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The
Camera
The camera is the "earth"
of the
system. To choose the right camera, you have to consider various
factors: the first of them is surely the system itself, that is even
more important than a single camera. With time, it is easy upgrade
the camera with a more advanced model, while it is not easy to
change system if you discover that the one you have chooses doesn't
satisfies your necessities.
A good system
has a wide range of lenses and cameras; it uses top level technology
and it upgrades every year to give the latest and most advanced
tools to photographers. Your choice should not be based just on your current necessities,
you should also consider what you might
need in future. Nowadays, the best systems are Canon
and Nikon, both produces excellent cameras and
lenses, and overall they are on par. I use Canon, but I recommend to
analyze the two systems and to choose the one that fits better your
esigencies.
The image quality
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The image quality is one of the most important aspects
of every camera: even the most advanced camera of the
world wouldn't be a good choice if it had poor image quality. The best way to know the image quality is to try the camera;
if it is not possible, you can read reviews and download image
samples from reliable websites, as the excellent DPreview.
The various aspects of IQ are described in-depth in other
articles, but here I'll summarize the three things to look at.
The resolution determines the
level of detail and the maximum print size of the image. The
number of megapixels gives an approximate idea of resolution, even
though you need to use more precise measurements to know the actual
resolution. Tha said, nearly all cameras currently
available have enough resolution, both for amateur and professional.
The noise is an artefact that
becomes more visibile at high ISO. A good camera must be usable throughout the entire
range from ISO 100 to 1600; obviously,
the highest ISO sensitivities are more noisy, but the noise and
detail must be acceptable even at ISO 1600.
The dynamic range
is the range
of brightness values that can be
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| Low
noise, high resolution and good dynamic range allows
to get excellent image quality. Click on the photo to
view a 100% crop. |
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registered by the sensor: a wide dynamic range is better since
it allows to capture more detail both in shadows and
highlights. Nowadays, nearly all SLR cameras have a dynamic
range of 6-8 stops, that is enough for the majority of the
subjects.
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Fullframe or
APS-C?
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The sensor size is a very important aspect of
the camera. Currently, there are mainly two sizes: the
"FullFrame" (24x36mm) and the APS-C (16x24mm). They
have both advantages and disadvantages.
The APS-C sensor are cheaper, some SLRs with
APS-C sensor cost less than $ 500, while FF is more expensive
(currently the cheapest FF camera is the Canon 5D, that costs
$ 2,200).
The APS-C sensors have a "focal lenght
multiplier" that ranges from 1.5x to 2.0x, that is great
for wildlife and distant subjects: a 70-200mm f/2.8 on an
APS-C camera gives the same angle of view of a 105-300mm f/2.8
(70-200 x 1.5). Moreover, the "crop" of the sensor uses only
the center portion of the image circle, that is the best area
in terms of sharpness and lack of artefacts.
The APS-C sensors allow to design smaller and
brighter lenses than Fullframe : for |
| example, the Olympus 50-200mm
f/2.8-3.5 is brighter, smaller and lighter than the Canon 100-400mm
f/4.5-5.6 L IS.
On the other hand, the APS-C sensors have some
disadvantages, in comparison with FF. The most important one
is that, all other things being equal, the FF sensor will
always have the advantage of higher resolution or lower noise
than APS-C. For example, both the Nikon D2Xs and the Canon 5D
have 12 megapixel, but the latter has much lower noise thanks
for the FF sensor, that offers more surfare to
"collect" the light. Of course with time the
technology will improve, but the FF will always be a step
ahead, and the APS-C will reach sooner its phisical limits:
the 12mp Nikon D2Xs is already limited by diffraction around
f/11 (in other words, if you stop down to f/11 or smaller
aperture you don't exploit the full resolution of the D2Xs,
because the lens does not provide enough resolution to match
the sensor).
