Monday, March 31, 2014

Connecting to a Computer

Connecting directly to a computer for data transfer is available with many digital cameras; this creates the ability for the photographer to choose only the best images for printing. It also allows the photographer to print and store hundreds of images, which would require many rolls of film and necessitate extensive storage for negatives.

These are some of the methods of connecting:

* Early in production they used a PC (personal computer) serial port.

* USB is the most widely used method now; a universal serial bus is now a standard interface device.

* FireWire ports; this is a copyrighted name of Apple Inc for the IEEE 1394 interface.

* USB PTP (picture transfer protocol) may be used as a mode of connection rather than the USB MSC (mass storage device); some computers offer both methods.

* Some cameras use wireless connections.

* A card reader is a standard alternative. It is capable of reading many different types of storage media, and it allows high speed transfer of data.

A card reader also eliminates draining the battery in the camera during the process of downloading data. The power is taken from the USB port, not the camera.  This can be inconvenient if only one reader card is used to directly access the images to several storage media, which requires moving the card back and forth between media.

Many cameras are now set up to transfer data directly to the printer without the use of a computer. There are several devices that have digital cameras built in, due to limited storage and with the emphasis on convenience; the quality of the images is usually poor, cell phones are the most common of these items. PDAs, laptops and Blackberries are others in this class; even some camcorders have digital cameras built in.

Thursday, March 13, 2014

Compromises Made by Your Digital Camera

The means your camera uses to take images and translate them from the image sensor to the computer or printer may not be hindered by the compromises it makes during the process.  You will only know this when the photos are being viewed at the time of transfer.

Storage is one of these compromises; digital images take a great deal of space for storage. They need to be managed in a way that ensures enough images can be stored before they need to be downloaded from the camera.

Cameras use different levels of compression to downsize the images for storing them in memory. JPEG is the most widely used standard, it removes information that can't be seen by the human eye anyway. The higher the level of compression, the more information is deleted.

At the higher compression setting, blocks start to appear in the images. This begins to degrade the image quality, making the resulting file size extremely small.  If quality is the most important consideration, avoid JPEG compression. 

The mid- to high-end digital cameras offer different forms of compression, which don't delete any information, by using mathematical algorithms. They compress the file and save it either in TIFF format or as RAW files, which contain only the information the sensor captured with no in camera processing.

Larger file sizes are the result of this lossless file compression format. However, the higher image quality and post processing flexibility makes up for the loss in image storage space.

Another compromise made in digital cameras is the in-camera processing; these create predefined results. Some cameras have sharpening filters which restore the contrast that is lost in edge details when the image goes through the various optical filters.

This process of sharpening in the camera reduces the ability to sharpen the image once it has been downloaded to the computer. Oversharpening can create unnatural and harsh edges and may even cause shifts in color.