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Canon PowerShot S1 IS Review
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Review
Date: Dec 4, 2004 |
IMAGE QUALITY
The Canon PowerShot S1 IS is a digital
camera targeted to beginner (to serious) amateur
photographers. It has 3.2 megapixel resolution
on a 1/2.7 in. CCD image sensor.
It has an excellent lens which is image stabilized;
this allows the use a slower shutter speed hand
held than would normally be possible (from 2 to
3 stops gain). The image stabilization works really
well in both still and movie shooting mode. At
full telephoto focal length of 58mm (380mm, 35mm
equivalent), the rule of thumb says that the slowest
shutter speed you can use to hand hold the camera
without encurring camera shake is the reciprocal
of the focal length, i.e. 1/380 sec.; I can hand
hold it at 1/60 sec., but not slower, with image
stabilization.
Because of the low megapixel and tiny image
sensor, I was expecting image quality to be somewhat
disappointing (as some reviewers mentioned), but
I was quite surprised to find the images to be
very pleasant straight out of the camera. Image
detail may measure low in some of the reviewers'
studio tests, but actual field images show plenty
enough detail even at full telephoto. I guess
once you get used to 5MP and 8MP image detail,
3MP seems somewhat low. However, we find the overall
image quality of the Canon PowerShot S1 to be
very good, with good image detail and low noise
at ISO 50.
| 10x Optical Zoom
Range |
 |
 |
| 5.8mm
[38mm] |
58mm
[380mm] |
In the above pictures, we show the coverage for
38mm (35mm equivalent), and then the coverage
for 380mm (35mm equivalent). Being able to use
a long focal length hand held (thanks to the Canon
S1's image stabilized lens) is a luxury that you
may easily get used to -- and find hard to do
without.
The auto focus (AF) works well and is very fast
when there's enough light. The Ultrasonic Motor
(USM) is whisper quiet so at first you may wonder
if the focusing mechanism is working at all.
Some reviewers have reported that in low-light
and at the long end of the telephoto, the AF will
hunt or may be unable to lock focus. After experimenting,
this is what I found:
- Since the AF works on contrast detection,
the AF needs an object of enough contrast to
lock on. In low-light, the lack of an AF-Assist
Illuminator (on a Canon digital camera???) does
not help, so yes, the AF will hunt. The AF performs
much better in Continuous AF Mode. The images
below for the ISO and Long Shutter Speed sections
are taken indoors, the first under normal room
lighting (in my case, 2 compact fluorescent
bulbs); and the second one, under my desk so
it's dark enough to require an 8 sec. exposure.
- At first, what I thought to be the inability
to lock focus at the long end of the telephoto
was simply that I was too close to my subject.
You need to be at least 93 cm (3 feet) away
from your subject at the full 380mm telephoto
focal length. The camera will simply not be
able to lock focus on anything closer than 3
feet.
Outdoors, where there is enough light, my review
Canon S1 always locked focus even at full telephoto.
There is, however, a noticeable AF lag, and this
means that the S1 may not be the best choice for
telephoto action photography. However, if you
prefocus and use Continuous Shooting Mode (not
to be confused with Continuous AF Mode), the Canon
S1 lets you shoot at 1.7fps and you should be
able to capture nice action shots.
A word about Continuous Shooting Mode. The best
way to use Continuous Shooting Mode is to fix
the camera on a point and pre-focus. Then when
you trip the shutter release button, it will fire
continuously and capture the action within the
frame. If you move the camera (say you're trying
to follow a subject) you will most probably get
blurred shots since you are introducing camera
shake (unless the shutter speed is fast enough
to freeze action).
The one niggle that every reviewer has mentioned,
and that I agree with, is that the EVF freezes
when the shutter fires. If you are taking one
shot after another, or panning, it is very difficult
to compose properly.
I was pleasantly surprised to find that Canon
has included the FlexiZone AF/AE system into the
Canon S1. Normally the AF frame is positioned
at the center of the viewfinder, but in the Canon
S1, you can move it to almost any section of the
picture area (except the very edges). This is
invaluable for macro and any work requiring precise
focus. For the ISO shots below, I composed the
scene with the camera set on a tripod. Since Allegra's
eye was not in the middle of the scene, I simply
moved the AF frame (press the SET button and use
the arrow keys) to her eye, and voila! the Canon
S1 focuses and sets exposure based on where the
AF frame is pointed to. To return the AF frame
to its center position, I just press and hold
the SET button.
Another nifty feature on the Canon S1 that is
usually available on more expensive digital cameras
is Focus Bracketing. This allows you to focus
on one point and the camera will automatically
take two more pictures, changing the focus slightly
depending on a narrow or wide range you specify
beforehand. For shooting non-moving objects where
the focus is critical, the use of focus bracketing
increases your chance that you will obtain a properly
focused shot.
