What is the right camera for you? The
answer to that depends very much of what your intended use(s) will be.
The perfect, single camera for each and every application does not exist.
If you merely want a camera that is ready to shoot
everyday scenes with friends and family and a bit of scenery from your
vacations, you have a lot of pocket-size automatic point-and-shoot high quality cameras to choose from. You would probably not want to mess
with imaging software except, maybe for printing, so just shop around and
find a camera that provides nice sharp pictures, evenly lit and with a colour
rendition and contrast that meet your personal taste.
However, you might want more than that - such as
taking detailed pictures of nature, either close-up or far away. You may
have special interests in arts or architecture. Maybe you would like to
portray your collection of stamps or coins. You might fancy shooting
portraits of people; you might want to capture the beauty of the sky - day or
In such events, there are more to consider before
you make your choice. An easy - too easy - recommendation could be:
"Just buy a quality digital single lens reflex (SLR) camera. With their
huge list of interchangeable lenses and accessories you can meet any
requirement". But is that so? What about portability? Will you carry it
along wherever you go and use it as much as you could like to be able to?
Portability is obviously a matter of personal
choice and should be put on our list to consider. Let it be stated right
from the outset: I don't intend to discuss the merits of the highly
sophisticated digital SLRs - wonderful instruments as they are. I care
for the compact but more advanced camera that I can carry along under
almost all circumstances; that is ready to shoot whenever I am and which I
can use for both everyday point-and-shoot and for more special
For such a camera there are certain things to
consider that you do not find readily in the documentation you get along
with your purchase. Nor can you
expect the average sales person to be able to give you guidance on the
more subtle ones of the issues that I am going to point to as things you
should consider. Therefore, without being too technical (and I am not a
technician) we should start with a brief look at what the camera
actually does, when it takes a picture and stores it on your memory card
for later use.
What does it do?
We all know that a camera consist of
a lens and a shutter that determines how much light is sent to "some
pixels" where the photographic image is generated and to a screen (the "LCD")
at the back of the camera where we can see what our scene looks like.
How much light reaches our "pixels" is determined by the ambient light
available; how big the aperture is set (the "f-number") and for
how long time the shutter keeps the lens open, ("the exposure time"). Now, in most consumer
cameras the "pixels" are small elements in a so-called charge coupled
device (the "CCD") that have the capacity to build up an electric charge
proportional to the light that hits them. After exposure, our camera
scans each element and reads the amount of charge that was built-up
during exposure. This can then be converted into a grey-scale image.
However, we also want to have colour. This is - speaking again of the
most typical consumer
cameras - achieved by putting a filter in front of each pixel in one of
the three basic colours, (red, green and blue) which, when blended in
different proportions produce all of the millions of colours available
in the final digital image. The sensor basic principle looks like this:
Each pixel builds up a
charge that corresponds to the amount of light of its particular colour
You will note that there are two "green pixels" for each red and blue.
This is partly for manufacturing reasons but also corresponds well to
the fact that the human eye has it highest sensitivity at the green
wavelengths of light. In the red end of the spectrum we don't sense infrared light (as some snakes do)
and in the blue end we don't see ultraviolet light (as some insects do). And, by the
way, most CCDs of this type sense infrared light very well. Just point
your camera with lens open and LCD screen turned on towards your TV
remote control and activate that control - then you will see the flashes
from the control easily on the LCD.
infrared pulses are readily recorded on "digital
film". Here you see the flashes from the Olympus
RM-1 remote control as recorded by a Minolta
Dimage G400 compact camera.
to make a long story short, there are standard mathematical methods
through witch the information of incoming light on one particular pixel
plus the information on the incoming light of the other colours on the
neighbouring pixels are converted to colour information (wavelength =
colour plus luminosity / brightness) on each individual pixel.
This information on colour distribution over the
CCD, together with the overall information on the luminosity and colour
of the ambient light, constitute the elements of our internal "raw" colour
picture. The procedure and hence, the "raw result" is more or less the
same for all cameras based on this sensor type, irrespectible of brand and other
But before the camera can download the picture to
the memory card for later viewing or printing it has to do quite a few
more manipulations and here, different approaches by different
manufacturers begin to come into play:
What does it do next?
