Depth of
field is the area of the image that appears in focus from foreground to background
and is determined by a combination of the opening of the aperture and the focal length of the lens. A small aperture setting results in greater depth of field.
Controlling depth of field is one of the easiest ways for a photographer to
compose the image.
information on digital camera, dslr, lens, photography tutorials, tips
Friday, September 21, 2012
Wednesday, September 19, 2012
Understanding F-Stop and Lens Speed
The
photographer adjusts the opening of the aperture by setting the f-stop. An
f-stop is a ratio of the focal length of the lens to the diameter of the
opening of the aperture. For example, a 50 mm lens with an aperture opened up
to a diameter of 12.5 mm results in an f-stop of f4 (50 ÷ 12.5 = 4).
Labels:
aperture,
f-stop,
fast lens,
focal length,
lens speed,
photography
Tuesday, September 18, 2012
Aperture
The
aperture is the opening in the lens (created by an adjustable iris or
diaphragm) that allows light to pass through. The exposure of the image is
determined by the combination of shutter speed and the opening of the aperture.
The larger the aperture, the more light is allowed to pass through the lens.
The aperture is measured in f-stops, and each stop represents a factor of two
in the amount of light admitted. The aperture setting (f-stop), combined with
the focal length of the lens, determines the depth of field of
an image. For more information on depth of field.
Labels:
aperture,
depth of field.,
exposure,
f-stop,
shutter speed
Sunday, September 16, 2012
Understanding Digital Zoom
The digital zoom feature offered by some
camera models does not really zoom in closer to the subject. Digital zoom crops
into the center area of the captured frame, effectively enlarging the pixels.
This results in a picture with a lower overall image quality. If you don’t have
a telephoto or optical zoom lens and you want a close-up, physically move
closer to the subject, if you can.
Thursday, September 13, 2012
Understanding Lens Multiplication with DSLRs
Most interchangeable lenses were
originally created and rated for the 35 mm film plane of traditional SLRs. If
you compare the area of a 35 mm film plane with the area of most digital image
sensors’ image planes, you’ll see that the area of most digital image sensors
is a bit smaller. The focal length of a lens changes when it is put on a DSLR
with a digital image sensor smaller than 35 mm. This smaller image plane effectively
increases the focal length of the lens because more of the image circle coming
out of the lens is cropped. For example, if you put a 100 mm lens on a DSLR that
has a 24 mm digital image sensor, the focal length of the lens is multiplied by
a factor of approximately 1.3. A 100 mm lens with a 1.3x multiplication factor
effectively becomes a 130 mm lens (100 mm multiplied by 1.3). Another reason to
take lens multiplication into account is that shooting wide-angle images
becomes increasingly difficult when using cameras with smaller digital image sensors.
For example, if your digital image sensor is 24 mm, you require a lens with a focal
length less than 24 mm to achieve a wide-angle view. Check your camera specifications
for the size of your digital image sensor.
Labels:
35mm film,
dslr,
focal length,
image plane,
image sensor,
lens,
lens multiplication,
slr
Camera Components and Concepts - Lens
The basic components of a DSLR are
described below. (Most of the components in a rangefinder are also found in a
DSLR.)
Lens, Aperture, Shutter, Digital image sensor,
Memory card, External flash
Lens
A lens is a series of sophisticated
elements, usually glass, constructed to refract and focus the reflective light
from a scene at a specific point—the digital image sensor.
Wednesday, September 12, 2012
Digital Point-and-Shoot
This is a lightweight digital camera, aptly named after the two steps required of the photographer to capture an image. Basically, point-and-shoot cameras require pointing the camera and taking the picture without manually adjusting settings such as the aperture, shutter speed, focus, and other settings that professional photographers routinely set on more sophisticated cameras.
Digital Single-Lens Reflex (DSLR)
This camera is named for the reflexing mirror that allows you to frame the image through the lens prior to capturing the image. As light passes through the DSLR camera’s lens, it falls onto a reflexing mirror and then passes through a prism to the viewfinder. The viewfinder image corresponds to the actual image area. When the picture is taken, the mirror reflexes, or moves up and out of the way, allowing the open shutter to expose the digital image sensor, which captures the image. Most features on a DSLR are adjustable, allowing for greater control over the captured image. Most DSLR cameras also allow the use of interchangeable lenses, meaning you can swap lenses of different focal lengths on the same camera body.
My technorati claim token : G73GM29ETVFG
My technorati claim token : G73GM29ETVFG
Subscribe to:
Posts (Atom)