Canon EOS D30 Digital SLRCanon's first digital SLR packs 3 megapixels of CMOS sensor into a speedy, compact body! (Smallest/lightest digital SLR as of August, 2000)<<Optics :(Previous) | (Next): Shutter Lag & Cycle Time Tests>> Page 7:Exposure & FlashReview First Posted: 8/27/2000 |
Exposure
As you'd expect, the EOS D30 provides exceptionally complete exposure control.
Standard exposure modes include the usual program, aperture-priority, shutter-priority,
and full manual, as well as some "image zone" (scene-based preset)
modes, and one of the most unique (and uniquely useful) modes we've yet seen,
an Automatic Depth-of-Field mode. The "image zone" exposure modes
include Portrait, Landscape, Close-up, Sports, and Night Scene modes. These
modes preset a variety of camera parameters to make it easier for non-expert
photographers to achieve good exposures in a variety of standard shooting situations.
The full Auto mode takes over all camera functions, making the D30 into a very
easy to use point and shoot camera, albeit a very capable one.
As noted, we were most impressed with the Automatic Depth-of-Field mode. This
mode uses all three autofocus zones to determine the amount of depth in the
active subject area. Once it has determined the range of focusing distances
present across the three zones, it automatically computes the combination of
aperture and shutter speed needed to render all three zones in sharp focus.
This strikes us as a remarkably useful feature, even for professional photographers:
In many situations, you want to keep several subjects in focus, while at the
same time trying for the highest shutter speed (largest aperture) that will
permit that. In practice, faced with such situations, we've generally resorted
to just picking the smallest aperture feasible and hoping for the best. With
the D30's A-DEP mode, the camera takes the guesswork out of this process and
gives you the fastest shutter speed it can manage while still keeping things
in focus. (In playing with this, we were often surprised by how large an aperture
in fact would work: We frequently would have chosen a much smaller aperture
to stay on the safe side.)
We also liked the way Canon implemented the automatic exposure bracketing on
the D30: You can set the total exposure variation (across three shots) at anywhere
from +/- 1/3 EV all the way up to +/- 2 EV. The nice part is that the automatic
variation is centered about whatever level of manual exposure compensation you
have dialed in. Thus, you could set positive compensation of 0.7EV, and then
have the camera give you a variation of +/- 2/3 EV about that point.
Speaking of exposure compensation, the D30 also lets you specify the step size
for EV adjustments. The default is a step size of 1/2 EV, but you can set an
increment of 1/3 EV unit via the LCD menu system. (Frankly, we've always found
that 1/3 EV compensation is just about ideal for digicam: 1/2 EV steps are just
too broad to set critical highlight exposures accurately.)
We
really liked the amount of information the D30 gives you about its exposure,
not only in terms of the settings it's using, but in the form of feedback on
how pictures you've captured turned out. You can select an "Info"
display mode when viewing captured images on the rear-panel LCD screen, which
produces the display shown at right. Notable here is that you not only can see
all the exposure parameters, but you get excellent feedback on the tonal range
of the image itself. One form of feedback is the histogram display at upper
right, which shows how the tonal values are distributed within the image. Histogram
displays are useful for directly seeing how the overall exposure turned out
in an image, but we've found them to be of limited usefulness for making critical
judgments about highlight exposure.
Digital cameras need to be exposed more or less like slide film, in that you
need to zealously protect your highlight detail: Once you've hit the limit of
what the sensor can handle, the image "clips" and all detail is lost
in the highlight areas. The thing is that it's quite common for critical highlights
to occupy only a very small percentage of the overall image area. Because they
correspond to such a small percentage of the total image pixels, the peak at
100% brightness can be very hard to distinguish in the histogram display. To
handle such situations, the D30 blinks any pixels that are 100% white on its
screen, alternating them between black and white. This makes localized overexposure
problems leap out at you, making it very easy to control the critical highlight
exposure precisely. (The sample image shown in the display above is a pathological
example, chosen to show how the feature works: In practice, you'd probably never
overexpose an image that badly.)
Because we didn't notice it until the very day we were due to ship the D30 production
model back to Canon, we didn't experiment very much with the Bulb exposure option
that's available when operating the camera in full-manual exposure mode. Normally,
exposure times are limited to a maximum of 30 seconds in aperture or shutter
priority modes, but in manual mode, you can expose for as long as 999 seconds
by selecting "bulb" mode and holding down the shutter button for as
long as you want the shutter to remain open. Obviously, 999 second exposures
aren't really a practical reality: Sensor noise totally swamps the signal long
before that point is reached. Given how clean the exposures were at 15-30 seconds
in our low-light testing though, it seems that exposures on the order of 60-100
seconds should produce quite usable images. (Particularly if the noise-reduction
system is enabled, and especially if you're shooting at lower temperatures.)
A final feature deserving comment is the D30's separation of the autoexposure
and autofocus lock functions. In consumer-level digicams, half-pressing the
shutter button locks exposure and focus simultaneously. You can use this to
deal with an off-center subject by pointing the camera at the subject, locking
exposure and focus, and then reframing the picture before finally snapping the
shutter. The only problem is that you sometimes need to perform a more radical
recomposition of the subject in order to determine the proper exposure. For
instance, you may want to zoom in on the subject, grab an exposure setting,
and then zoom back out before taking the picture. Situations like that require
locking the exposure independently of the focusing, and the D30 provides for
just such eventualities by way of a separate AE lock button on the back of the
camera, right under your right thumb. A very handy feature indeed, for those
times you need it.
