Photography Basics

List of Terms

Cost Factor: Continued

• Stabilized versus non-stabilized lens: Stabilized lenses will have two multi-position switches somewhere on the side of the lens. One "button" will be for stabilization on or off. The second button would be used for setting the stabilization mode. One setting is for general still photography, where the subject isn't moving and neither is the photographer. The other setting would be a tracking mode where stabilization is provided along the opposite axis to which the lens is moved to track a moving subject. For example, while tracking a deer running left to right, the lens stabilization works to minimize lens movement up and down. If tracking a subject moving up or down, the stabilization minimizes movement left and right. Trying to track a subject in any direction with the stabilization set to full stabilization (minimize movement in all directions), can be difficult to do smoothly. The lens tends to resist movement and then suddenly jumps in the direction you're trying to move it.
  • The best example I can provide is my own experience trying to track the International Space Station with full stabilization on. I find the station and start shooting. As I try to follow the station across the sky, I find I can't maintain smooth movement. Instead, I catch up with the station, take a few quick shots, then find the station getting ahead of me and then struggle to catch up again. No matter what I do, I can't simply keep the camera's center focus point on the station. I either get ahead of it of fall behind. It's actually amazing I ever get any good shots of it. Setting the stabilization switch/button to tracking mode makes the camera movement much smoother. Now if I could just make the auto-focus work...
• Sensor Types: You may have heard the terms 'full-frame', 'APS-H, and APS-C relating to the size of a camera's imaging sensor or imaging chip. The full-frame reference goes back to the days of film photography. Each frame of 35mm film was the same size. In digital photography, a full-frame sensor is an imaging surface equal in dimensions (width and height) to a 35mm film frame. APS-H sensors are smaller than full-frame sensors and essentially provide a 1.3x magnification factor of the lens mm rating. APS-C sensors come in two sizes providing a 1.5x or 1.6x magnification factor of the lens rating. Basically, a 200mm lens shot on a full-frame sensor provides a 200mm magnification factor; 4x what your eyes see. The same 200mm lens shot on an APS-H would provide a 260mm magnification factor; 5.2x what you "see." On the APS-C sensors, the same 200mm lens would provide an image magnification factor of 300mm (200x1.5) or 320mm (200x1.6) with everything else being equal.
• Benefits and drawbacks of sensor types: Full frame sensors tend to be much more expensive than the smaller APS-H and APS-C sensors. The same materials are used but less of the same material is needed for the smaller sensor sizes so they are cheaper. There's actually a lot more to it than that, but that is the basic difference and is easily explained. The issues of cramming the same number of megapixels onto the smaller sensors is more of a challenge than spreading them across the larger sensor surface, so the cost differential ratio is not a 1:1 comparison from one sensor size to another.
  • Full frame sensors tend to provide better quality images, smoother transitions between colors and details, and generally just look better overall. Digital noise levels (pixelation) tend to be much lower in full frame sensors than in the smaller sensors, and they also generally have better color reproduction or color 'bit' levels. 8-bit color is fewer colors than 10-bit color. These are binary representations of colors. 8-bit color is 255 color variations per primary color (255 shades of red, 255 shades of green, and 255 shades of blue.) These may be represented as RGB colors. Red, Yellow, and Blue are the primary "reflected" colors we all learned in school. But, in capturing and reproducing light and color in the digital world, those colors are RGB mixes. Your television monitor or computer screen uses RGB color.
  • Regardless of the sensor size, higher color-bit resolutions cost more than lower color-bit resolutions for the same sensor size.
    Related to the sensor size and color-bit resolution is the various sensors ability to employ higher ISOs to capture photos in dark shooting conditions. This is really where the full-frame sensors excel. Larger sensor generally produce much smoother or less grainy images at higher ISOs than their smaller counterparts at those same ISOs. A few sample images would be very helpful here for comparison.
• Sensor Capacity (megapixels): A camera's megapixel specification indicates the width and height, in pixels, of the camera's sensor. A sensor having 3000 pixels in horizontal resolution and 2000 pixels of vertical resolution, would be a 6-megapixel (6 million dots) sensor. That's a photograph that is 3000 dots wide and 2000 dots high on your screen or in print. Since these sensors tend to shoot natively in a 2x3 format, the 2000x3000 dots example is a simple example. So, what would be the resolution, width and height, of a 16 megapixel sensor? That would be approximately 3264x4896 pixels. While we increased the megapixl count more than 2.5 times, our imaging area or photo size only increased roughly only 1.6 times in each dimension. In order to double the height and width of the captured image, you would have to use a sensor that was 4x the megapixel capacity of the original. So, to double the height and width of a 6-megapixel image, you would have to shoot the same picture with a 24-megapixel sensor; resulting in a 4000x6000 pixel image.
• Can you tell the difference between doubling the image's dimensions and doubling the "square inches" of the final image? Doubling the dimensions is actually making the coverage area, say in square inches, four times larger because you are doubling both the height and the width. You aren't just doubling the "coverage" area. 4 by 6 is 24 squares. 8x6 is 48 squares or double the coverage area. But 8x12 is 96 squares (double the height and width) which is 4x the original 4x6.
• Auto-focus and manual focus: Pretty much without exception, if a lens has autofocus capability, it's going to be a lot more expensive than a manual focus only lens. There's simply a lot less hardware and software involved in a manual focus only lens. Unless you're shooting still life, I can't imagine using a manual focus lens. But I can imagine, and have shot, in manal focus mode in specific circumstances, such as a 1-5x macro lens that was manual focus only. Extremely dark areas or where the subject is in an area with a lot of high-contrast surroundings or branches or wires running in front of or behind the subject. Each of these can cause problems for auto-focus systems.

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