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HP PhotoSmart 912 HP and Pentax team up to make a true SLR digicam with Pentax lens, HP color wizardry, and ample features. Select a topic Reference: Datasheet PhotoSmart 912 Sample Images --------------------------------- 1. Intro and Highlights 2. Executive Overview 3. Design 4. Viewfinder 5. Optics 6. Exposure & Flash 7. Shutter Lag & Cycle Time Tests 8. Operation & User Interface 9. Camera Modes & Menus 10. Image Storage & Interface 11. Video, Power, Software 12. Test Results & Conclusion --------------------------------- Print-Friendly Review Version Additional Resources and Other Links Reader Comments on PhotoSmart 912 Review --------------------------------- Digital Camera Comparometer (TM) --------------------------------- <-- Digital Cameras (Home) <-- Digital Camera Reviews Index <<Viewfinder :(Previous) | (Next): Exposure & Flash>> Page 5:Optics Review First Posted: 3/26/2001

Optics
The built-in Pentax 3x 8.2-25.8mm lens is equivalent to a 34-107mm lens on a 35mm camera. The glass lens has eight elements in seven groups, with one aspherical (distortion correction) element. The apertures range from f/2.5 to f/11, under automatic or manual control. A zoom ring around the lens barrel controls the optical and digital zoom. A spring-loaded plastic lens cap protects the lens, locking inside the lip of the lens barrel when it snaps into place. A set of 49mm filter threads (also inside the lip of the lens barrel) accommodates a variety of accessory lens kits and filters.

At first contact, we found the operation of the zoom ring to be rather disconcerting - It doesn't directly actuate the lens' zoom elements, but rather just controls an internal motor to zoom the lens toward wide or telephoto settings. Really, this is no different than the more typical toggle button on other cameras we've tested, but somehow the presence of a ring on the lens led us to expect it to work the way the zoom lenses on our 35mm cameras do. Like many cameras, the zoom lens on the 912 doesn't have a truly continuous range, but rather moves in small steps from one focal length to the next. (That is, the lens elements appear to zoom smoothly, but the zoom motion will only stop at certain predefined settings.) In the case of the 912, there appear to be a total of 15 steps of zoom in the range from wide angle to telephoto. This is more than many cameras we've tested, but it still doesn't permit absolutely precise setting. (This is a small matter for most users, but we've always found it to be an annoyance - We hope by chiding the manufacturers gently, they'll be motivated to provide zoom lenses with truly continuous actuation.)

Auto or Manual Focus is selected with the left soft key below the LCD monitor. The focal range differs depending on the focus mode -- Auto Focus mode is 1.64 feet (0.5 meters) to infinity, and Manual focus mode is 0.33 feet (0.1 meter) to infinity. Manual focus is controlled with the right and left arrow keys, and the focus distance is reported in the top left corner of the LCD monitor. For Macro subjects, the focus range is 0.07 to 1.97 feet (0.02 to 0.6 meters) in Auto Focus mode only. You can also adjust the autofocus mechanism to AF Lock (sets focus with a press of the shutter button), or Continuous AF (stays in focus continuously), through the Photo Assist submenu in the Capture settings menu.

Though the 912 doesn't offer a true focus lock button, you can manually lock focus by framing the desired portion of the subject in the center of the frame, pressing the shutter button halfway, and then recomposing the shot while keeping the shutter button pressed halfway. Focus is locked until the shutter button is fully depressed or released.

In addition to the AF Focus menu control, you can change the portion of the subject that the autofocus system bases its focus on (in all exposure modes except Auto). The Auto Focus Area button on top of the camera alternates between Wide (default) and Spot focusing. The Wide setting bases focus on a large area in the center of the viewfinder, while the Spot setting judges focus from the very center of the image.

In addition to the 3x optical zoom, the 912 also provides digital zoom up to 2x, which is activated by zooming past the optical zoom range with the zoom ring. The camera's instruction manual reports that the Digital Zoom includes 1.2, 1.5, and 2x settings, though these figures aren't reported on the LCD screen and it's a little difficult to control the amount of Digital Zoom. Instead, a magnifying glass with a plus (+) sign appears in the top right corner to indicate that digital zoom is in use. (Keep in mind that digital zoom only crops and enlarges the center portion of the CCD image, usually resulting in a loss of image quality in the form of lower resolution or excess image noise.)

In our testing, we found the 912's lens to be of good quality, showing almost no loss of sharpness in the corners of the frame. Overall sharpness was a little low, most likely due to conservative in-camera sharpening of the digital images. Optical distortion was fairly high at the wide angle end of the lens' range, where we measured 0.91% barrel distortion. (A bowing out of straight lines along the edges of the frame). At the telephoto end though, distortion was almost unmeasurable. Chromatic aberration was also fairly low, with about three pixels of faint coloration on either side of the black lines in our resolution target, at the extreme corners. This distortion was almost invisible though, because the coloration was so slight. Overall, a good performance.