Other than that, the "focal lenght multiplier",
that is great for wildlife, is pretty annoying with
wide-angles and lanscapes: a super-wide as the 17-40 is no
longer so wide with an APS-C reflex (it "becomes" a
28-60), while on FF you can use it as it was inteded. Of
course, you need good lenses to get a razor sharp image from
corner to corner, but the majority of L lenses are good
enough: even the super-wide angles (at the Canon 17-40 L)
gives excellent image quality, in particular if you stop down
a little. The larger sensor allows to built larger and
brighter viewfinders, too, that help a lot to compose the
image, in particular in low light.
Overall, the APS-C sensor cameras are a better choice for
beginners, for those who have a limited budgted and for those
who wants to reduce as much as possible the weight and size of
the equipment, while FF
cameras are the best choice for professionals that want the
best image quality and can afford the expense of a pro body
and high quality lenses. |
The autofocus
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The autofocus varies widely depending by the
camera. Other than "Single AF", it is essential to
have a "continuous AF", i.e. an AF system that
tracks the subject as long as you keep helf-pressed the
shutter release. You should be able to select the type of AF
in every exposure Mode (P,S,A,M); avoid cameras that limit the
continuous AF to the "Sport mode." The
number of AF points goes from three to the 51 points of the
Nikon D3 series cameras, but it is not an indicator of the efficiency
of AF; an AF with 10-15 areas might be as good as an AF with
40 or 50 areas. (Personally, I really like the 9 areas AF
module of the Canon 40D) There
are two types of AF sensors: line and cross sensor. The cross
sensor are more precise and |
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sensitive, and usually they are found in professional cameras:
consumer cameras as the 400D have only one cross sensor in the
center AF area, while the 1 series have 19 cross-type sensors. |
Complete control
on the exposure
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Any serious camera must have the four
essential exposure modes: P (Program), S ot Tv (Shutter
priority), A or Av (Aperture priority) and M (Manual). I use
Av for the 90% or my photos, and M for the remaining 10%:
these modes are essential because they allows to control some
of the most important aspects of the image, the exposure and
the depth of field. The "scene modes" (landscapes,
portrait, macro, ect) that are often found in consumer
cameras, insted, are pretty useless.
Other than that, it is important to have an
"Evaluative" or "Matrix" meter, that
calculates the exposure analyzing the entire image with
advanced algorithms. I don't consider essential the other
types of meter, as center-weighted or spot, since Evaluative
allows to get almost always good exposures once you learn to
use it properly, in conjunction with the histogram.
In many situations, you have to compensate the
exposure. The best cameras allows to compensate the exposure
in steps of 1/3 stop, in a range of +/- 5 stops. In the
majority of situations a range of +/- 2 stop is enough, but in
some particular scenes you need to apply |
| strong exposure
compensations, and if the range is limited you have to switch
in manual mode and set the exposure manually. |
A wide range of
shutter speeds
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t is essential to have a wide range of
shutter speed, at least from 30" to 1/4000, plus
"B" (bulb) exposure.
The longest speeds are very useful for
landscapes: in early morning or late afternoon, the best hours
for landscapes, the light is very dim, and you need long
exposures (of course, you should use the lowest ISO setting
and a sturdy tripod). In some situation, you might even need
the B pose, to take exposures of minutes: in this case, it is
essential to have a remote release, to avoid the vibrations
caused by the shutter release.
The fast shutter speeds are useful for action
and wildlife: if you like the photograph the animals in
action, you need very fast SS to "freeze" the
movements. Using wide apertures (f/4 or f/5.6) and ISO 400 I
often get speeds between 1/1600 and 1/4000, that allows to
create amazing action-stopping images.
You should pay attention also to the sincro
flash, that is the fastest shutter speed that you can use with
the flash (at full power). A fast sincro flash is better
because it allows to use flash even in bright light, to
lighten the shadows: the best cameras have a sincro of
1/250. |
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| Shutter
speed: 30" |
Shutter
speed : 1/4000 |
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Wide LCD and
reviewing tools
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The first digital SLRs had small, dim screens:
now the technology has noticeably improved, and the best DSLR
have 3" LCD with a resolution ot 230,000 or even 900,000 pixels.
