18101964
Description
Flashcards by Jaime Ruiz, updated more than 1 year ago
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Created by Jaime Ruiz
over 5 years ago
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| Question | Answer |
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Aberration
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Ts 167 (binary/octet-stream)
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A distortion of image quality or color rendition in a photographic image caused by optical limitations of the lens used for image capture. Aberrations commonly show up in the form of halation around high-contrast portions of the image, or "smearing" of color toward the edges of the frame. Aspheric lens surfaces and advanced lens coatings are often used in more expensive or complex lenses as a means of reducing aberrations. |
| Absolute resolution | Image resolution as expressed in horizontal and vertical pixel count (e.g., 1600 x 1200 pixels is the absolute resolution, and is also expressed as 2.1 megapixels (MP), having more than 2,000,000 pixels on its sensor). |
| AF Servo | Also known as Continuous Focus, AF Servo is maintained by partially pressing the camera's shutter release button, which enables you to maintain focus continuously on a moving subject as the subject moves within the frame. Shutter-response times are usually faster in AF Servo, since the subject is already in focus. |
| APS-C (APSC) | A term used to describe the size of the digital imaging sensors used in almost all compact DSLRs. The name is derived from the APS (Advanced Photo System) film format that was introduced in 1996 for the amateur point-and-shoot market. The APS format is about half the size (23.6 x 15.8mm) of a standard 35mm frame (24 x 36mm) and has a 1.5x magnification factor (multiply the focal length x 1.5) for determining the 35mm equivalent focal length of lenses used on APS-C format cameras. APS-C format DSLRs from Nikon, Pentax, Fujifilm, and Sony (Alpha) contain APS-C sized imaging sensors. Canon compact DSLRs, which include EOS Rebel-series DSLRs, contain APS-C format imaging sensors that are slightly smaller than competitive compact DSLRs (22.3 x 14.9mm, so the lens factor for these cameras would be 1.6x). Although it does further reduce the effective field of view of your lenses, they are slightly more telephoto than their 1.5x brethren. |
| Aspect Ratio | Aspect ratio refers to the shape, or format, of the image produced by a camera. The ratio is derived by dividing the width and height of the image by their common factor. The aspect ratio of a 35mm image (36 x 24mm) is found by dividing both numbers by their common factor: 12. So, if you divide each by 12, your resulting ratio will be 3:2. Most computer monitors and digital cameras have a 4:3 aspect ratio. Many digital cameras offer the option of switching between 4:3, 3:2, or 16:9. |
| AWB (Auto White Balance) | An in-camera function that automatically adjusts the chromatic balance of the scene to a neutral setting, regardless of the color characteristics of the ambient light source. Although AWB generally does an acceptable job of cleaning up the color balance of a scene, there are times when AWB should not be used. Examples of times you should avoid AWB are sunrise and sunset—such scenes would lose their warm qualities with the camera set to AWB. When capturing sunrises and sunsets, the camera should be set to Daylight to maintain the warm tonalities that make dawn and dusk so visually inviting. |
| Chromatic Aberration | Also known as color fringing, chromatic aberration occurs when the collective color wavelengths of an image fail to focus on a common plane. The results of chromatic aberration are most noticeable around the edges of high-contrast images, especially toward the edges of the frame. Chromatic aberration is most common on less expensive lenses, although even the best optics can occasionally display lower levels of chromatic aberration, under certain conditions. Another form of chromatic aberration is called "purple fringing," which comprises the purple streaks or halos that often appear within images produced by digital cameras. Purple fringing originates in the light refracted from the light-gathering micro lenses that cap the sensor's pixels. In backlit scenes, this form of purple fringing is commonly called "blooming." |
| Color Depth | The number of distinct colors that can be represented by a piece of hardware or software. Color depth is sometimes referred to as "bit" depth because it is directly related to the number of bits used for each pixel. A 24-bit digital camera, for example, has a color depth of 2 (2 bits of color) to the 24th power, resulting in a dynamic range of 16,777,216 colors. Similarly, an inexpensive 8-bit color monitor can only reproduce a total of 256 colors, which is far less than the expansive range of color contained in the digital image files captured by almost all consumer digital cameras. |
| CompactFlash Card (CF) | A popular flash memory device, which is available in a number of storage capacities. Unlike earlier mechanically driven MicroDrives, newer CF cards are solid state, quite stable, and are capable of operating under extreme environmental conditions. Once the dominant format for in-camera data storage, CF cards have receded from the spotlight as smaller SD/SDHC/SDXC memory cards have become the card of choice in ever-smaller digital cameras. |
| Compression | A method of reducing the size of a digital image file to free up the storage capacity of memory cards and hard drives. Compression technologies are distinguished from one another by whether or not they remove detail and color from the image. Lossless technologies compress image data without removing detail, while "lossy" technologies compress images by removing some detail. Joint Photographic Experts Group (JPEG) is a lossy compression format supported by JPEG, PDF and PostScript language file formats. Most video formats are also lossy formats. TIFF files are not and, as such, are far more stable than JPEGs and other lossy file formats. |
| Color Temperature | A linear scale for measuring the color of ambient light with warm (yellow) light measured in lower numbers and cool (blue) light measured in higher numbers. Measured in terms of "degrees Kelvin*," daylight (midday) is approximately 5600K, a candle is approximately 800K, an incandescent lamp is approximately 2800K, a photoflood lamp is 3200 to 3400K, and a midday blue sky is approximately 10,000K. |
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