Introduction and Rationale for Purchase
Like two of the other reviewers of this item, I own D-SLR equipment that I use heavily for professional and personal photography. I purchased the SD870 IS for my wife. She had grown tired of trying to use one of my backup D-SLR bodies with a huge lens and external flash whenever she wanted to grab a camera for a quick snapshot. Although I carry my suitcase-sized camera bag with me as much as I can get away with, having a compact point-and-shoot camera makes it possible to capture photos at times and place where I cannot (or would not) bring my huge pro camera bag.
With my other equipment available to me in most cases, my primary objectives for purchasing the SD870 IS was that it be as compact as possible and that it be as fully automatic as possible (for my wife's use). While there are now several good point-and-shoot model offerings that have longer zoom ranges and more manual control options, virtually all are considerably larger in size than the SD870 IS. And since I want to be able to discretely carry the point-and-shoot camera in instances where a larger camera is not practical, the smaller the camera, the more likely it is to be carried with my wife or me. And with the desire for the camera to be as fully automatic as possible, the lack of total manual control is not really a tradeoff for my purposes (or for the purposes of most casual users). I also figured that my wife would virtually never use an optical viewfinder, so omitting that in favor of a huge LCD is a very acceptable tradeoff in my book.
Another important feature that influenced which model I purchased is the zoom range of the SD870 IS. Most camera manufacturers have chosen large zoom range ratios (e.g. 5X or 10X) over less impressive, but more useful, ranges. For most casual users, better wide-angle coverage is more important than extreme telephoto capabilities. Better wide-angle coverage makes a huge difference for shooting outdoor scenery, such as skylines or landscapes, and it also makes it much easier to squeeze a group of friends into the frame in a small room. (Have you ever tried shooting a large group indoors and wished you could knock out a wall, so you could step back far enough to squeeze everyone into the frame?) Conversely, extreme telephoto coverage is not very useful to many, since the flash won't reach very far, handheld camera shake is magnified, and the long end of the zoom range usually lets far less light into the lens. And if you want good results shooting photos from the bleachers of your kid playing sports, point-and-shoot cameras generally do not respond fast enough to do a very good job of capturing fast action, even if you have a mega-zoom. In 35mm camera terms, the zoom on the SD870 IS covers a range equivalent to 28mm to 105mm. Most point-and-shoot cameras start at the equivalent of 36mm or 38mm. The difference between that and the SD870's 28mm wide end of its zoom range is significant, while the 105mm long end of the zoom range is fine for most general purpose needs.
Performance and Use Observations
Overall, this camera has not disappointed, and in some respects, it has impressed and amazed me with its capabilities for its size and price. Shooting in full auto mode produces very good to excellent results in the vast majority of cases. The huge LCD not only works well for framing images, it has proven unexpectedly handy for sharing images with others right from the camera, since the screen is large enough to really get a good look at the images, compared to the much smaller LCD display on my D-SLRs. And the entire camera body looks elegant and is just large enough to be handled with reasonable ease when shooting. But shooting one-handed is a challenge with no good place to rest a thumb.
The camera automatically shifts the ISO sensitivity setting as the camera sees fit. As the other reviewers have noted, ISO 200 shows easily recognizable noise when the image is examined pixel for pixel on screen. But to paraphrase another reviewer's mantra, capturing a less than perfect image is better than not capturing one at all. Along those lines, it is generally better to crank up the ISO setting (at least to 200) if that allows for a faster shutter speed (and less camera shake), better exposure of the background. With the anemic flash and setting the camera to ISO 80 or 100, close subjects shot indoors will almost always appear to be standing in a sea of inky blackness. ISO 200, by contrast, creates a much better chance of capturing at least a little bit of a sense of the background. With all of this in mind, I quickly decided to let the camera do its auto-ISO shifting (which is the only option in full auto mode). Canon thoughtfully offered the ability--even in full auto mode--to limit the auto-ISO range to ensure that the camera will not select an ISO setting above 400, which is where image quality suffers so much that it should be avoided whenever possible. As other reviewers have noted, avoid ISO 1600 like the plague. It irritates me that so many point-and-shoot cameras advertise this level of sensitivity when it produces deplorable image quality and should never be used.
The zooms lens performs well. While it does exhibit some barrel and pincushion distortion at the wide and telephoto ends of the zoom range, respectively, this is not an issue for most users and most images. The lens distortion only manifests itself when straight lines run along the edges of the image. The 28mm wide-angle capability makes this particular model a real standout for its ability to capture images in tight spaces and scenery shots that the vast majority of point-and-shoot cameras cannot.
The face detection feature works extremely well so long as faces are actually facing (no pun intended) the camera. If you try to capture a profile or a candid where the subjects' faces are turned away at all, the face detection feature can be fooled. For those users who prefer to select the appropriate focus target and lock focus before shooting, that option is available, but it requires digging into the menu to make this change (and then again to change it back later).
Accessing settings works about as well as possible, given the very limited number of physical buttons and switches that can fit onto an ultra-compact camera body. Macro, flash, self-timer, ISO, and various display options are all accessible with a single push of a physical button. The whole array of more complex options is available through the easily navigable menu system, but delving into these shooting options will require that most users spend some time studying the manual at least once.
I had not really considered or compared video capture capabilities when making my purchase decision, so playing with movie mode has proven to be a pleasant surprise. It captures excellent quality full VGA video at 30 fps. Beware of the limitations of video mode, however: Once you start recording, focus and zoom are fixed for as long as you continue recording. The digital zoom will work, but as is always the case, image quality suffers noticeably if the feature is used very much. Audio quality is also respectable. Speech is distinct and intelligible. Now that I have discovered how good the video quality is, I find myself using it regularly. Just as I purchased this camera so I could capture images when my D-SLR was too bulky to bring along, it is useful to be able to capture video in situations where it is not practical to have my mid-sized HDV camcorder within arm's reach.
Shutter lag is negligible if and only if you have already pre-focused and keep your finger poised on the shutter release button. If you try to capture a moving child, for instance, without having the chance to pre-focus, you will miss many shots. This is drawback found on virtually all point-and-shoot cameras, but the focus-and-shoot lag time is not problematic for shooting posed snapshots.
Manual white balance is convenient and easy to set, which is the single most important step that users can take to ensure accurate color. While the camera seems to perform well in most situations, there are some cases, such as when shooting under compact fluorescent lighting that is designed to mimic (but not perfectly reproduce) the color temperature of incandescent lights, where manual white balance is essential for accurate color.
Conclusion
The SD870 IS accomplishes precisely what I intended it to accomplish: It captures very good images under a wide array of conditions and in situations where it would be impractical to lug along a larger camera. With a little time invested in reading the manual, there is an impressive array of more advanced features and settings that can be accessed with reasonable ease. The screen (even at the cost of an optical viewfinder) is fantastic. For its size and price, the camera is an excellent choice for most casual shooters.
