image quality in a raw image (above), converted to TIFF,
is superb in all respects. Even when increased in size from
14.4MB to 38MB with Photoshop CS, to make an 11x15"
print at 280dpi with a Canon i9100 printer, image quality
remains surprisingly high, as confirmed by the small section
(below) of the full image. (Raw capture; ISO 50; f/8 at
Photos © 2003, Peter K. Burian, All Rights Reserved
Select raw capture and the G5 records raw data from the CCD sensor. Parameters
such as white balance, exposure, contrast, sharpness and color saturation
are recorded, but not applied. Hence, they can be changed as desired,
using the special File Viewer Utility software (or after-market software
intended for this purpose) in a computer. You can accept the original
in camera settings or override any of them to achieve a different effect.
Although most digicam reviews barely mention a raw capture mode, it is
one of the most valuable features of cameras such as the G5.
Pros And Cons Of Raw
The raw capture mode was available in six previous PowerShot cameras,
but it is particularly appropriate in the G5. That's because this
prosumer model, with its ultrahigh-resolution sensor and multitude of
capabilities, clearly targets the photo enthusiast who is most likely
to take advantage of this option. There are several benefits to raw capture,
versus shooting in JPEG mode and a couple of drawbacks. First, let's
consider the benefits:
·Images made in raw capture are cleaner and more finely detailed.
While a raw file is compressed in camera, "numerically lossless
reversible compression" maintains all data and does not introduce
artifacts as JPEG compression does. A raw image file also maintains a
higher level of quality when the file size is increased in the utility
software or in Photoshop. Consequently, you will be able to make larger
prints that are suitable for framing.
·When you shoot in raw capture mode, the G5 uses a 12-bit ADC converter
rather than a 10-bit ADC used for JPEGs. This improves the color gradation
of the raw files. Later, when converting raw files to TIFF format, you
can save them with 16-bit (per channel) color instead of the 8-bits available
with a JPEG. The image will exhibit a wider range of tones and colors
for the best detail and smoothest gradations. Granted, most image-editing
programs cannot work with 16-bit color, so this is a benefit only for
those who use the new Photoshop CS, with its comprehensive 16-bit support.
the 5Mp Superfine JPEG mode, the G5 produces image of very
high quality, suitable for making superb 8.5x11" prints
and very good 10x13s. But if an image must be cropped--as
this one was, by a full 50 percent--it's best
to start with a raw image because of its inherently superior
quality. (ISO 100; 28.8mm zoom setting; f/8 at 1/250 sec;
raw image converted to TIFF and cropped to eliminate extraneous
·The next advantage is
the most significant. When compared to a JPEG, a raw file offers much
greater latitude for correction of factors such as white balance, exposure,
and color saturation. Open a raw image with the special software and manipulate
it as desired to achieve technical accuracy or an intended effect. When
the image looks close to perfect, save it in TIFF or another format that's
compatible with all image-editing software.
·After converting raw data files, you can save the originals just
as you would save negatives after making prints in film-based photography.
You can later return to any raw file and reprocess it. Use different settings
in the converter utility to produce a different effect: with a slightly
warmer white balance, richer color saturation, and a lower exposure level,
So, what are the drawbacks? In my experience, there are two:
·A raw data file is much larger than a JPEG image so it consumes
a lot more space on a memory card and also slows the camera. In raw mode,
the fastest framing rate is 1.5 fps, versus 2 fps in 5Mp/Superfine JPEG
capture. Note too that the buffer memory can hold up to nine of the best
JPEG images but only three raw data files before the camera must pause
for recording; that can mean missing some shots.
To illustrate the advantage of raw versus JPEG capture,
I made an image with incorrect settings for white balance,
exposure and color saturation (Photo A) in both JPEG and
raw format. I was able to improve the JPEG image (Photo
B) in Photoshop, a complex process requiring all of my skills.
The raw image (Photo C) was quite easy to correct in the
utility software, before conversion to TIFF, and the results
are far superior in every respect.
·The raw file conversion
process can be time consuming: about 40 seconds per image, in addition
to the time required to correct any image parameters. The workflow process
certainly becomes tedious when you must convert dozens of images after
a long trip or a major event.
Raw Capture Mode Evaluation
During my discussions with photo enthusiasts who own cameras with a raw
capture mode, I discovered that few ever take advantage of this option.
Aside from the drawbacks mentioned earlier, they wonder about its value.
After all, most prosumer digicams produce excellent image quality even
in the best JPEG capture mode. And as one friend asked, "Why should
I bother with shooting in raw mode, when I can easily perfect a JPEG image
The answer: It's far more difficult--and sometimes impossible--to
fully correct a JPEG image. Any major adjustments can be more effective
when applied to raw data that has not been processed in camera. That can
be particularly useful when you make incorrect camera settings.
Let's say you were shooting
under sodium-vapor lighting with auto white balance, and your images all
exhibit a strong color cast. Perhaps you inadvertently set spot metering
instead of evaluative metering and many of your images of sky capped mountains
are underexposed. Or you set the color saturation level to High in camera,
and find that skin tones are much too ruddy. No problem if you were shooting
in raw mode. These serious errors (and others) can all be corrected without
damaging the image, in the conversion utility software.
