bodied S640 is an auto exposure only digital camera with no manual exposure capability. The S640 is tiny (3.6x2.2x0.8 inches and weighing just 3.9oz) making it close to perfect for capturing candid people shots and a natural choice for street photography - it's responsive, unobtrusive, and eminently pocketable. The S640 is available in black, white, red, or pink.

Ergonomics and Controls
Even though the S640 is thin, tiny, and has smooth surfaces, it is fairly stable in the hands thanks to the nicely placed wrist strap and contoured thumb rest. The S640 is too small for any sort of handgrip, but Nikon could have added a thin finger rail along the right front edge of the camera to improve handling and security.

Nikon Coolpix S640

Dedicated controls are limited, but all buttons/knobs/switches/etc. are logically placed and come easily to hand (for right-handed shooters). In place of the standard compass switch, the S640 features what is essentially a rotary jog dial (which Nikon calls the rotary multi-controller) for super fast menu scrolling and back and forth saved image comparison.

The rotary multi-controller also functions in the familiar compass switch control configuration - up/down (flash/macro), left/right (self timer/exposure compensation), and center "OK" button.

Nikon Coolpix S640

Nikon Coolpix S640

Menus and Modes
The S640's menu system is straightforward - it's consistently simple, user-friendly, logical, and easily navigated. The relatively large 2.7 inch LCD and reasonable font size make reading and using the nominal menus easy. One minor complaint - unlike comparable digicams from several other manufacturers, the S640 doesn't provide direct access (via a "func" or "quick menu" button) to the most commonly changed/adjusted camera settings and functions like white balance, sensitivity, etc.

Here's a breakdown of the S640's shooting modes:

Nikon Coolpix S640
Smart Portrait Mode

Display/Viewfinder

Like most currently available compact point and shoots, the S640 doesn't provide an optical viewfinder so the LCD must be used for all framing and composition, image review, and menu access. The S640's wide-viewing angle Clear Color LCD is relatively sharp (230,000 pixels), fairly bright, hue accurate, and reasonably fluid. The info display provides all the data the camera's target audience is likely to need, but in review mode this information remains on the screen for approximately five seconds before allowing the image to be seen without the info overlay - defeating the nifty rotary jog dials ability to compare saved images by jogging back and forth between them.

Nikon Coolpix S640

The LCD gains up (automatically increases brightness) in dim lighting and can be adjusted to the individual shooters preferences. Some earlier "S" models featured LCDs that were so shiny that they behaved like mirrors, making them essentially useless in bright outdoor lighting - the S640 shows marked improvement over its predecessors with an excellent anti-glare/anti-reflection coating.

PERFORMANCE
Nikon claims the S640 is the quickest Coolpix ever - with the fastest start up time of any currently available camera in its class and an auto focus system that is as speedy as many entry level DSLRs. The S640's performance is impressive, especially so for an ultra-compact, but it is no speed demon. Here's the problem (granted it isn't much of a problem): the camera starts up almost instantly, but users then must wait 2-4 seconds before the camera can/will do anything - menu access, zooming, review, image capture.

Shutter Lag (press-to-capture, pre-focused)

Camera Time (seconds)
Fujifilm FinePix F70EXR 0.01
Olympus Stylus 7010 0.03
Canon PowerShot SD940 IS 0.03
Nikon Coolpix S640 0.04

AF Acquisition (press-to-capture, no pre-focus)

Camera Score
Nikon Coolpix S640 0.29
Canon PowerShot SD940 IS 0.34
Fujifilm FinePix F70EXR 0.42
Olympus Stylus 7010 0.45

Continuous Shooting

Camera Frames Framerate
Fujifilm FinePix F70EXR 3 2.6 fps
Nikon Coolpix S640 2 2.2 fps
Olympus Stylus 7010 2 1.7 fps
Canon PowerShot SD940 IS 0.9 fps

After the camera is fully awake it is pretty quick, but not noticeably quicker than its competition - Shutter lag is 0.04 seconds, and AF Acquisition is a very snappy 0.29 seconds. The S640's continuous shooting mode (which allows users to capture several images in quick succession) is 3 frames in 2.2 seconds. Shot to shot times also seem a bit quicker than average.