Low Light Capability
This was an area where we were genuinely surprised by Canon's CMOS technology:
Given past experience with CMOS sensors in low-end cameras, we'd expected poor
dynamic range and noise performance. At high ISO values, the D30 is indeed somewhat
noisy, in both the Red and Blue channels. (See our comparative analysis of the
"Three Titans" digital SLRs, which appears separately. Canon does
have a remarkably effective noise-reduction technology that kicks in on exposures
longer than one second though. This is an optional feature, activated by the
Custom Functions submenu on the LCD menu system. (It's also important to note
that this noise-reduction ONLY affects time exposures though: It has no effect
whatsoever on exposures less than one second long, contrary to speculation elsewhere
on the Internet.) We have more coverage elsewhere, but we couldn't resist inserting
a small sample here: The images below were shot at 1/16 of a foot-candle (about
0.13 lux), at ISO 100. This was a 25 second time exposure, an amazingly long
exposure for a digital camera. The image on the left shows the result with no
noise reduction, while the one on the right shows the result with noise reduction
engaged. Needless to say, the noise reduction works incredibly well! Our shots
taken at 1/16 foot-candles were almost as bright and clear as those taken at
full daylight illumination!
Another thing to note about the D30's low light behavior is how well-balanced
the colors are: These shots were taken with the camera set to Automatic White
Balance, and the colors could hardly have been better. Finally, the autofocus
assist light worked quite well out to distances of perhaps 20 feet or so, letting
the camera focus effectively (if somewhat more slowly than at normal illumination
levels) even in complete darkness. Overall, a very impressive performance!
Flash
The EOS D30's built-in flash was very effective in our tests. Canon's rated
guide number of 39 feet (12 meters) at ISO 100 would suggest a range of about
14 feet at f/2.8, a result that agreed well with our testing. We were also impressed
by how accurate flash exposure was, as it didn't seem to be fooled by unusual
subjects such as the light-on-dark of our Davebox flash range test target. (Some
cameras have a tendency to overexpose this due to the dark background.) It's
hard to overstate how easy it was to get exceptional results with it and in
fact, we felt we really had to go out of our way to get a bad exposure! Kudos
to Canon on this feature!
The D30 gives you a great deal of control over flash exposure, allowing you
to adjust flash and ambient exposure independently of each other, in 1/2 or
1/3 EV increments. This makes it very easy to balance flash and ambient lighting
for more natural-looking pictures. The camera also boasts a custom function
for "Auto flash brightness reduction" that is particularly useful
when using the flash for fill illumination in daylight shooting conditions.
With this mode enabled, if the ambient light is above a certain level, the camera
will assume you're using the flash in a "fill" mode, and will automatically
back off its intensity a bit, to avoid washing out the natural lighting.
Another nice touch was the "Flash Exposure Lock" button, which fires
the flash under manual control before the actual exposure, to determine the
proper exposure setting. This struck us as very handy, akin to the more conventional
autoexposure lock function for handling difficult ambient lighting conditions.
Several of the more impressive features of the Canon flash system depend on
the dedicated 550 EX speedlight. (While multiple Canon speedlights will work
just fine with the D30, their previous top-end 540EX unit apparently does not,
so you'll need the new 550EX to fully tap the D30's flash potential. Among these
are true FP (focal plane) flash sync, flash exposure bracketing with external
flash units, and flash modeling. FP sync requires a flash unit to provide uniform
light output for a fairly long duration; long enough for the focal plane shutter
curtain to fully traverse the "film" plane (sensor plane in the case
of the D30). In the case of the D30, this requires a flash duration of 1/200
second. Uniform, long-duration flash pulses like this permit use of shutter
speeds as high as the 1/4000 second maximum that the D30 is capable of. This
can be invaluable when you want to exclude ambient light from the exposure.
We explained Flash Exposure Bracketing (FEB) and flash exposure compensation
above, so won't review those features in the context of external flash operation.
What does deserve separate comment is the "Flash Modeling" feature
of the F550EX speedlight when used with the D30. With a F550EX connected to
the D30, pressing the camera's depth-of-field preview button causes the speedlight
to fire at 70 flashes per second for about a second. This creates the illusion
of a constant light source for your eyes, letting you preview the lighting on
your subject when the flash fires. VERY handy, and likely to save lots of shoot/check/reshoot
time!
As alluded to above, the "X-sync" speed of the D30 is 1/200 second.
(This is the maximum shutter speed that can be used on the D30 when working
with a non-dedicated, FP-capable speedlight.) When used with higher-powered
studio strobe systems, Canon recommends a maximum shutter speed of 1/60 second
or slower, to accommodate the time/intensity profile of such units. Finally,
via a custom function menu setting, you can program the D30 to use a shutter
speed of 1/200 second in aperture-priority exposure mode regardless of ambient
light levels. (We guess this is useful, if you know you're going to be hopping
in and out of flash mode, but other than a convenient preset for the shutter
speed, it's little different than simply using manual mode to set both shutter
speed and aperture.)
A final benefit of the dedicated Canon speedlights is that they carry powerful
autofocus assist illuminators that can extend the range of the built-in AF assist
light of the D30. We don't have any specs on the 550EX strobe, but its illuminator
apparently provides greater dark-focusing range than the D30 can achieve alone.
Continuous Shooting Mode
Among digital SLRs currently on the market, the D30 comes in about midway in
terms of shooting speed. The continuous shooting mode is rated by Canon at 3
frames per second, although our own tests on the evaluation unit timed it at
about 2.7 fps. This is considerably faster than the 1.5 fps of the Fuji S1 Pro,
but a good bit slower than the 4.5 fps of Nikon's D1. Fast enough for you? -
You'll have to be the judge of that. Professional sports shooters will doubtless
want more, but for most situations, we think the D30 will be plenty fast enough.
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