Lens Elements and Groups
When shopping for camera gear, you've undoubtedly encountered listings detailing how many "elements" and "groups" certain lenses have.
Lens elements
Techniques Glossary Lens elements
The individual pieces of glass that form the overall optical construction.
LENS ELEMENTS & IMAGE QUALITY
All but the simplest cameras contain lenses which are actually comprised of several "lens elements.
Lens element. A single piece of optical glass that acts as a lens or as part of a lens.
lens element's surfaces:
1. ground, 2. polished, 3. coated
Elements Edit ...
Lens elements.
5. Fine-tuning the Light
With a lens on the front of the camera, you can choose between having an image that's in focus or one that's out of focus but there really is no in between.
A lens element is a single piece of shaped glass or crystal. Camera lenses these days contain anywhere from 4 lens elements and up. They are frequently arranged in optical groups within the barrel.
The lens elements are made of transparent materials. Glass is the most widely used material due to its good optical properties and resistance to scratching. Sometimes lenses are made of materials such as quartz or fluorite.
A layer or multiple layers of thin anti-reflective materials applied to the surface of lens elements to reduce light reflection (flare) and increase the amount of transmitted light.
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Sometimes applied to an iris diaphragm whose blades operate between lens elements. SHUTTER, FOCAL-PLANE-A shutter located near the focal plane and consisting of a curtain with a slot that is pulled across the focal plane to make the exposure.
However, its not always easy to tell where the lens elements are. Check with your housing manufacturer for the best alignment.
You can use ports made out of optical glass or acrylic.
The camera moves one way, and the prism or lens element moves the other. This is the most effective method, but also the most expensive.
Digital image stabilization shifts the image on the sensor to compensate for motion.
However, unlike other manufacturers who indiscriminately apply the same number of coatings to each and every lens element regardless of its type or the glass used, ...
Image Stabilization in Lens Elements.
Nikon is using similar technology to compensate for unintentional camera movement.
Schneider lenses of particular note include the Super-Symmar XL series with their aspherical lens elements. The 110mm f/5.6 Super-Symmar XL lens is extremely popular, and often listed as a "favorite" lens in many a photographer's arsenal.
In the construction of the modern complex lens every lens element is carefully positioned and set in a fixed point.
If you need to clean a DSLR lens, I suggest you start by using the blower first to blow all loose dust or grit off both the exposed face of the front lens element and the exposed face of the back lens element if it's easy to reach.
I suspect that this is due to the lack of an anti-reflection coating on the rear lens element. I think this results in light reflecting off the sensor, onto the rear lens element and back to the sensor.
However, a teleconverter does contain lens elements. A teleconvertor increases the focal length of a lens, but it does not change the minimum focus distance. This results in an increase in magnification.
ASPHERIC (ASPHERICAL) LENS - A lens element that changes shape across its surface as opposed to one having a smooth continuous arc.
Three UD (Ultra-low Dispersion) glass lens elements correct chromatic aberrations and floating elements ensure sharp definition at all subject distance. A ring USM provides silent AF and full-time manual focusing.
It has 2 clear lens elements; the front lens is the cornea which is fixed, and the flexible lens just behind the pupil which changes shape as we focus. There is a fluid filled cavity between the cornea and the lens.
Reflected light; from lens elements, sun, metal, etc. Appears as non-uniform haze or bright spots on the film or digital frame, often taking the shape of the aperture, generally caused from shooting towards the light source.
12x optical zoom lens with USM and UD lens element
Optical Image Stabilizer
6.0 Megapixel CCD
2.0' Vari-angle LCD
30fps VGA movies with stereo sound and Photo in Movie feature
DIGIC II, iSAPS and Flexizone AF/AE for fast, precise results and 2.
The new lens has been engineered for the ultimate in optical performance through the use of two fluorite lens elements for improved quality and reduced chromatic aberration.
Glass with ED properties indicating special rare earth glass or special formulated glass that limiting or correcting of light rays passing through the lens elements to achieve all spectrum of colours to falls on the same plane of focus - especially ...
Tilt-shift lenses are designed to shift on a rotating plane, allowing the lens element to slide left/right or up/down. There's a metal clip that releases tension, so the lens can be rotated to alter its position by 90 degrees.
A: A centering defect originates in a misaligned lens element or lens group. The result is a blurry corner, an off-coplanar projection (symmetrical blur) or object edge shadows.
Telephoto Lens A specific type of long-focus lens in which a positive (converging) lens element is placed in front of the diaphragm and a negative (diverging) lens element is placed at the rear of the diaphragm.
When VR/IS is on, the lens element(s) or image sensor move so that the image stays in place when projected onto the sensor. As a result, camera motion is less likely to affect the sharpness of your photographs.
