Picking a Point-and-Shoot Camera: Panasonic DMC-FX7
My wife Daphne likes to look at snapshots and I don’t like to take them, so 25 years ago I bought her a camera. She could never get decent pictures out of the thing, so I bought her another – and another and another and another. She could have stocked a small photo shop with the cameras she never used, film and digital both. Finally, early this year, we came across something she likes.
The camera is a Panasonic DMC-FX7, one of a line of point-and-shoots with different lenses and features but similar innards. This particular model is the size of a cigarette packet with a modest 3x zoom lens, an LCD screen that fills nearly the entire back, and no viewfinder at all.
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The LCD is what attracted Daphne. It is 2.5 inches (6.4 cm) diagonally, bright enough (just) to use in bright sunlight, and fast enough to keep up with slowly moving objects. I find it frustrating because it loses detail in bright sun and cannot handle rapid motion, but Daphne is not skilled enough to notice fine detail as she is shooting, or to follow rapid motion, or frame a picture rapidly. For her the LCD is miraculous. She has never been able to see clearly through any viewfinder but she can see this screen well enough to take good pictures.
A Helping Hand — Several manufacturers offer miniature cameras with equally large LCDs, but at the time we bought it, Panasonic trumped the competition with one important feature: optical image stabilization. (Since then Kodak has announced a model that sounds comparable, the EasyShare V550.) With optical image stabilization, the camera automatically senses the slightest movement and shifts part of the lens to compensate.
It is astonishing to see the difference that optical stabilization has made to Daphne’s photographs. Without stabilization she would have one blurred picture in five but with stabilization I don’t think we have seen one blurred picture in 100, except when she shot from a motorboat without thinking to choose the "Scene" mode and then the "Sports" sub-mode to increase the shutter speed. (More about this later.) I suspect that even somebody with a tremor might be able to use it.
Image Quality — The computer inside the camera is Panasonic’s Venus II image processor, which works very quickly and remarkably well. It rarely turns out an unacceptable picture and seems even to remove colour fringing.
The weak point of the camera is the size of its sensor, which is true of every model in this line and also for every point-and-shoot camera that I know of. They all use tiny sensors stuffed with more pixels than is sensible.
The more pixels that are squeezed onto a sensor, the smaller each light-sensitive cell on the sensor needs to be. In any given amount of time, a smaller cell will be struck by fewer photons of light and will require fewer photons to saturate. Since a smaller cell is struck by fewer photons, it records less dark detail; since a smaller cell saturates sooner, it records less bright detail. Thus, the smaller the cell, the smaller its "dynamic range."
To see how this plays out in pictures, look at the pair on the page linked below. I manipulated both of those photos to make them as effective photographically as I could. Daphne took the top one with her Panasonic, I took the bottom one with my Sigma SD-10. The cells on the Sigma’s sensor have about 20 times the area.
Along with a reduced dynamic range, smaller sensors show more of a certain kind of noise. The number of photons striking a single cell will fluctuate randomly, even when the source of light appears to our eyes to be constant. Larger cells average out more of those fluctuations than smaller cells. The fluctuations show up in photos as random noise like the grain of film, and smaller cells show more it. This is most obvious in dark areas. With a small sensor, noise limits severely how much you can manipulate an image. With the Panasonic, if I brighten a dark tone more than a very little, it turns ugly.
The Overloaded Checklist — Another problem common to point-and-shoots is endemic to consumer electronics: featuritis. The Panasonic cameras suffer from this in spades. Daphne’s camera offers five shooting modes and nine sub-modes, makes sound movies and does simple animations. Depending on the shooting mode, three buttons offer different sets of choices. Although none of this is too complex to figure out in an armchair, it is too confusing to want to deal with when taking snapshots. I rarely use any mode other than "Simple" and Daphne never does. That is why her pictures from the motorboat were blurred.
Although Simple mode usually works fine outdoors, it is not optimal when shooting a portrait by flash. That’s because it has the flash fire an extra time in advance of the shutter, to induce the subject’s pupils to contract and thereby reduce red-eye. This guarantees that you cannot capture a fleeting expression yet it still does not eliminate red-eye. I would prefer to have the flash fire only once – with the shutter – and to fix the red-eye in a computer, which is a trivial task. However, choosing an ordinary flash requires "Advanced" mode. Advanced mode, in turn, requires a dictionary of hieroglyphics, it requires the photographer to remember whether he wants the optical stabilization to be in mode 1 or mode 2, and it permits his forefinger accidentally to change that setting or to defeat it.