In brief, and in layman's terms, the
camera does some or most or all of the following, depending upon the
final output format(s) that will be provided:
1. Substitution for defective pixels
is 100% perfect, and data from known malfunctioning pixels will be
substituted by interpolation from neighbouring pixels.
2. Noise reduction
sensitivity varies a bit from pixel to pixel and small fluctuations are
normally smoothed out at this stage.
3. Transformation of image colour
Depending on the geometry of the CCD and other factors, the "raw" colour
information will be transformed to represent rows and columns of
colour information (as what you have in the final picture).
4. Colour transformation
sensor element will in general respond differently to light of the same
intensity but of different colours and in this step, transformation of
the colour information - as obtained in direct response according to
the specific CCD's sensitivity
characteristics - will be transformed to
an operational, internal colour management system ("a colour space").
Hubble Wide Field Camera CCD
and Human Eye:
Here is an example of the efficiency of a CCD measured at
different wavelengths. By "efficiency" is here meant the ability to
accumulate charge relatively to the amount of light of a given
wave length that falls upon the CCD during exposure. For
comparison, I have inserted a colour diagram for light in the
visible part of the spectrum, which for the normal eye lies
somewhere between 4000 nm (violet) to about 7000 nm (deep red)
of wavelength. Also inserted is - in arbitrary units - a curve
showing the sensitivity of the normal, human eye This is the
lower curve that peaks in the green area around 5050 nm. (1 nano
meter = 10 Angstroms = 0,000000001 meter).
Ordinary CCDs for consumer cameras
may be somewhat different, but the CCD- curve illustrates well
that the CCD responds differently to light of different
wavelengths and that corrections have to made in order to get a
non-biased representation of all colours.
It is also quite obvious that the
CCD "sees" the world in quite a different hue than does the
human eye. Our eyes respond most strongly to the green light;
the CCD (at least in this case) most strongly to deep red into
the infrared light.
5. White balancing
This is correction for the ambient light colour ("light temperature") that was
used to take the photo. High clouds and shadows provide a bluish light;
the sun a yellowish light; tungsten lamps a reddish light and
fluorescent lamps a yellowish-greenish light. Most cameras have an auto
setting plus provisions for pre-setting corrections for common light sources as
per the above. More advanced cameras also have a manual mode for
calibrating the camera response for any, particular light source.
6. Colour depth reduction
cameras work internally with 10 - 12 bits of colour information (levels
from 0 up to 4095) for each colour. This is reduced to the common 8-bit level (8
bits for each primary colour: 0-255,
where 0 = no light at all and 255 = full brightness). You will recognize these levels from almost any colour imaging and painting
software when you pick different colours in or for an image.
If you are unfamiliar with the representation of colours
in 255 levels in an RGB colour space, you may click on the rose to
see a practical example. Here shown in the PhotoImact12
digital imaging software).
Last Rose of 08
Pentax Optio 550 picture at 1/87 sec,
27.8 mm focal length, f/4.2 in macro mode
these figures about the internal workings mean to us, who just want our
pictures out of the camera without the need to be software engineers?
Well we end up with a picture that may at most contain 256 X 256 X 256
different combinations of red, green and blue levels - in other word
some 16.7 million different colours. However, the camera started with
1024 X 1024 X 1024 (10 bits per colour) or maybe even 4096 X 4096 X 4096
(12 bits) of different combinations of levels. Were all these extra
levels useless??? No, they represented a higher "true" dynamic range of
the CCD from highlight to deep shadow. So, if done properly, by
discarding (in a so-called non-linear manner) the "trivial" parts of the
colour information but keeping the "right" parts we may end up with a
picture much richer in detail in both shadow and highlight than would
have been the case had we just started out with gathering colour on an
8-bit level. And that is what interest you and me as users - that this
capability for improving the overall definition of the final picture is
being utilized by the camera designer in an intelligent manner !
