Five compact digital camera myths and realities

The holidays are fast approaching and geek gift shopping with it. This year I will post several shopping primers for making the best decisions in buying tech gear. This first installment is about compact digital cameras and what features do and don't matter. It's particularly important because geeks used to buying PCs might wrongly think that more of this or that matters for digicams. Misplaced emphasis on the wrong features can lead to disappointing purchases.

Some background: I'm no professional photographer, but I do know digital photographic gear. I bought my first digital camera in 1997, the 1-megapixel Kodak Digital Science D120 (OK, I didn't know better). The D120 was one of the first 1-megapixel compact digicams selling for (barely) under $1,000. I purchased additional compacts from Canon, Kodak, Olympus and Sony over the next couple of years, but no compact satisfied until the 3.3-megapixel Canon PowerShot S20 in summer 2000. I got plenty of use from the S20, including shooting the opening of the first Apple Store in May 2001.

Since 1997, I've used about two dozen different digicams -- compacts and digital SLRs -- from Canon, Kodak, Leica, Nikon, Olympus, Sigma and Sony. These include, since 2007, the Canon EOS 50D, Nikon D200, Nikon D90, Olympus PEN E-P1 and Sigma DP1. When I say that I used these digicams, I don't mean tested.

In this first primer, I'll offer tips specifically for buying compact cameras that also can be applied to entry-class dSLRs. A follow-up post will offer my holiday pics for compact digicams that should satisfy the most discerning gadget geek or photographer -- even the pros. By the way, I define a compact as having a non-removable lens, meaning four-thirds, micro four-thirds and rangefinder digicams belong in a different category.

1. Megapixels don't matter. One measure of PC greatness is processor clock speed or number of cores. Greater often is better, but the same isn't true for compact digital cameras. More megapixels can actually be worse, because of compact digicam's smaller sensor size. Increasing number of pixels over a smaller CCD or CMOS sensor causes distortion, artifacts and grainy appearance -- or noise, as ISO increases.

For many smaller compacts, 5-megapixels delivers optimum performance. I took the picture above in 2003 with the 5MP Canon PowerShot G5, which produces sharper and more pleasing photos than many, newer compacts sporting more megapixels.

Among the compacts I'll recommend in a later post, nearly all are 10-megapixels -- not 12 or 14 MP -- and these cameras are designed to appeal to more experienced photographers. By comparison, more megapixels is usually good for dSLRs, where the sensor size is much larger and the pixels aren't as tightly packed. More typically is better.

Here's another perspective on why more megapixels don't matter. To double the resolution, number of megapixels multiplies by four. So a 12-megapixel image has twice the resolution of a 3-megapixel image. Apple's iPhone camera, at 3 megapixels, may not take the best photos, but plenty of people print or post acceptable images. Meaning: More megapixels isn't necessarily better.

2. Sensor matters more than megapixels. Digicams with larger sensors can produce much better photos even if megapixels are less than a camera with smaller sensor. With larger sensors, pixels are less compacted. As previously mentioned, as pixels compact across a smaller surface, image quality degrades and artifacts increase. For example, photos tend to be noisier as light decreases, in essence because of how little light must spread out over so many pixels.

The effective size of a 35mm frame is 36mm x 24mm, which is the sensor size of the "full frame" Canon EOS 5D Mark II -- a 21-megapixel dSLR. Many lower-costing dSLRs use "single frame" sensors that measure 16mm x 24 mm, such as the 6-megapixel Nikon D70. By comparison, the Canon PowerShot S90 -- a compact I would recommend -- is 10 MP with 1/1.7-inch CCD sensor. The Nikon P6000 sensor is same size as the S90 and a shocking 13.5 megapixels.

Pixel count isn't the only consideration. Smaller sensors require a shorter focal length to achieve the same angle of coverage as larger sensors. This results in numerous photographic irregularities along most of the focal range, such as vignetting.

Sensor quality and size are hugely important, particularly in compacts, where there are already so many compromises compared to dSLRs.

3. A good lens means everything. This rule is more true for dSLRs, where lenses can be swapped. Photo pros know that the lenses are more important than the camera body, and they hold their value and remain useful longer -- decades. Even for compacts, lens is hugely important but often overlooked in the sales process. D`oh, should it be rocket science that the optics -- the glass through which the photos are captured -- matter big time? Some general tips:

• Optical quality matters. For example, Sony uses a higher optical quality "G" lens on its 10-megapixel Cyber-shot WX1/B. Ask about the glass when buying a compact. Canon and Nikon are optics companies.
• Fixed focal length -- "prime" -- or shorter focal length zoom lenses are better; images will be sharper with fewer artifacts. Long zoom ranges are generally undesirable in compact cameras with small sensors and more megapixels.
• The more light the better, particularly for compacts. The PowerShot S90 or Leica D-LUX 4 come with f/2 lenses which let in lots of light, overcoming some of the limitations of the camera's smaller sensors.

4. RAW is more desirable than JPEG. At least RAW should be an option. Most compacts only shoot photos in JPEG format, a flat file that can be manipulated with limitations. RAW isn't a format but raw data coming off the camera's sensor, and it can be manipulated extensively by numerous photo-editing software applications. Example: I've taken pictures at dusk that were too dark because of available light. But the camera focused correctly. Using software, I could change the exposure and fill-light on the RAW image, salvaging the photo. A JPEG photo would have been throwaway.

Some compacts that can shoot RAW: Canon PowerShot G10, G11 and S90; Leica D-LUX 4; Panasonic Lumix DMC-LX3K; Sigma DP1, DP1s and DP2.

5. Compacts don't match dSLR performance or output. I have yet to see a compact digicam that can equal or better a dSLR. But some come close in some areas. For example, the Sigma DP1, DP1s and DP2 all deliver exceptional image quality -- better than even some dSLRs. It's a combination of a high-quality "prime" lens, dSLR-size sensor and unique "Foveon" sensor technology that captures red, blue, green in layers -- reminiscent of film. Color reproduction is exceptional, and there is no discernible vignetting or other artifacts in RAW photos. Disappointingly, these Sigma compacts also are slow shooting, and they're ergonomics are rough, at best.

A different example: I recently started using a Leica D-LUX 4 compact, which has surprisingly fast shutter response. I have yet to see the shutter lag so common in compacts. Shutter response is one of the major benefits of choosing a dSLR over compact. Click. Click. Click. But speed of shooting doesn't change that the Leica camera comes with a smaller sensor and is handicapped by other limitations common to compacts.

The point: Compacts are great, and it's even possible to use one shooting RAW to fill for a dSLR. But holiday shoppers will want a dSLR if better performance, greater photographic quality and choice of lenses are priorities.

In a future post, I will pick the top compacts for Holiday 2009 shoppers. Please watch for it.

[Photo Credits: Joe Wilcox]