High Quality Content by WIKIPEDIA articles A parfocal lens is a lens that stays in focus when magnification/focal length is changed. There is inevitably some amount of focus error, but small enough to be considered insignificant.Zoom lenses (sometimes referred to as true zoom) are ideally parfocal in that focus is maintained as the lens is zoomed (focal length and magnification changed), which not only is convenient, but also has the advantage of allowing more accurate focusing at maximum focal length and then zooming back to a shorter focal length to compose the image. However, not all socalled zoom lenses are actually parfocal. Author: Surhone, Lambert M./ Tennoe, Mariam T./ Henssonow, Susan F. Binding Type: Paperback Number of Pages: 92 Publication Date: 2010/09/29 Language: English Dimensions: 5.98 x 9.01 x 0.22 inches
- This adapter allows you to mount MD lens on Nikon mount camera body - It is also perfectly compatible with all Nikon you have to manually control the lens aperture and focusing - It allows the lens to focus to infinity - Precision optics and metal construction
The SteadyStar AO Guider can easily make several tracking corrections in one second without lugging the weight and inertia of the whole telescope. Rather than move all that weight, the SteadyStar AO Guider moves a small on-board lens, allowing for quick and precise movements several times faster than any traditional autoguider could ever hope to correct. This refractive correction, while different than the adaptive optics used in professional observatories, is capable of making extremely fast movements to overcome even the most severe tracking errors. The SteadyStar AO Guider is capable of correcting motion more than 40 times per second, depending on guide star brightness and computer speed. This means you will overcome your mount's periodic error, wind, and even compensate for some of the negative effects of turbulent seeing conditions. Quite simply, the SteadyStar is the fastest AO Guider used for amateur astrophotography on the market today!
Long Distance Laser Designator ND3X40. Green laser technology. 40mm lens. Illuminate a target at up to 400 yards. Oring seals keep water dust and dirt out. Adjustable bean (Rotary Optical Beam Collimator) allows quick adjustment of beam diameter and intensity Nitrogen charged to prevent lens from fogging. Includes scope mount (1 inch tube) with windage and elevation adjustments Weaver mount with dual size mounts (3/8 inch and 5/8 inch) Tripod mount carrying case momentary. Pressure switch and two Lithium CR123A batteries.
Fitting like a glove and ready to lead you into the fray, the Spy Optics Logan Sunglasses feature a sleek, dense propionate finish that is all business. With wraparound styling, these baby's go aerodynamic on a straight line cliff shot, bike trail bender, or during motor assisted access. An 8-base Arch lens maintains clear vision with a natural eye curved designed, while a gnarly tough and light Grilamid frame keeps you floating like a butterfly, so you wont get stung like a bee after a mega jump or anticipated crash landing. A built-in hinge system gives cool styling and a head hugging fit. Give 'em the love.
FM Optics 1X Mini Micro Red Dot Sight for lightning fast performance targeting SAVE BIG A supercompact adjustablebrightness Red Dot Sight for precision aiming in a hurry It s quality made a real value to help your gun rock out: Fully coated optics; Red dot reticle with 11 brightness settings for pointandshoot sighting in any conditions; 1X view no magnification with unlimited eye relief; Integral mount fits Weaver style and Picatinny rails; 1 M.O.A. windage / elevation adjustment; Water shock and fogproof; Comes with lens caps. 30 mm tube. Approx. 2 1/2 long 3 ozs.
Rokinon 650-1300 mm lens is perfect for professional and amateur photographersTelephoto manual camera lens is great for wildlife or nature photographyHigh definition optics produce sharper, more intense pictures Camera lens mounts to all Nikon SLR and digital SLR cameras with the included t-mount adapterSimply attach the included t-mount adapter to your camera and then attach the lens to the adapterBuilt-in, rotating tripod mount has been placed to provide optimum balance and stability on your tripod or monopodFocal length lock can be utilized to maintain a desired magnification Multicoated optics and integrated lens hood combine to maintain maximum contrast with reduced glare and reflections while its fitted case further enhances the value of this versatile zoom Zoom type: push/pull Minimum focus distance: 5 meters Aperture range: F/8.0 - 16.0Weight: 70.6 ounces (2000 grams) Filter size: 95 mm Includes lens hood, front and rear lens protection caps, padded pouch with shoulder strap and an instruction manual Dimensions: 18.5 inches long x 4.1 inches deep
The Rokinon 500mm f/8.0 Multi-Coated Mirror Lens is incredibly powerful. It's an excellent addition to any photographer's collection. This lens is a high-quality, computer designed product that incorporates the merits of both reflex optics and refraction optics. This combination provides the user with an extremely sharp picture with minimum color abberation. With its tremendous power, this lens is ideally suited for wildlife and sports photography. Multi-coated high definition optics and an integrated lens hood combine to maintain maximum contrast with reduced glare and reflections. It produces sharper, more intense pictures. Take incredibly close shots from long range distances. While this lens is designed for high definition telephoto photography, it is also one of the most affordable precision optics available, which allows anyone on any budget to enjoy shooting crisp, clear pictures. Aluminum alloy construction provides for a lightweight and rugged design that includes a rotating tripod mount, for balance and stability when mounted on a tripod or monopod. Comes in a beautiful Diamond Black body finish.