7. Colour transformation
internal, working "colour space" c.f. 4. above is now being transformed into a
standard colour space that is being used for the output picture file format, (e.g.
the sRGB system for JPEG-files).
talking fairly big amounts of data. My trusted, old Olympus C50-Z boasts
(we are talking a 2002-release) a 2560 x 1920 pixels = 4.915.200 pixels.
Each pixel carries 8 bits (1 byte) of colour information for each of the
3 colours, meaning that the uncompressed output file will be 14.745.600
bytes = 14.44 MB. Actually, this camera does provide recording and
output of uncompressed
files as an option, but in the more normal SHQ (super-high-quality) mode
output file sizes are only a bit more than 2 MB large. This reduction -
at the cost of some loss in detail - is what compression is all about.
It is done by built-in mathematical algorithms that represent colours of
similar identity as groups of pixels rather than as individual pixels.
Certainly. Most manufacturers have additional features built-in, the
effects of which we can see through experience and comparison, but of
which we have little knowledge. There is limited or no information
available in the public product documentation as to exactly what these features are
and how they are implemented. All we can be sure
of is, that they most likely differ from brand to brand. Some of the
most common features are:
9. Contrast enhancement
people tend to favour pictures with vivid, rather brilliant colours and the right "snap"
in contrast and clarity. The camera manufacturers tend to respond to
that by guessing what degree of additional enhancement will sell the
to the average customer
above. Standard algorithms for sharpening are applied before the images
are being stored on the memory card.
11. Additional noise reduction
exposure times produce noise in the CCD elements and noise will normally
also be amplified if the electronic (ISO) sensitivity is increased. For
that reason, built-in algorithms are often applied to reduce noise. In
most cases camera documentation tells little or nothing
whatsoever about "when", "how" and "how much".
Orion Rising, December 08
(Image somewhat excessively brightened for clarity's
Automatic noise-reduction: The
designers of my Minolta Dimage G400 clearly did not foresee that their
special noise reduction procedure (algorithm automatically applied, but only for
longer exposures) should one day be used on a 15 second exposure of
Orion rising over the treetops one December evening around 8 o'clock.
Click on image to see in more detail the artefacts introduced.
12. Other corrections
applied (again unknown to the user) for corrections relating to design
particulars of the optical system (distortions, false colour fringes/
chromatic aberration, darkening in the corners / vignetting......)
13. Special ("scene") settings
there are often scores of settings available for "special occasions"
such as night scenes, landscapes, birthday parties, weddings, water
Summer, Spring,.......you name it......). Some of these settings may
influence the settings of the camera prior to exposure (e.g. Sports /
Rapid Motion and Night scene settings) but most are presumably just various kinds of
post-processing enhancements through application of some standard
built-in algorithms in the firmware.
just a few words on output formats. There are basically three of the
RAW is not a file format as such. Each
manufacturer uses generic raw formats and file extension names.
Anyway, "RAW" is an output just after step 1. or 2. above. Only,
data is also transferred to a format where it can be exported to and
processed in certain, external computer software. Thus, RAW is not (as of
today) a standard format, but rather a family of output
formats, each giving the user the opportunity to work on almost
pristine data. That is, data that contain the maximum of
information that you may ever get access to. Therefore, great
detail and subtle tones and shades can be reached that are
otherwise inaccessible in the normal in-camera processed images.
But one has to work on each and every picture although some of
the manipulations may be performed in a batch process. For good
reasons, "RAW" is often regarded as the digital equivalent to
analogue negative film.
As discussed above under 8. this is the processed but
otherwise un-compressed RGB-data. Files are large - take the
megapixel-size advertised for the camera and multiply by three.
Most modern cameras do no longer offer this output option but
rather RAW as above together with JPEG as per below or - as is most normal
for ordinary consumer compact cameras - just JPEG.
This is the most common format used. It
offers the possibility for quite efficient compression before
quality loss becomes too visible. Normally, there are more
options such as "Super High", "High" and "Normal" or "Standard"
quality. The difference may be as well in the level of
aggressiveness in compression as in actual reduction in the
dimension (in pixels) of the image. "Increased
here means that more and more pixels of different shades of are
represented as belonging to the same group and as such, shown as
a one, single colour when re-opened in imaging software or
printed - that is: Increased loss of detail.