The viewing angle has improved a lot, too: the most recent
LCDs have a viewing angle of 160 degrees; they are very bright
and easy to read even in direct sunlight.
Othen than a good LCD, there are some
reviewing tools that are essential: the most important is the
Histogram, a graph of the exposure. Once you have learnt to
read the histogram, you can judge the exposure at a glance and
you will rarely miss a photo due to bad exposure. Some cameras
offers even RGB histograms: while they are not essential as
the luminance histogram, they might be useful in some
situation.
The highlight screen shows the overexposed
areas as flashing highlights, and it complements the
histogram. Some cameras have |
| RGB highlights, and
few ones offers even a "shadow alert" that shows the
very underexposed areas. While the LCD screen does not allow to judge accurately the
sharpness of the image, it allows to determine if the image is
noticeably blurred or misfocussed, but you need a good zooming
function. The best cameras offeres a 10x or more powerful
playback zoom to give a close look to the image. Other than
that, it is very useful to have Live View - the possibility to
frame the photo through the LCD screen; it helps a lot in
macro and landscape photography.
Last but not least, you need speed: the camera should be
"snappy" when showing histogram, highlights and
zoom; the photo should appear in the LCD screen as soon as you
press the Display button. If the cameras takes a while to
display the images, you might lose good photo opportunities
because you are busy reviewing the images. |
Wheater sealing
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If you plan to use often the camera under the
rain, in dusty or saindy environments, or in other
"unfriendly" environments, I'd recommend to pay
attention to the sturdiness of the camera body and to weather
sealing. The majority of semi-pro and professional bodies are
pretty sturdy and well built, but only the top professional
cameras (as the Canon 1 series) are weather sealed, i.e. they
have rubber rings around every button (inside the boby),
around the lens mount and in other parts of the body.
Weather seaded camera are not waterproof, you
can not use them underwater, but they can be used without
worries under the rain and in other extreme situations.
Remember that you need a weather sealed lens (as many Canon L
lenses) to get a complete sealing. |
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Other things to
consider
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| A
fast camera allows to capture the action |
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The size and the weight of the body varies
considerably: some consumer bodies, as the Canon 400D, are very
small and light, while the professional 1 series are big and bulky.
If a small camera body is important for you, I'd suggest to consider
a consumer or mid-range body as the Canon 40D and Canon 5D. On the
other hand, a large body often has a better handling, and it
has a second shutter release for vertical format - very useful
if you often shoot in portrait format (or course, if the
vertical grip is important for you, you can always add the
optional battery grip on the smaller bodies).
The menu system should be well organized and easy to
navigate, and the most important functions should be readily
available through the buttons on the camera body or through the main
menu. The camera must have RAW file format (but nowadays all SLRs
offers RAW, only the cheap digicams are limited to JPEG). The other
essential functions include mirror lock up (thats locks
up the mirror some seconds before the actual exposure; it
allows to avoid the blur caused by the mirror slap at slow
shutter speeds) and self timer or remote control, very
important to
avoid the vibrations of shutter release at slow
shutter speeds.
If you photograph action and wildlife, it is
important to have a fast continuous shooting: the best cameras are able to take
about 30 RAW photos at 10 FPS. Many animals moves so fast that it is almost impossible to
press the shutter at the right istant, even if you have fast
reflexes. Shooting at 10 FPS allows to capture the action, and with
digital you don't have to worry about the cost of film: I use
a lot the continuos shooting for wildlife photography.
Nearly all new cameras incorporated a "dust
reduction" function, that shakes the sensor or a filter placed
in front of the sensor to eliminate the dust. I don't consider it
essential (it is quite easy to remove the dust even with an old
camera without automatic dust reduction), but it is a nice addition
that allows to save some time and to change lenses without worrying
about dust on the sensor.
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Do you have
comments or questions?
If you have comments or questions about this
article, feel free to ask in the Juza
Nature Photography Discussion Forum!
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