When all else fails, the Canon S1 allows you
to switch to Manual Focus Mode. FlexiZone AF is
active in Manual Focus Mode: the portion of the
image in the selected AF frame will appear magnified
to allow precise focusing.
| Macro |
 |
| Macro (10 cm / 3.9 in.) |
The Canon S1 lens allows you to focus as close
as 10 cm (3.9 in.) at wide-angle and 93 cm (3
ft) at max. telephoto. FlexiZone AF plus the swivel
LCD monitor makes taking close up shots a delight.
I usually also use the 2 sec. self-timer so as
to avoid camera shake. A nifty gadget available
for purchase for those who take lots of macro
pictures is the optional Remote Controller.
| Auto White Balance |
 |
 |
 |
| AWB |
WB = Fluorescent |
WB = Custom |
As the above pictures show, the auto white balance
sometimes tends toward the warm colours indoors
under fluorescent light. Using the preset WB for
Fluorescent helped a bit, but the best result
is obtained with Custom WB. Outdoors, under natural
light, the AWB works well.
| ISO
Comparisons |
 |
| ISO 50 |
 |
 |
 |
| ISO 100 |
ISO 200 |
ISO 400 |
The 100% crops
above (area delimited by the white square) demonstrate
the noise at the available ISO Speeds of 50, 100,
200 and 400. At ISO 50, as we would expect, noise
is under control and not apparent. At ISO 100
noise becomes visible but is still acceptable.
Upward, noise is noticeably present. I have two
night shots, one taken at ISO 50 and the other
at ISO 400, in the Photo Gallery.
I have also taken the ISO samples above in low-light
to demonstrate the capability of the AF. The room
ambient light from two energy-saving fluorescent
bulbs was not enough for quick focus or hand held
shots. So, I set the camera on a tripod and at
first had a hard time getting focus. Then I realized
I may be too close. A quick check in the User
Guide told me I was too close for the focus to
work properly at full telephoto. Once I moved
back to 93cm (3+ feet), the AF snapped. I used
the 2 sec. self-timer to avoid camera shake. The
AF frame was positioned on Allegra's (of Galidor
fame) left eye.
| Chromatic
Aberrations |
 |
You will find CA wherever there is a strongly
lit background, like in the picture above. There
is CA at the corner delimited by the red square
at top left (reproduced at 100% crop at bottom
left).
| Long Shutter
Speed |
 |
5.8mm, Manual, Evaluative,
8 sec., F8.0, ISO 50
Custom WB, 2 sec. Self-Timer, Tripod Used,
IS OFF, 100% Crop |
The Canon S1 allows the use of a long shutter
speed of up to 15 sec. but only in Shutter Priority
and Manual modes. This allows you to take some
nice night shots. Generally, with CCD image sensors,
noise usually becomes more prominent at slow shutter
speeds. The S1 has special noise reduction algorithms
that automatically kicks in at shutter speeds
slower than 1.3 sec. and you'll notice a slightly
longer processing time before the next picture
can be taken.
To test this noise reduction algorithm, we decided
to take a low-light indoors shot. If you must
ask, this time Bamm-Bamm and I had to crawl under
my desk to find a dark spot for a long enough
shutter speed of 8 sec.
As you can see, AF at this extreme low light
is fine as long as you keep over 9 cm away at
the wide angle setting. The above picture is cropped
to remove all the junk you'll find under my desk.
Custom WB works well, and the background is perfectly
black with no noise.
The last feature we will mention is the histogram.
The histogram is in Playback Mode only. You can
see the histogram by pressing the DISPLAY button
until the histogram displays. The histogram is
invaluable to give an indication of under- and
over-exposure (don't rely on the LCD/EVF since
the brightness is adjustable and may be misleading);
in addition to the histogram, overexposed areas
of the image blink.
Overall, very good image quality for a 3.2MP
digital camera: great image detail, some CA in
certain cases. You should have no problem obtaining
excellent 4x6 in. or 5x7 in. prints, plus the
occasional 8x10 in.
The pictures in the Canon S1 IS Photo Gallery
page provide a good sample of what the Canon PowerShot
S1 IS is capable of. I have provided samples at
800x600 pixels (compressed to Quality 60/100 in
Photoshop Elements). Remember that this version
is of slightly lesser quality than the original
2048x1536 version.
You can safely assume that most macro shots
and slow shutter speed shots required the use
of a tripod. Any image that is adjusted for levels
in Photoshop has "_adjusted" appended
to the file name.
I have defaulted the image size to 800x600 pixels.
For those who have their monitor resolution set
to 1024x728 pixels, everything should snugly fit
and you should not have to scroll to see the whole
image. If your monitor is set to 800x600 pixels
resolution, start the slide show and then scroll
to the right to position the image within your
screen width. Then, press F11 (if you are using
Internet Explorer) to switch to full screen mode,
and the image should fill your screen nicely.
Press F11 again at any time to switch your monitor
display back to normal mode.
To return to this page from the Photo Gallery,
click on the animated graphics of the camera.
Please open and download the original size version
only if you need to and only once
to your hard drive -- and save me some precious
bandwidth. Thanks!
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