Shooting Performance

In addition to being quicker than most of the competition the S640 consistently produces sharply focused and properly exposed images even in lighting that would challenge most point and shoots. The S640 accomplishes this by way of the camera's triple threat Image Stabilization system. It consists firstly of Nikon's standard Vibration Reduction technology, which works by quickly and precisely shifting lens elements in the S640's Nikkor zoom to compensate for camera movement during exposure. Digital Image Stabilization boosts sensitivity (up to ISO 6400) and increases shutter speeds to help further counter shooter instability - especially in low light. Nikon's Motion Detection technology automatically (when needed) manages shutter speed and sensitivity to compensate for minor subject movement during exposure.

The S640's VR system provides only two options - on or off. Finally, Nikon's nifty BSS (Best Shot Selector) mode captures (in rapid sequence) up to 10 shots of the subject and automatically saves the sharpest frame - so even in dismal lighting the S640 produces good images. Not only is the S640 a pretty good "street" camera it also turns out to be a decent indoor/bar/party camera.

Nikon claims the S640's AF is as speedy as many entry-level DSLRs - which is interesting since Contrast Detection type AF systems like the one used by the S640 are generally slower than the phase detection AF systems used in most DSLRs. I didn't have an entry level DSLR on hand to compare with, but the S640's AF is very quick and dependably accurate.

The Coolpix S640's built-in multi-mode flash is a bit on the weak side, but it provides an adequate selection of artificial lighting options, including Auto (fires when needed), On (fill flash), Red-Eye Reduction, Slow Sync, and Off. Nikon claims the maximum flash range (auto ISO) is about 25 feet, but that distance (based on my admittedly very limited flash use) seems wildly optimistic.

The S640 is powered by a 3.7V, 1050mAh Nikon EN-EL12 lithium-ion battery. Nikon claims the S640 (with a fully charged battery) is good for 270 exposures. I do a lot of shoot, review, delete, and re-shoot so I can't really keep track of exposures - but I only charged the battery twice while I had the camera. The supplied Charging AC Adapter (EH-68P/EH-68P) charges the battery in-camera.

The S640 provides 45MB of internal memory and stores images to SD/SDHC memory media up to 16GB.

Lens Performance
Most ultra-compact digicams sport 3x zooms, so one of the nicest features of the S640 is its very good f/2.7-6.6, equivalent 28mm-140mm 5x Nikkor zoom. Starting at a wide angle equivalent of 28mm is impressive, since most ultra-compact digicam zooms start at around 35mm. The S640's lens makes this camera very useful for candid/street shooters because they not only get a little extra width, they also get a little extra reach. This lens has a fairly fast maximum aperture at the wide end but a very slow maximum aperture at the telephoto end of the zoom range.

When the camera is powered up, the lens automatically telescopes out of the camera body. When the camera is powered down, the lens is fully retracted into the camera body and a built-in iris style lens cover protects the front element. Center sharpness is pretty good overall, but at the wide-angle end of the zoom corners are slightly soft. I didn't notice any vignetting (dark corners) and both barrel distortion (straight lines bow out from the center) and pincushion distortion (straight lines bow in toward the center) seem well corrected. Contrast is balanced and colors are hue accurate. Minimum focusing distance (in Macro mode) is 0.8 inches. Zooming is smooth, silent, and quick.

Nikon Coolpix S640

Video Quality
The Nikon Coolpix S640's movie mode is competent, but unexciting and pedestrian - it allows users to capture video clips with monaural sound at resolutions of either 640x480 at 30fps or 320x240 at 15fps. There is no HD mode - with HDTVs proliferating like proverbial bunnies, an HD video mode is becoming something of an expected feature on newer digicams. Shooters can't use the optical zoom (although the optical zoom can be set to whatever length is desired prior to recording) during video capture, but the digital zoom can be used.