Also known as a reverse or inverted telephoto, this lens design has a diverging lens element positioned in front of the aperture and a converging element positioned at the rear.
Retrofocus - type of lens design with a negative lens element positioned in front of the diaphragm and a positive lens element positioned at the rear of the diaphragm.
Filter: A subsidiary lens element [usually of circular glass] that fits onto the front of lenses, to enhance or change their optical properties, and therefore the image being taken.
Cheaper lenses, especially those that come built into a compact camera, can often contain plastic lens elements.
Cause: Front and/or rear lens elements dirty. Solution: Clean with lens tissue and cleaning fluid. Use one drop of cleaning fluid on a tissue and clean lens in a circular motion starting from the center.
In a zoom lens, you can move different lens elements back and forth. By changing the distance between particular lenses, you can adjust the magnification power -- the focal length -- of the lens as a whole.
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Use the cloth to clean the camera's body and the brush to flick off dust on the outer lens element. The rubber squeeze bulb can be used to clean the memory or battery compartments.
The reflected light from lens elements that appears as a non-uniform haze or as bright spots on the film. This usually happens when a bright light directly enters the lens.
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Zoom lenses contain more lens elements than a fixed-focal length or prime lens, and therefore aren't quite as sharp. Naturally, the angle of view decreases as you increase the focal length and magnify the image.
An overall decrease in contrast caused by light being reflected off, instead of transmitted through, a lens surface; controllable through the use of multilayer coating of individual lens elements in a lens; ...
Does anyone have any experience cleaning the inside of the lens elements?
-Effective aperture - diameter of the bundle of light rays striking the first lens element that actually pass through the lens at any given diaphragm setting.
-EIS - Electronic Image Stabilizer. A feature that minimizes effect of camera shake.
Fig. 1: For the sake of simplicity, this diagram shows only one lens element. In actuality, an interchangeable VR lens has many lens elements.
Focusing
Adjusting the position of the lens elements to bring the image into focus, i.e. so that it is clear and sharp.
Full automatic
In this mode, the camera not only controls the aperture and shutter but all other settings (e.g. flash).
OIS uses a spinning gyroscope and a lens element to counteract camera movement and handshake at longer focal lengths and lower shutter speeds.
Photo 1 shows the result of leaving a drop of water on the rear lens element, and I have 35 more just like it (see the hexagonal dark spot in the photo's upper left, just above the lobster's antennae).
Contemporary lenses are invariably of the compund type. That is, they are made with multiple lens elements, combining to correct image aberrations. This is necessary because light is not single, unified source, but has different color and wavelengths.
It does this by moving lens elements to change the focal length of the camera's lens. Some of the best optical zooms can be as much as 10-to-1 (10x). Most medium priced digital cameras will have a zoom in the 6-to-1 (6x) or 3-to-1 (3x) range.
They typically are focused by extension (simple mechanism), don't require aspheric elements (simple lens element shapes), they don't require elements made of glass with anomalous dispersion (simple materials), ...
This could cause condensation on lens elements or ports when you enter the cooler water, or worse a flood from a popped "0" ring seal. Keep your equipment cool by covering it with a towel when you bring it on deck for the dive.
[Note that since most camera lenses are made up of more than one lens elements, the definition "middle of the lens' is adjusted slightly.] ...
There are several other terms to take into consideration when buying a digital camera lens to make sure you are making the best purchase. If your lens utilizes aspheric lens elements, ...
There is some sort of mechanism in the camera that moves the lens elements to bring the image into focus. Some cameras are quite good at this and some have difficulty in low light situations.
Optical Image Stabilization (OIS) - Most commonly found in higher-end dSLR telephoto and tele-zoom lenses. OIS uses a spinning gyroscope and a lens element to counteract camera movement and handshake at longer focal lengths and lower shutter ...
Image stabilization. A technology that compensates for camera shake, usually by adjusting the position of the camera sensor or lens elements in response to movements of the camera.
Store cameras and lenses in padded cases and, in very damp environments, place the camera in a plastic bag or in underwater housing. Be sure, too, that the front lens element or filter is kept clean.
A major flaw with the G series: the need for lens barrel replacements every 6-12 months due to debris infiltration between the lens elements.
Extension tubes are hollow tubes of varying lengths that increase the focal distance of the lens by moving the lens elements further from the film or sensor. Extension tubes on current cameras generally disables the autofocus feature.
With two extra-low dispersion glass elements and three aspherical lens elements, the lens delivers high-resolution, high-contrast images while minimising chromatic aberration. Ideally suited for use on Nikon DX-format and FX-format cameras.
The dual element ones are corrected to prevent this from happening. Extension tubes create distance between the camera body and rear lens element allowing you to focus the lens closer to your subject than it would without it.
 See also: Element, Lens, Camera, Image, Light
  
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