(My ideal point-and-shoot camera would have a dispense with a flash button and have a simple mode dial with four positions: automatic flash, no flash, action, and playback.)
One feature that’s available when reviewing photos I expected to be useful – it’s invaluable on my Sigma – but it turns out to be useless on the Panasonic. This is a histogram of the exposure, a graph showing the number of pixels at each level of brightness. On my Sigma the histogram lets me place the exposure exactly. I set the exposure so that the brightest whites are exposed at the maximum level that the sensor can handle, and then I don’t worry about the dark tones. The dark tones are usually too dark to make out on the LCD but I can nearly always bring them out in the computer because the sensor has such a broad dynamic range. In contrast, the Panasonic truncates the range of any picture to match the range of the histogram. When the scene’s contrast exceeds that range, as is commonly the case, I have to decide whether the highlights or shadows ought to be cut off. I can tell that only by looking at the picture; the histogram cannot help at all.
Picking a Point-and-Shoot — As I said at the start of this article, Panasonic makes a number of other point-and-shoots that use the same image processor and use comparable zoom lenses with optical stabilization (all made by Leica). They differ in overall size, size of the LCD, range of the zoom lens, viewfinder, and battery. (Daphne’s DMC-FX7 has a rechargeable lithium battery that ran down after a morning’s sight-seeing. She carries a spare and often needs it.) Some of the lenses zoom from a modest wide angle to a long or very long telephoto. Long telephoto lenses are awkward without a tripod, because they magnify camera movement, but image stabilization ought to make them usable.
Daphne’s camera is so handy that it made me hanker for something smaller and lighter than my Sigma, a camera to throw into a rucksack just in case something should come up. However, I could not abide the Panasonic’s limited dynamic range. I’ve tried to find something in between her camera and mine but I have not been able to. Every model smaller than the Sigma packs so many pixels onto such a small sensor that the cell size works out to be roughly as small as the Panasonic’s. Cameras might be six times the size of the Panasonic but their dynamic range promises to be the same. In short, as the market stands today, I can see buying a $500 camera, and I can see buying a $1,500 camera, but I cannot see buying anything in between.
It seems to me that when buying a digital camera today, the most important question to ask is whether or not you will be satisfied with the quality of good snapshots. When photos from a point-and-shoot are sharp, properly exposed and well composed, they still tend to look like snapshots, not because they have too few pixels but because they have washed-out whites and blocked-in blacks. If that quality is acceptable to you, then buy yourself a point-and-shoot (if possible, one with image stabilization). However, if you want better photographs, you will need to record more detail in highlights and shadows. For that you will need significantly larger cells on the sensor. In today’s market, that seems to mean buying an SLR (and shooting RAW files, not JPEGs: see the last link in this article).
Digital SLR Update — Among digital SLRs, all of those priced below the stratosphere have sensors approximately two-thirds the size of 35mm film. Most of these use similar sensors and hence are capable of similar results, but two stand out as capable of something better. One of these is the Konica Minolta Maxxum 7D, which sells for around $1,400 including a lens, and has a 2.5" LCD. It is the only SLR available with image stabilization in the camera body, not just in the odd expensive lens. This means that it can cope with more camera shake than any other SLR and thus take sharper pictures at slower shutter speeds.
The second anomaly is the Sigma SD-10, also at about $1,400, but including a second lens. The Sigma is marketed to compete with the cheapest SLRs but it actually compares to the most expensive. (For a detailed explanation and review, see the first three links below.) It uses a different kind of sensor than any other camera, a sensor that is sharper than any other and, I suspect, provides somewhat greater dynamic range than any camera except possibly the Fuji FinePix S3 Pro, which uses another unusual sensor and sells for about $2,400 without a lens. None of these cameras includes a memory card, which costs around $100.
If all you want is a better point-and-shoot, then I would go for the Minolta. It has a built-in flash and will be more forgiving of camera shake, which is the snap-shooter’s bete noir. If you are interested in learning photography and think that you might want to take it seriously, then the Sigma is ideal. The cheap lenses that Sigma supply with the camera are fine to start with and you can buy better ones if you begin to find them limiting. With the f/2.8 18-50mm lens ($500), the Sigma becomes a professional’s tool at a bargain-basement price. The Sigma also has simpler controls than any other digital SLR, because it leaves all image-processing to your desktop computer.
Whatever digital camera you buy, to extract the best quality from it, you will need to work on the photos that it produces. What comes out of the camera is not a finished product, it is merely a first approximation by a computer built into the camera. In the link below, I described the complex approach I take with my own photographs. Next week I shall describe a simple one that I worked out for Daphne.
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