This is not an image format, but both TIFF and
JPEG standards include a standard for incorporation of camera and
exposure information in the output image file. You do not see
this information in your picture, but any reasonably useful digital imaging
software is designed to read it.
RAW files include similar information plus a
small thumbnail for preview of the picture.
Selection criteria for YOUR camera
this "small and light" introduction we should be properly dressed to
discuss selection criteria that go over and beyond the standard "megapixel
A. Quality optics
This is simply the alpha and omega. Aggressive post-processing and
so-and-so many pixels are no substitutes for mediocre optics.
Quality optics involves the use of sufficiently many individual optical elements in
carefully designed groups to effectively combat optical
distortions at all zoom- and macro settings. Try it out on
linear / regular geometric subjects and study the output
critically. Quality optics also means essentially no chromatic
aberration (colour fringes). If you add on additional optical elements as I do (for
and for copying negative and positive analogue film), inherent problems may increase
B. Quality optics
It just cannot be stressed enough. When I got my Camedia C-900
Zoom in 1999 we had just crossed the magic 1 megapixel barrier and
state-of-the-art was barely approaching 3 Megapixels as I recall
it. Yet, I remember that my humble 1.3 Megapixel Camedia
outscored competing cameras with more pixels in sharpness and
clarity due to its very fine optics, (with 8 lenses in 6 groups)
. By the way: My C-900 cost my family (it was a birthday
present) around 800+ EURO - in 1999 price level !!! I could get
quite a few deluxe cameras for that sum today.......
Yes, that denounced little thing that only shows 80% of the
captured image and exhibits parallax at close range - I just
wouldn't be without it. You will miss it in the glare of the sun
(even if LCD displays have improved over time), you will miss it
if you shoot in low light and you will definitely want to to
turn the LCD display off in a number of special applications
such as stellar constellation photography.
D. Optical Zoom
By today's standard, 3 times optical zoom is pretty much a
(minimum) standard and so it should be. You don't have
interchangeable optics for compact cameras and if you want to
shoot anything more than just simple point-and-shoot wide-field
scenes you will soon want more. If you want to shoot candid
portraits, sports or similar, you should consider something in
the 5-7 times optical zoom range. If you want to capture a bird
at 30 yards distance - forget about standard compact cameras and
go shopping for a camera system with genuine telephoto
capabilities. (Which could be a combination of a decent compact
camera and a spotting scope - see examples on the astro pages of
Almost any zoom system will exhibit some
distortion(s) at certain range(s), but some lenses are better
than others. Preferably, you should try it out before you buy.
(Se more under "macro capability" below).
E. Macro Capability
Most consumer cameras have a macro setting.
If macro shooting (of flowers, insects, stamps or whatever) is
important to you you must try out your camera candidates before
you buy. Firstly, the macro capabilities of some cameras simply
aren't what I would call "macro" - the closest allowable
distance is simply too large for you to get any decent
"magnification". You should normally be able to tell that from
the camera specifications (and if the manufacturer does not
tell, you may have extra cause for suspicion); however, and
secondly distortions may be very grave at close distances and/or
large zoom ratios and this you should preferably test yourself
before you buy.
When you test for
possible distortions, you should try out the optics against
subjects with straight lines and right angles. You will readily
see if a stamp is distorted, whereas a close-up photo of a
flower or an insect may cheat you at first sight.
F. Size does matter
As cameras become ever smaller and in
particular slimmer, the focal length of the optics usually also
decreases - simply because the distance between lens and CCD
becomes smaller. Now, big lenses (: large physical aperture)
with short focal lengths are costly to produce in good quality
and you will note that as the focal lengths have gone down, so
have in general the physical sizes (aperture/diameter) of the
lenses. For shooting of normal scenes this does not really
matter, as the "fastness" or "slowness" of an optical system -
i.e.: how long exposure times are required for extended objects
of a given brightness - depends not on the absolute
physical size of the system but of the ratio between physical
lens diameter/aperture and focal lengths. (The so-called
Thus, a typical 3 X
optical zoom system of today has an f-ratio around f/3.2 in the
wide-field range and around f/5 - f/6 at the 3 X zoom range -
which is apparently - but not quite - the same as digital compact cameras had
in the earlier 2000 years, even though those cameras were usually quite bulky by today's standards.
