Fuji XP170: Performance

Performance

Timing is one of the two most important considerations when assessing digital camera performance (the other is image quality). The XP170 comes in a bit slower than average in terms of operational speed. I promised in my "first-look" review to address whether the XP170 is fast enough to function as a general purpose digital camera. The demo photo was shot inside one of our local shopping malls and the lighting is more than adequate for most digicams, however you'll notice that the passerby is blurred, even though she wasn't walking particularly fast. The problem here is the XP170's abysmally slow maximum aperture simply can't gather sufficient light to guarantee a fast enough shutter speed to capture subject-blur free images indoors or in poor lighting. In bright outdoor light subject blur free images can probably be captured with some consistency, however what logically occurs to me is that underwater the light (even in the tropics) is always dimmer than the light above the surface. I suspect that the XP170 could adequately capture coral reefs and other static subjects underwater, but I can't see this camera being able to capture sharply focused images of schools of rapidly moving tropical fish. That's in addition to not being able to freeze skateboarders (or even shoppers) in motion in less than optimal lighting, above water.

Shooting Performance
Even though the XP170 doesn't look like above-water Fuji digicams, under the hood it utilizes the same practical exposure system that made its siblings popular with consumers - so even if you've never used an underwater camera, you can use this one. The Fuji XP170 draws its power from a proprietary Fuji Lithium-ion NP-50A rechargeable battery which is charged (2-3 hours) via the included wall type charger. Fuji claims the XP170 is good for 300 exposures on a fully charged NP-50A battery and based on my experiences with the camera, that number is fairly accurate.

I do a lot of shoot, review, delete, and re-shoot so I rarely keep track of numbers, but this time I was able to watch the numbers a little more closely than usual. After the first full charge I shot 219 exposures before I ran out of juice. I suspect that is easily equivalent to 300 exposures for a photographer who doesn't delete (and re-shoot) 90% of what he shoots. The supplied charger plugs directly in the wall and fully charges the NP-50A in about 2 hours.

The XP170's built-in multi mode flash provides an acceptable selection of artificial lighting options, including Auto (fires when needed), Red-Eye Reduction, Slow Sync, and Off. Fuji claims the maximum flash range is about 10 feet, and that appears to be a fairly accurate claim based on my very limited flash use, however underwater range would obviously be severely shortened.

The XP170 features the same TTL Contrast Detection AF system found on its predecessor. AF modes include - Single AF / Continuous AF (SR AUTO), Center AF, and Tracking AF. In use the XP170's AF seems a bit slower than average. The XP 170's Mechanical Image Stabilization system reduces blur by quickly and precisely shifting the CMOS sensor to compensate for involuntary camera movement. Typically, Image Stabilization systems allow users to shoot at shutter speeds up to three EV slower than would have been possible without Image stabilization. The XP170 saves images and video to SD, SDHC, and SDXC memory media and 95MB of internal storage.

Lens Performance
The XP170's moderate wide-angle to short telephoto (equivalent) 5x Fujinon zoom doesn't extend from the body when the camera is powered up because the lens is housed completely inside the camera body, periscope style.  Periscope style zooms (which utilize mirrors or prisms to reflect the image from the lens opening to the image sensor) are notorious for soft corners, and the XP170 doesn't escape that curse. The XP170's f/3.9- f/4.9 5.0mm - 25.0mm zoom is equivalent to a 28mm - 140mm lens on a 35mm camera. Construction is 13 elements in 11 groups, which means this lens especially complex, for such a short zoom.

The f/3.9 maximum aperture is a bit slow for shooting indoors, but should be adequate for shooting outdoors - at least in decent light. Center sharpness is pretty good overall, but at the wide-angle end of the zoom corners are noticeably soft. I didn't notice any vignetting (dark corners) and both barrel distortion (straight lines bowing out from the center) and pincushion distortion (straight lines bowing in toward the center) seem well corrected. Contrast is balanced and colors are hue accurate. Chromatic aberration is well controlled, but some very minor color fringing is present, especially in the color transition areas between dark foreground objects and bright backgrounds. Zooming is smooth, silent, and fairly quick - although the zoom rocker switch requires a little getting used to.

Video Quality
The XP170's 1920x1080p @ 30fps HD movie mode produces properly exposed and color correct video clips that are remarkably similar to the video clips captured by its competitors. 

The XP170's movie mode can't compete with a dedicated video camera, but it will do nicely for generating e-mail video attachments for friends and family or to post on social networking sites like Facebook and Youtube - especially if you can get some interesting underwater video. Unlike some digicams, the XP170 can be zoomed while in video capture mode and since the lens is entirely inside the camera there is essentially no no motor noise.

The XP170, unlike some underwater digicams including Canon's first generation D10 underwater digicam - is able to record monaural audio.

Image Quality
The image files produced by XP170 are optimized for the bold, bright, colors and flat contrast that many shooters refer to as Consumer Color. Default color is fairly accurate with most colors being a bit more intense than neutral. Reds are a little warm, blues are a bit bright, and greens are a bit too vibrant, but most casual shooters probably won't consider this a fault. Although there is a slight tendency toward underexposure, outdoors in good light the XP170 generally produces well exposed hue-accurate colors and slightly flatter than average contrast. At the ISO 400 setting - noise levels are noticeably higher and there's a perceptible loss of minor detail. I didn't try anything higher than ISO 400.

Additional Sample Images