Hello once more to all those dedicated souls,
This is Part 4b of my notes and comments on digital cameras for bird
photography.
In this part I will discuss: Resolution....a simple explanation.
(Part 4a discussed the CCD Pixel Count.)
The term 'Resolution' now needs to be discussed.
Normally, Resolution is defined as the number of dots or pixels (in an image)
per (linear) inch.
(Note the reference to inches; it's odd but that's the way it's done.)
This definition is relevant for printer settings; usually the more pixels per
inch the higher the resolution and thus the better the image.
However, Resolution is also used to refer to the number of dots or pixels in
total in an image, expressed in the form 1600 x 1200, for example (wide x high).
A 2 mega-pixel camera will produce an image approx 1600 pixels wide by 1200
pixels high. A 3 mega-pixel image will be approx 2048 pixels by 1536 pixels
high.
The concept of resolution and picture size is a difficult one to come to grips
with.
Several things need to be noted:
No matter what camera you are using, lenses being equal, you will end up
with the same image.
However, a 3 mega-pixel image will contain more dots and therefore more
'information' than a 2 mega-pixel image of the same scene.
When displayed on a computer screen the 3 mega-pixel image will be bigger than a
2 mega-pixel image but if you want to print either image you can choose the
final size yourself.
As an example of how big the image could appear if viewed at full size, a
standard 17 inch PC monitor screen (Macs are slightly different) is
approx 1024 pixels wide. Compare that with the sizes of the images
described above.
Of course, it is always possible to view images at reduced size on a computer
screen; this is usually how you would view such images as, at full size, they
would probably be much bigger than the screen you are looking at now.
The thing to remember is that the more pixels in an image the more information
you have to work with when manipulating the image in an image software program.
Small objects in a scene will usually be more defined.
However, the more pixels in an image the bigger the file size and the more space
it takes up on your computer hard-drive.
Also big image files require more computing power and more computer memory.
Note: it is still possible to work on large image files with a computer with a
'slow' CPU (the engine of the computer) and but plenty of RAM (the 'working
area' of the system) is absolutely necessary otherwise it may not be possible to
'load' the file into your image software program.
When viewed on a TV screen the image when displayed directly from the camera
will always fill the screen no matter what size the image sensor is, however, a
3 mega-pixel image will look a lot better than a 2 mega-pixel image spread over
the same area.
In a 'conventional' camera the scene being photographed is registered directly
onto the film as the light coming in through the lens reacts with the chemical
coating on the plastic base of the film strip.
A 'developing' step is carried out with more chemicals outside the camera.
In other words, basically a simple mechanical/chemical process is used.
The quality of the final image is dependant on the particular formula of
chemicals used.
With a digital camera the light from the scene is registered by the CCD (sic)
and converted to electrical values and stored as data on the storage media card.
These electrical values are calculated using mathematical algorithms (apparently
a term obtained from the name of an Arabian mathematician).
These algorithms are, naturally, quite complex and the quality of the final
image depends on the quality of the algorithms used in the micro-processor in
that particular camera.
It seems that there are as many different algorithms as there are cameras which
means that picture quality is likely to vary noticeably from model to model
depending on the 'artistic' bent of the person developing the algorithm.
These algorithms (have I got a fetish about this word?) are getting better with
each new model of digital camera but I still feel that many images have a
distinct 'digital' look about them.
I would describe the pictures my Olympus C-700 produces in this way:
A shot of a particular scene taken with a 35mm film camera would have a warm
tropical summer's day look about it whereas the shot from the digital camera
would have a cold, dry winter's day look.
One explanation for this is that the algorithms (sigh!) used in the C-700 have
produced a touch too much 'sharpness' in the image.
To 'sharpen' a digital image is to try to make the image appear more in focus.
Another problem with images from the C-700 is that with 'default' settings there
is a slight blue cast often with a red cast on edges of objects especially at
high magnifications.
All of this indicates that digital images (from an Olympus C-700 at least) have
a long way to go before they are the equal of film based images.
However, as I said before, if you are not wanting to win prizes the images
obtained are still usually quite acceptable......to me, at least.
If anyone would like to see examples of the images I have taken with the Olympus
C-700 Ultra Zoom, contact me at and I will send you a
couple of JPEG versions as e-mail attachments.
Yet to come:
- Viewfinder types;
- LCD monitor screens;
- Storage media;
- Flash;
- Accessories;
.....Lens and filters;
- Power;
- Digiscoping.
More soon,
Bob Inglis
Woody Point
Queensland
Australia
(Disclaimer:
Please note that these are my personal opinions gained from personal experience
and observation; other people may have other opinions and different experiences.
What I have written below is not intended to be absolute.
Anyone contemplating purchasing a digital camera for any reason or purpose would
be advised to seek advice from other sources as well.
Note that, except where a particular model of digital camera is mentioned, these
comments and notes are meant to be general by nature.
These comments and notes are not intended to be an endorsement for or a
statement against any particular brand or model of digital camera; they are
intended only to be a point of discussion for those people who may be
considering purchasing and/or using digital cameras for bird photography.
It should be realized that changes are occurring seemingly daily in this field
and therefore features and usability of digital cameras are changing also.
The types of digital cameras will change regularly as will the quality of image
produced.)
Birding-Aus is on the Web at
www.shc.melb.catholic.edu.au/home/birding/index.html
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