However, the smaller lenses are not
completely as good as the larger in a number of other aspects:
Light gathering power: What
is said above about exposure times only holds for extended
objects. For point-like light sources such as stars a larger
lens will record more stars than in a smaller one given that
exposure times and CCD sensor sensitivities are the same.
Resolution: Larger lenses
can split objects closer apart than small lenses can. Thus
larger lenses will produce finer details and crisper images
under otherwise identical set-ups and circumstances. Again,
this can be of importance in astrophotography in splitting
close double stars; it may also be of importance in macro
photography and quite generally in greater enlargements of
CCD sensor size: A simple
geometric reflection will tell you that while you preserve
the same field of view in your images the physical size of
the CCD sensor may be reduced as the focal focal length is
reduced - just as it took longer focal length lenses for
medium format (6 x 9 cm film format) cameras to cover the
same field of view as that of standard consumer (24 x 36 mm
film format) cameras. This again has implications for actual
pixel sizes and thereby for noise and light gathering
characteristics, but this is a rather lengthy discussion
that has therefore been referred to a page of its own.
G. After sales support
Now that we have covered the most important
aspects of hardware, namely the optics, let us divert for a
moment and talk about something much more "soft" and immaterial:
How well do the various manufacturers and their local agencies
support their customers?
If you read
camera reviews from camera owners (i.e.: not professional
reviews) on the internet, you may quite frequently find
statements such as "I love it" and "The best camera
that I have ever owned" side by side with statements such as
"I hate this camera" and "I shall NEVER buy a camera
from XXX again". Are consumers really that different or, is
it more likely that those who hate their cameras have had
certain bad experiences when they needed after sales support?
Let us face it: There have been produced a
few truly lousy cameras and a number of mediocre models that
should never have been allowed to reach the market. However, in
general it is impressive that so many hundreds of millions of
cameras have been turned out at lower and lower prices (both
relatively and in absolute figures) at such a comparatively high
quality. But there will always be a few malfunctioning cameras
that slip through quality control and there will always be some
of us who need repairs after some time for one reason or
Here, the manufacturers warranty and
service policies will be put to test and, from my own experience
and from what I have heard from both dealers and owners, there
are indeed substantial differences between the manufacturers (or
is it rather their regional representatives???). When the need
is there, it is not irrelevant whether it will take 4 weeks or
four months to have one's camera repaired - or, whether it will
be serviced at all even after just a few years of ownership.
My trusty old Pentax K1000 - bought in
1981 - was produced and supported for more than 20 years. I
wonder if any of my current digital cameras (they are all about
5 years old now) will be supported 15 years from now ?!?
This is the downsize of the rapid
development and the race for constant releases of new models
with more and more impressive features: The camera model that
you bought a few years ago has already been discontinued, spares
and accessories are no longer available - you cannot even buy a
proprietary battery or a charger from the manufacturer any
On way of getting an idea about this
aspect of after sales support is to visit the manufacturers'
official homepages - and check against the local
representatives' do., if applicable: Search for discontinued
camera models and see, to what degree such are mentioned, what
service is provided and what spares/accessories are available
for these discontinued models. This site has not been made to
recommend or rate one brand over the other, but the Olympus home
pages are very good examples of, how this could/should be done.
Also, I have heard and read that
even within the warranty period, manufacturers tackle warranty
claims very differently. Unfortunately, facts are not readily
found on this subject and myths and facts are not readily
discerned - my best advice is to try find an honest sales
person. To me, after sales support is one of the most important
specs of any camera brand and should be of concern for
everybody: For manufacturers if they wish to maintain customer
loyalty; for reviewers if they want to present really
good, unbiased advice to their readers; for potential
buyers before they end up "hating their cameras"........