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Sony Cyber-shot DSC-F717 Sony updates their already-impressive five megapixel F707, with improved user controls, better color, amazing white balance performance, and an external flash hot shoe! Select a topic Reference: Datasheet F717 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 F717 Review --------------------------------- Digital Camera Comparometer (TM) --------------------------------- <-- Digital Cameras (Home) <-- Digital Camera Reviews Index <<Viewfinder :(Previous) | (Next): Exposure & Flash>> Page 5:Optics Review First Posted: 9/2/2002

Optics
The F717 is equipped with a super-sharp 9.7-48.5mm Carl Zeiss lens (equivalent to a 38-190mm lens on a 35mm camera), and an impressive 5x optical zoom. The aperture can be adjusted automatically or manually, and ranges from f/2-2.4 to f/8 depending on the zoom setting. An additional 2x digital zoom function (10x total zoom) can be turned on and off via the Record menu, but remember that quality is always an issue with digital enlargement. That said, the F717 employs Sony's Precision Digital Zoom, which seems to cause less quality degradation than the normal digital zoom used by some other digicams. (One difference seems to be that the required interpolation is done with raw CCD data, before the JPEG compression is applied.) The F717's zoom control is nice and smooth, with a two-step rocker switch that lets you zoom slowly or quickly. As noted earlier, you can also control digital and optical zoom via the Focus / Zoom ring surrounding the end of the lens barrel, more like a traditional 35mm zoom lens. This made it easy to make small adjustments to the zoom without going too far in either direction, a nice feature for critical framing. A zoom bar appears on the LCD screen, reporting the zoom position, along with an indicator to show when the digital zoom kicks in (if Digital Zoom is activated through the Setup menu).

Combining zoom and focus control together with the F717's lens ring sounds like it should be a fairly minor change in the camera's user interface. In practice though, it makes a very substantial difference in the 717's ease of use and general ergonomics. - I found I could switch back and forth between zoom and focus operation with a quick flick of the MF/AF switch with my thumb, while I turned the ring with my index finger, positioned underneath it. This required a slightly unnatural hand position on the lens, leading me to use the camera in a head-down position, rather than the traditional heads-up position of a conventional 35mm camera. Regardless of the ability to switch back and forth between focus and zoom, having the zoom function avaiable on the lens collar amounted to a great improvement in the fluidity of the user interface.

The rotating lens barrel of the F717 continues to be one of my favorite designs, although the bulky lens takes some getting used to. (Actually, I'm a little conflicted over the design. I love the flexibility it gives, but find it a little awkward to hold in some situations. This is balanced by its making certain shots very easy that would be either awkward or impossible otherwise.) The lens pivots up and down approximately 135 degrees, greatly multiplying your shooting options. It's especially handy for grabbing ground-level macro shots or when holding the camera above your head to shoot over a crowd. The tripod mount on the bottom of the lens barrel provides even greater flexibility when working with a tripod or monopod, allowing you to tilt the camera's back panel for easier viewing. Sony offers both wide-angle and telephoto converters as accessories for the F717, which mount in front of the lens via the 58mm filter threads that line the inside lip of the lens barrel. Having the tripod mount on the lens centerline also makes it easier to align sequences of shots intended for later assembly into panoramas.

*********Focus on the F717 ranges from 19.7 inches (50cm) to infinity in normal mode, and from 0.8 to 19.7 inches (2 to 50cm) in Macro mode. (That's with the lens set to its wide angle position. - At full telephoto, the minimum focusing distance is a substantial 90cm). The Macro function is controlled via the Right arrow button on the Four Way Arrow pad, and is only available when the focus is set to Auto mode (Manual focusing includes the macro range). A Focus switch on the side of the lens selects either Auto or Manual Focus control. (The Focus / Zoom ring controls the zoom function when the lens is set to autofocus operation.). The F717's Autofocus mode uses a five-point contrast-detection system. (The five-point system is a significant advance over the single-point system used in the F707.) Manual focus is set by turning the focus ring at the end of the lens barrel, just as you would a standard 35mm camera lens. When using the Manual focus, a small indicator appears on the LCD screen that shows the current focusing distance in meters as you turn the ring. Also, an Expanded Focus option (activated in the Setup menu) automatically magnifies the image by 2x whenever you rotate the focus ring, providing just enough resolution to accurately set the focus based on what you see onscreen.

I really like the feel of a digicam with a manual focus that works more or less like that on a standard 35mm camera lens. If you're making the transition from a film camera though, the F717's focus ring may take a little getting used to. It isn't directly coupled to the lens elements, but rather just instructs the camera's CPU which way to move the focusing elements. This leads to a sense of disconnection between movements of the focus ring and corresponding focus changes that takes some getting used to. Also, the proportionality between focus-ring movement and focus adjustment seems to be a pretty strong function of the speed with which the ring is turned. If you move the ring slowly, it can take many turns of it to traverse the full focal range, while a quick twist will switch you from infinity focus down to a couple of meters with only a partial rotation. This variable proportionality is doubtless an attempt to deal with the slow slew rate of most "fly by wire" digicam focusing systems. It definitely improves the focus response relative to other cameras I've worked with, but I still find manual focusing on the F717 to be a slightly disconcerting experience.

Similar to the CD400 high-end Mavica model, the F717 features an adjustable AF area, with five selection points available (one at dead center and the other four surrounding the center point). In straight autofocus mode, the focus area selected highlights in the LCD display once focus is locked. You can also opt for a broader center AF selection, rather than the smaller spot area, or manually select the desired AF point, to force the camera to focus on a particular subject and not be led astray by other objects in the field of view.

In any capture mode, the AF point can be controlled via the command dial. A small icon in the upper right-hand corner of the viewfinder display shows the current AF area selection, as do a set of four corner bracket marks in the main viewing area itself. With the control cursor pointing to the AF area icon in the upper corner of the screen, rotating the command dial steps through the five area options plus the auto-area option (the one with the wider set of brackets shown) in sequence. - See the screen shot above right for a view of what this looks like.

I was pleased by the return of Sony's Hologram AF system for low-light focusing, which uses a laser diode and a tiny holographic diffraction grating to project a crosshatched pattern of bright red lines on the subject. The nifty thing about the hologram is that the projected pattern stays more or less "in focus" almost irrespective of subject distance, so there's always a sharp pattern for the camera to focus on. Hologram AF isn't only for low light, as you'll see the camera resort to it in fairly normal lighting as well, if there's not enough contrast in the subject to use the normal contrast-detect AF system. Try pointing the camera at a blank wall in normal home / office lighting, and you'll see the pattern. The screen shot at right shows a camera's-eye view of the Hologram AF pattern, as the lens zooms from wide to telephoto. (This shot was copied from my F707 review - Astute readers will note minor differences in the onscreen information display, but the Hologram AF function works identically.)

In actual use, I found the Hologram AF system made low-light and low-contrast focusing practically foolproof. In fact, it literally was hard to get an out-of-focus photo with the F717, in almost any situation. - This is a significant innovation in AF-assist lighting.

Confused by Apertures and Depth of Field? - Do you know how to use "Front Focus" or "Back Focus" to get *all* your subject in focus? Visit our free Photo Lessons area and click on the lessons "Focusing Up Close" and "Selective Focusing Outside!"