And what about the image quality issues? Well, the G5 certainly produces
exceptional JPEGs, particularly in 5Mp Superfine mode, thanks to the sophisticated
DIGIC processor. While the raw images are slightly superior (without any
digital artifacts or jagged edges) the difference is negligible in 8.5x11"
prints. But in 11x15" prints that I made with the Canon i9100 large
format printer, the results are noticeably better when I started with
a raw file that was converted to TIFF.
Do You Need To Use Raw? Naturally, not everyone needs to shoot in raw
mode. If you find that most of your images are technically excellent,
if your printer cannot generate outputs larger than 8.5x11"--and
if you do not frequently crop images extensively--you'll be
impressed with the 5Mp Superfine JPEG mode. The PowerShot G5 will provide
faster response and you'll save hours of computer time. But if you
are a perfectionist who appreciates the wide latitude of a raw image,
or if you want to make beautiful 11x15" prints, do try the raw capture
mode. Use it particularly for important events, or once-in-a-lifetime
photo opportunities and you'll have extra peace of mind.
The PowerShot G5 is a moderately large camera with magnesium
alloy front panel and a beefy handgrip that holds an oversized lithium
ion battery that seems to last forever. Although it is absolutely loaded
with automatic and advanced capabilities, it offers logical, straightforward
operation. The handsome black exterior sports many analog controls, including
a mode selector dial for quick selection of many options. All of this
assures fast camera operation, reducing the need for a lot of hunting
and pecking in the electronic menus.
During the test period, I made hundreds of images. Subjects included my
daughters during vacation trips, the competitors at a BMX cycling event,
classic automobiles, people enjoying a medieval fair, and the action at
a dragon boat race. While I often used the raw capture mode, I switched
to shooting 5Mp Superfine JPEGs for moving subjects, with continuous autofocus
and high-speed framing for a full series of images. The autofocus system
is not designed for tracking fast action, but it worked perfectly for
series of nine shots of competitors rowing eagerly toward the finish line.
When taking photos of BMX cyclists in single shot autofocus, I found the
one second shutter lag frustrating at times; pre-focusing on my subject
solved this problem, and allowed the camera to provide instant response.
With its many EOS-style features and controls, great speed and versatility,
and delivering superb image quality, the PowerShot G5 is a fine performer
that should satisfy the advanced photo enthusiast. Add a few accessories,
and this 5-megapixel digicam would be a great choice for those who want
an affordable and compact alternative to a D SLR system. The G5 would
also be a perfect first digicam for experienced photographers who want
to start shooting digital images and demand large prints of high quality.
If you fall into either category, or if you simply want to upgrade from
an older camera, the PowerShot G5 should be high on your list of models
· Sensor: 1/1.8" CCD; 5Mp effective
· Capture Modes: Single shot and continuous framing at up to 2.5
fps; to 1.5 fps in raw capture
· Storage: CompactFlash or Microdrive
· Capture Formats: Raw capture; three JPEG quality levels; motion
· White Balance: Auto, daylight, overcast, tungsten, fluorescent,
flash, two custom presets
· Lens: Aspherical 7.2-28.8mm (equivalent to 34-140mm) f/2.0-3.0
optical zoom; up to 3.6x digital zoom
· Closest Focusing Distance: 1.6'; in Macro, 2"at wide
and 5.9" at telephoto
· Sensitivity: ISO equivalent: 50, 100, 200, 400 and "Auto"
· Light Metering: Evaluative, Center-weighted, Spot; AE Lock; exposure
compensation and bracketing selectable
· Shutter Speed Range: 15 to 1/2000 sec
· Flash: Built-in auto flash with forced flash, redeye reduction,
slow sync flash; flash exposure compensation and lock
· Connectivity: USB 1.1 and video output
· Power: BP-511 or 512 lithium ion battery
· Dimensions/Weight: 4.8x2.9x2.8"; 14.5 oz
· Street Price: $649
· Exceptional versatility and convenience of operation; accepts
accessory flash unit, 0.7x to 1.75x lens converters, and (with adapter)
· DIGIC processor produces images with ultrahigh resolution and
excellent color, sharpness, a wide tonal range and very good white balance;
fast processing and large buffer memory allow for quick shooting
· Raw data files offer great latitude for correction in conversion
software; their image quality is superlative, suitable for beautiful 11x15"
· Very low digital noise at ISO 50 and low at ISO 100; moderate
noise even at ISO 400 and in long exposures at night
· Very long battery life
· Underexposes light-toned subjects in evaluative metering; overexposes
with 550EX Speedlite; for better results, apply exposure or flash exposure
compensation; adjust raw images in utility software
· Superb lens, but purple fringing (chromatic aberration) around
ultra-bright highlights at wide apertures
· At wide angle zoom settings, the lens barrel blocks part of the
view through the optical finder
· Autofocus system is very versatile but does not offer automatic
focus point selection
· In single shot autofocus, shutter lag can be frustrating; use
continuous focus, or
pre-focusing, for quicker response
Canon USA, Inc.,
1 (800) 652-2666