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Sigma SD9 Sigma's digital SLR uses Foveon's "X3" sensor technology to deliver more detail per pixel! Select a topic Reference: Datasheet SD9 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 SD9 Review --------------------------------- Digital Camera Comparometer (TM) --------------------------------- <-- Digital Cameras (Home) <-- Digital Camera Reviews Index <<Design :(Previous) | (Next): Optics>> Page 4:Viewfinder Review First Posted: 11/09/2002

Viewfinder

The SD9 features a true, TTL (through the lens) optical viewfinder, much like a traditional SLR film camera. The pentaprism viewfinder allows for accurate framing, which Sigma estimates as around 98 percent frame-accurate horizontally, and 97 percent vertically. (Figures that agree quite well with my own measurements.) A diopter adjustment switch just above the eyepiece adjusts the view for eyeglass wearers, with a range from -3dpt to +1dpt. I don't have a calibration for what this translates to in terms of a range of human vision, but did note that the "nearsighted" end of its range was almost enough to compensate for my 20/180 uncorrected vision, something relatively few viewfinders can do. The "sports finder" design also gives a very high viewpoint, making this camera an excellent choice for eyeglass wearers. In the center of the viewfinder display, a central autofocus / autoexposure target mark helps you line up shots. There's also a detailed information readout along the bottom of the display, reporting exposure information such as aperture and shutter speed, focus, exposure compensation, etc.

The actual image area display in the viewfinder is divided into two sections. The central rectangular area of the display is the active image area, and reflects what will be captured in the final image. Outlining this area is a dimmed field of view, dubbed the Sports Finder, as it lets you see what's going on outside the actual frame of view. Thus, if you're tracking a moving subject (as is frequently the case in sports photography), you can see any side action outside the main frame just before it moves into the active area.

The "sports finder" concept has a definite attraction, and the central, transparent portion of the viewfinder quite accurately represents the final image area, but the net result is an active viewfinder area that occupies a rather small portion of the overall field of view. I didn't personally have any difficulty manually focusing based on what I saw in the viewfinder. I do wonder though, whether people with less acute vision might have a hard time focusing due to the much smaller size of the subject in the viewfinder.

For image review and menu display, the SD9 offers a 1.8-inch, color TFT LCD monitor. During image review, limited image information also appears in the display. Pressing the INFO button on the rear panel displays more detailed information, such as the exposure settings and a histogram, which graphs the tonal distribution of the current view of the image, making it easier to determine any over- or underexposure. The camera's index display (aptly titled "Contact Sheet View") shows as many as nine thumbnail images at a time on the screen.

A Playback zoom option enlarges captured images as much as 400 percent, for exceptionally detailed viewing, practically at the pixel level. When you zoom in on an image the display zooms immediately, but shows a very coarse, pixelated version of the image that "fills in" with a detailed display after a few seconds. The same thing happens when you use the arrow pad to pan around in the enlarged image - The display will pixelate while you move around, then fill-in the fine detail a few seconds after you stop.

If the Overexposure Warning feature is activated through the setup menu, a solid red overlay appears during image review, highlighting any areas of potential overexposure. This warning overlay cuts in at a level a little short of absolute saturation, a good design feature in my book. I'd like to see some way of controlling the level at which the warning occurs though, since you sometimes only want to see those parts of the image that actually do go all the way to pure white.

The SD9's histogram deserves special commendation, as it's by far the most useful I've seen in a digicam. Two characteristics make the SD9's histogram noteworthy. The first and most apparent one is that it displays separate curves for the red, green, and blue color components, This can be very helpful for times when you want to avoid losing "shape" (tonal gradation) in the highlights of a brightly colored object. A conventional histogram, which only shows overall brightness (luminance) would give no indication that you were in danger of losing detail in such situations, since the luminance of the object in question could be within acceptable limits, even though one of the color channels was approaching saturation.

By far the biggest benefit of the SD9's histogram readout though, is the fact that it will display the histogram of just portions of the image, based on what's shown at the current zoom level of the playback display. This is really useful, because it lets you zoom in on "problem" areas in an image and really see what's going on. A major weakness of histogram displays on digital cameras is that they calculate and display the histogram for the entire image at once. This gives you a good idea of what's happening with the bulk of the pixels in the image, but we often care a great deal about what's going on in relatively small areas of our photos. Because small areas represent small numbers of pixels, these critical regions may only produce an imperceptible "blip" on the overall histogram curve. Overexposure warnings help somewhat, in that they'll tell you where you're about to lose detail, even if only a small portion of the image is affected, but they're a fairly crude tool because they only show whether or not the exposure has crossed some threshold. With the S9D, you can zoom in on a specific area of the image, and then see a detailed histogram of just that small area, showing you exactly what's happening with the exposure in that part of the subject.

It may seem odd to get excited about something as obscure as a camera's histogram display, but I see this as one of the most useful features of the SD9 for photographers who care about the detail recorded in their photos. It certainly provides a better view of what's happening in your images exposure-wise than anything else I've seen in the last 5 years or so that I've been doing this. Bottom line: Big kudos to Sigma for an exceptionally informative playback display.