DPOF-pronounced “di pof” – an abbreviation of Digital Print Order Format – a format to record information about personnel camera, computer or other device creation / image processing to automatically print to the printer (supports DPOF), and photo labs.
Also used to represent images on websites, in presentations, when we send by fax transmission on networks of cellular phones and so
without involving the computer.
For these purposes in a specific folder on the memory card are text files with data.
The data contain information on what frame you want to print, how many copies of what information should be typed into the picture, which frames to print on one sheet, size of print, etc.
Typically, the data are entered from the menu in the camera view, or from computer graphics applications.
Digital zoom
On it you may already have heard many times, especially with regard to digital cameras with a lens unregulated.
Some manufacturers are known for their inscription “6x zoom” on the camera, while the real camera has 3x optical zoom, and can additionally involve 2x digital zoom.
Optical zoom lens design is provided and shows how many times the image is increased when changing the focal length of the lens from minimum to maximum.
Depending on which side of the counter you are, the digital zoom can be considered as a useful addition to the cameras with a small optical zoom or a pathetic marketing ploy to sell cameras with limited zoom.
In fact, the digital zoom is simply cutting out the central part of the frame.
Some manufacturers cut the central portion of the frame and not even stretch the image to full frame camera.
This is not digital zoom, but simply cut.
Another, slightly more complicated implementation of the digital zoom is a cut of the same center of the frame and its interpolation to the full (native) resolution of the camera.
Tips on choosing the digital zoom
Digital zoom can be useful when viewing images on a monitor with lower resolution than the resolution photomatrix camera.
For example, the use of digital zoom with XGA (1024 x 768) resolution for a 2-megapixel digital camera (1600 x 1200) will work as follows:
XGA 1024 x 768 without the digital zoom – 1600 x 1200 image is compressed to 1024 x 768
XGA 1024 x 768, 1.
25x digital zoom – 1280 x 960 segment is compressed to 1024 x 768
XGA 1024 x 768, 1.
6x digital zoom – 1024 x 768 fragment
XGA 1024 x 768, 2.
0x digital zoom – 800 x 600 piece stretched to 1024 x 768 *
XGA 1024 x 768, 2.
5x digital zoom – 640 x 480 piece stretched to 1024 x 768 *
When using the digital zoom further details in the image does not appear.
Focal length – focal length
Focal length – is one of the most important characteristics of the camera lens, which is usually indicated on the lens and is measured in millimeters.
To be more precise, it provides a back focal distance, which is actually of interest.
This is the distance from the posterior cardinal point of the lens (in our case it is the nodal point: a beam of light passing through the anterior anchor point of the lens comes out through the rear anchor point at the same angle) to back focus, which converge parallel to the axis of the lens the light rays.
Focal length and size of the sensor determines the camera angle.
In lenses with variable focal length (zoom), the focal length range lens.
Do digital cameras are usually fairly small number, eg, 6 -15 mm.
In the traditional 35 mm photography running lenses have focal length of 28 mm, 50 mm, 200 mm and so
Censor (photomatrix) digital cameras are usually much smaller than 35 mm frame, for this reason, the camera lens can be smaller.
sensor size in different cells are different, it is usually stated as an equivalent 35 mm camera lens focal length, which allows sravnivatvozmozhnosti chambers between them.
For example, the camera lens Canon PowerShot Pro 70 is marked 6 -15 mm, although the zoom lens is always spoken of as the 28 – 72 mm, etc.
in order to operate more familiar figures real focal length is multiplied by 4.66.
35 mm equivalent
All manufacturers of digital cameras point “of 35 mm an equivalent” focal length, simply because it is already familiar to users, and they imagine that can shoot 28 mm lens, and that 50 mm.
Here are the focal lengths of normal lenses:
less than 20 mm super wide-angle =
24 mm – 35 mm wide-angle =
50 mm = normal, viewing angle as in the human eye (46 °)
80 mm – 300 mm = long-focus (telephoto, narrow-angle)
300 mm = superdlinnofokusny
The increase in focal length leads to a greater increase in the image and reduce the prospects.
Optical zoom
Also you can find on the lens inscription «ZOOM», for example, 2 x zoom.
It has long been labeled the camera lens.
Like them, this number indicates how many times the maximum focal length of the lens more than the minimum, which roughly corresponds to an increase in the size of the object in the picture.
For example, the image of a man standing in front of you can take half of the frame vertically with 35 mm focus lens, but if you increase (zoom in – zoom) focal length of 70 mm (2 x 35 mm), the image will take the entire height of the frame.
The drawback of some digital cameras is the barrel (barrel) distortion when shooting with a small focal length, but the software in the same Photoshop, this can be corrected.
Exposure / Exposure / EV
Exhibition called really set the camera settings (aperture, shutter speed) and the photosensitive element (sensitivity) for photography.
Each exhibit is suitable for your shooting conditions and shooting conditions can be evaluated using the light-sensitive device – meter.
The output of this device there is a certain size – EV (Exposure Value).
This combination of sensitivity photomatrix (or film), aperture and shutter speed.
For example, exposure settings can be ISO 100, f / 2.
8, 1/60sek and these parameters can be used when the measured exposure is 9EV.
In fully automatic mode (and this regime is now in all chambers), the camera itself will calculate these values for you, measuring the magnitude of the required exposure, some of today’s cameras have manual shooting modes, where you can set the aperture (aperture priority) or exposure (shutter priority ) and even photomatrix sensitivity and other parameters will be calculated, the camera automatically, again based on the measured value of EV.
Thus, for different lighting conditions (different values of the EV), the camera calculates the shutter speed and aperture necessary for normal illumination of the photosensitive element.
The following table represents the relationship of shutter speed and aperture of the EV at ISO 100.
Expositional value can be calculated by the following formula:
EV = log2 (diafragma2 x (1/vyderzhka) x (ISO chuvstvitelnost/100))
Auto exposure – exposure compensation
The team can change the calculated camera exposure.
Normal range of correction from -2 to +2 EV in increments of 0,3 EV.
To increase the amount of light falling on the photosensitive element of the camera, it is necessary to apply a positive correction.
For example, if your camera has defined the parameters shooting at 1 / 60 sec F5.
6 (11EV), and you set the exposure correction +0,7 EV snapshot will be made with an exposure 1 / 40 sec F5.
6 (10,3 EV).