The Rokinon 500mm f/8.0 Multi-Coated Telephoto Lens is incredibly powerful. It's an excellent addition to any photographer's collection. This lens is a high-quality, computer designed product that incorporates the merits of both reflex optics and refraction optics. This combination provides the user with an extremely sharp picture with minimum color abberation. With its tremendous power, this lens is ideally suited for wildlife and sports photography. Multi-coated high definition optics and an integrated lens hood combine to maintain maximum contrast with reduced glare and reflections. It produces sharper, more intense pictures. Take incredibly close shots from long range distances. While this lens is designed for high definition telephoto photography, it is also one of the most affordable precision optics available, which allows anyone on any budget to enjoy shooting crisp, clear pictures. Aluminum alloy construction provides for a lightweight and rugged design that includes a rotating tripod mount, for balance and stability when mounted on a tripod or monopod. Comes in a beautiful Diamond Black body finish.
The Carson StarMapLight Red-LED Flashlight SL-1 is a red LED flashlight for low-light use. This Carson Flashlight is great for astronomy, photographic darkrooms, or reading theater programs without disturbing others...
The Donegan OptiVISOR is a hands-free, headband binocular magnifier that has optical glass lenses that are ground and polished into prismatic lenses for quality and clarity, and is available in multiple dioptric strengths (indicated by the number in the model) which provide specific magnification power (X) at specific focal lengths, or distance from object...
Optical glass binocular magnification in a headset made of lightweight, durable, impact-resistant material. Headband is easily adjustable to fit any size. Can be tilted up when not needed. Wear with or without glasses.
The Celestron(r) 400x Laboratory Biological Microscope comes with many scientific essentials such as a diaphragm and a condenser. Its efficient charm comes in its power and precision, with 3 different objective lenses and a monocular, adjustable head that rotates from 0 to 60 degrees for comfortable viewing.
This tried-and-true refractor goes the extra distance in introducing the novice to the wonders of the night sky. The Observer 70 features a 70mm fully anti-reflection coated achromatic objective lens, which provides 36% more light-gathering ability than a 60mm...
True HD video optimized for Microsoft LyncFull 1080p HD sensorAuto focusTrueColor technology for bright and colorful videoClearFrame technology for smooth detailed video
True 2.0MP sensorRazor-sharp images from a Carl Zeiss optics glass lensIntelligently adjusts to produce the best possible image with RightLight 2 technology8MP still-image capture (with software enhancement) RightSound technology provides clear audio without background noiseLogitech Video Effects allows user to choose from a variety of digital accessories to enhance or alter their lookMulti-person intelligent face-trackingHigh-speed USB 2...
Enjoy unparalleled performance when scanning negatives, slides or prints, with the Epson Perfection V750-M Pro, the first flatbed scanner with groundbreaking 6,400 dpi resolution and unique fluid mount capabilities for photo studio applications...
The 77mm Multi-Coated UVA Haze #010 Filter Ultraviolet light, which manifests itself in photographs as reduced clarity and the appearance of haze, is blocked by the UV 010. Ultraviolet light is invisible to the eye and is strong in mountainous and coastal areas with very clear air...
The Bushnell 8x21 PowerView FRP compact binoculars combine contemporary styling and design with traditional Bushnell quality and durability. They are easy to use and economical and feature general-purpose roof prisms...
Absorbs the ultraviolet rays which often makes outdoor photographs hazy and indistinct. Multi-purpose fine-weather filter for color as well as black and white films
This Tutorial Text is intended for practitioners in the fields of optical engineering and optomechanical design. It provides a comprehensive examination of the different ways in which lenses typically are mounted in optical instruments, of the advantages and disadvantages of various mounting arrangements, and of the analytical tools that can be used to evaluate and compare different designs...
This Tutorial Text examines the various ways in which prisms and small mirrors typically are designed and mounted in optical instruments. It provides analytical tools for evaluating different designs and discusses advantages and disadvantages of various techniques...
.3x Century Optics "Intermediate Lens" Fisheye Footage
I can get a free Celestron PowerSeek 50mm Telescope on mycokerewards. Is it any good?
The info says,
"This high-tech telescope features an altazimuth mount, 3x Barlow lens, coated optics, 2" optical refractor, and a 600mm focal length. It's also equipped with a 5 x 24 straight finderscope, and 20mm, 12mm, and 4mm eyepieces. The included aluminum tripod supports the telescope, as well as an accessory tray."
I have never owned or shopped for a telescope, and have no idea what most of this stuff means.
The points they're asking for is about 467 20oz-ers worth, or 140 12-packs. I already drank the soda, which I would've bought anyway, so technically the 'prize' is free.
It can be purchased for $50. I didn't need to take a close look to know that it's a toy. Not a real tool. My binoculars are better than this scope. It is lightweight and will jiggle. It is too small to show deep sky objects. You will not be happy with it. Buy some 50mm binoculars instead, you'll love scanning the sky with them, and, when you end up with a real telescope, you'll still enjoy the binocs!
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