Taking up where we left off on Monday, we once again turn our attention to Canon’s evolutionary/revolutionary Canon G1 X. I call the G1 X both evolutionary and revolutionary for a couple of reasons, and I’ll explain those reasons on Friday. In the meantime, let’s look at the eye of this tiger:
The G1 has a 15.1-60.4mm (4X) zoom lens. When paired to the relatively over-sized (for a “compact” camera) 1.5-inch sensor, that gives us a crop factor of a little over 1.85. So, converting that into comparable focal lengths for a Full-Frame 35mm camera, we arrive at an equivalent zoom range of 28mm to 112mm.
What does all that mean to you? Lenses for different size sensors cannot be compared directly, so the old universal 35mm format has become the de facto standard when comparing the focal lengths of cameras. This is why I convert the true focal length to the equivalent 35mm focal length whenever I discuss camera lenses—sort of an apples-to-apples comparison, as it were.
On a 35mm camera, 50mm to 55mm is considered a “standard” or “normal” lens. That means this is the focal length that would reproduce in a 35mm camera the view most comparable to the human eye. Anything substantially less (40mm or so) will produce a wide-angle effect, and anything more (starting around 60mm) is considered a telephoto lens. For candid street photography the preferred focal length is 35mm to 55mm. Landscapes and architecture generally benefit from wide angles—the wider the better with 24mm being my own personal starting point on what I consider adequate for this task (many photographers like even wider, often going down to 18mm or even less). In portrait photography the range you want is from 85mm to around 135, with 105mm being the sweet spot . . . provided that you have a wide aperture lens that can adequately defocus the background behind your subject. More on this last caveat shortly.
Thus, the Canon G1 X has a lens that falls just short of the ideal 24mm for landscape and architecture, covers the middle “normal” range nicely, and even gets you well into the portrait range. But the G1 X is not really suited for portraiture. There’s a catch, and that catch is an inadequate aperture at the telephoto range of the zoom. In photography, the wider the aperture (a lens’ f-stop rating) the shallower the potential depth-of-field. Thus, an 85mm f/2.8 lens is far superior at portraiture than, say, a 105mm at f/5.8, even though 105mm is the better, more flattering focal length.
This depth-of-field problem actually gets worse the smaller the sensor. And the sensor on the G1 X, while class-leading for the compact segment, still falls well below the size of a 35mm sensor. The smaller the sensor, the deeper the depth-of-field at comparable aperture (f-stop) settings. So, while f/5.6 might give an adequately shallow depth-of-field on an 85mm fixed to a true 35mm camera, it won’t get anywhere near the same effect with a G1 X set at the same aperture and zoomed to the same relative focal length. The G1 X will defocus the background at telephoto settings; it just won’t defocus the background anywhere nearly as well as a larger format camera at the same f-stop.
When one considers where this lens excels and where it falls short, once again we can come to the conclusion that the G1 X is clearly aimed at the experienced photographer in need of a backup or smaller camera to complement an existing DSLR system, who at times wants camera raw and full post-processing creative control, and who demands sharper images with higher resolutions than current travel zoom can produce. And, very apparently, the G1 X engineers had static subjects in mind with an emphasis on travel photography.
As good as this lens is, some of the credit for results goes to the camera’s imbedded DIGIC 5 image processor. Below you’ll see samples of both uncorrected and corrected photographs chosen to show the inherent defects in the G1 X lens. These shots were taken in raw and I removed all lens correction algorithms on the left-side photos. The right-side photographs show the results of the DIGIC 5 processor and what you can expect when shooting JPEG.
Take a close look and you’ll notice moderate, visible distortion (curvature) and at least some vignetting (peripheral illumination) in the uncorrected shots. The DIGIC 5 processor all but eliminates these flaws, and it does that very effectively. Obviously, this pairing of lens, processor, and the programming of lens correction data has resulted in a very effective package.
On Friday I’ll reveal details on other G1 X features and present my conclusions.