Image Quality
Like most point and shoots, the S640's images are optimized for the bold, bright colors, and balanced contrast that many veteran shooters refer to as consumer color - overall color is accurate but noticeably over-saturated. Reds are very warm, blues are bold and bright, and greens/yellows are overly vibrant. Unlike the vast majority of compact cameras, the S640 does a very good job of accurately rendering purples.

Outdoors, the S640 does a great job - image quality is dependably excellent. Exposures are consistently accurate, but lots of sky in the picture often results in slightly overexposed images.

Nikon Coolpix S640
Nikon Coolpix S640

Nikon Coolpix S640
Fujifilm FinePix F70EXR

The S640's Auto White Balance is dependably accurate over a wide range of lighting conditions. In fact, it's the best auto WB I've seen in a camera in this price class - easily equal to Canon's "G" series cameras. The S640's Auto WB mode handled indoor color with aplomb - I had color accuracy problems under mixed indoor lighting with the Nikon Coolpix S620, so clearly Nikon has tweaked their white balance color interpolation a bit for the S640.

Nikon Coolpix S640
Auto White Balance, 3200k incandescent light

In addition to the auto setting there are Manual, Daylight, Incandescent, Fluorescent, Cloudy, and Flash settings.
Indoor image quality is excellent, on par with much more expensive digicams, but as sensitivity automatically rises to overcome lower levels of ambient lighting, noise rises exponentially and color accuracy suffers a bit. Noise levels are quite reasonable up to ISO 400, but they increase substantially after ISO 800.

Nikon Coolpix S640
ISO 100
Nikon Coolpix S640
ISO 100, 100% crop
Nikon Coolpix S640
ISO 200
Nikon Coolpix S640
ISO 200, 100% crop
Nikon Coolpix S640
ISO 400
Nikon Coolpix S640
ISO 400, 100% crop
Nikon Coolpix S640
ISO 800
Nikon Coolpix S640
ISO 800, 100% crop
Nikon Coolpix S640
ISO 1600
Nikon Coolpix S640
ISO 1600, 100% crop
Nikon Coolpix S640
ISO 3200
Nikon Coolpix S640
ISO 3200, 100% crop
Nikon Coolpix S640
ISO 6400
Nikon Coolpix S640
ISO 6400, 100% crop

Additional Sample Images
Nikon Coolpix S640 Nikon Coolpix S640
Nikon Coolpix S640 Nikon Coolpix S640
Nikon Coolpix S640 Nikon Coolpix S640

CONCLUSIONS
Compact cameras have always been popular (at least in part) because they're unobtrusive and not intimidating to subjects. The inconspicuous little Nikon Coolpix S640 should fit right in - it does a remarkably good job across the board and it's tough enough to go just about anywhere. Auto focus speed is on par with many entry-level DSLRs and the S640 is as fast or faster than any camera in its class. Image quality is dependably very good to excellent with balanced contrast, bold bright colors, and acceptable noise levels up to ISO 800. Chromatic aberration (purple fringing) is very well controlled, and the 0.8 inch macro shooting capability is very useful. The S640's triple threat VR system is also a welcome feature.


The Nikon Coolpix S640 provides users with an impressive mixture of versatility, ease of use, and operational speed to efficiently and effectively meet the needs of a surprisingly diverse group of shooters. The S640 is an excellent general-use digicam that is so simple to operate that even absolute beginners can capture stunning images. The S640 is tiny, it's fast, and it consistently delivers first-rate images of both static and active subjects - making it a great choice for family photographers and casual shooters looking a stylish ultra-compact digicam capable of capturing great images outdoors and indoors.

Unlike most of its competition, the Coolpix S640 will also appeal to candid/street/documentary shooters looking for a low-profile picture machine with a little extra reach that's quick enough to capture the decisive moment. The S640 also offers hikers, backpackers, off-trail bikers, extreme sports fans, and adventure travelers lots of photographic potential in a small, light-weight package.

Pros:

Cons: