显示标签为“penta prism”的博文。显示所有博文
显示标签为“penta prism”的博文。显示所有博文

2011年12月19日星期一

Anatomy of Optical Lens

The basic optical lense components of an SLR come in eight parts. This is the section of the camera where the images pass through from the front the camera to your eye. The eight basic components are the front-mount lens, reflex mirror, focal plane shutter, image sensor, focusing screen, condenser lens, the prism (also known as pentamirror) and the eyepiece.
Single Lens Reflex camera or popularly know by their acronym as SLR is a type of camera that uses mirror system called penta prism. This system allows the user or the photographer in this case, to capture image as how he exactly sees in the viewfinder. This is achieved through the help of automatic moving mirror system in the camera.Reflex Mirror - once the reflex mirror receives the image, it is then projected on a matte called focusing mirror.Front-mount Lens - this is where the image, in form of light, first comes in. It then reflects it to the mirror behind called reflex mirror. This lens can still be enhanced by attaching another lens to it. Those lenses come in different names. Others call it photographic lens, some call it objective lens or for those who want to shout out loud that they are indeed photographers call it photographic objective lens (a mouthful worth of name truly makes it sound more professional).
Condesing optical lense - after the image passed through the focusing mirror, it is then transferred to condensing lens. It helps concentrate light of the transferred image. Focal Plane Shutter - at the same time with focusing mirror, the same image travel beyond the reflex mirror as it moves upwards and to the focal plane shutter.Image Sensor - as soon as the focal plane shutter opens, the image will be directed to image sensors that translate the lights to electrical signal. Most image sensor in digital slr cameras are made of charge-coupled device (CCD) or complementary metal-oxide-semiconductor (CMOS) active-pixel sensor.
Eyepiece - the backside of the pentaprism is connected to the eyepiece and there is where you see the image focused in front of the lens.Optical penta pri - some slr's use roof pentaprism or penta-mirror to reflect the light to the eyepiece. In this process, the light that travels through the condensing lens passes to the bottom straight to the roof of the prism. Then the light is reflected to the front side then bounced horizontally to its back. Another prism design is called porro prism. A photographer can also use a right-angle finder which can be attached to the eyepiece that allows viewing like a waist-level finder
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2011年9月8日星期四

The Optical Lenses Used In Digital Camera

In order for the single lens reflex to work, mirrors are used within the camera to direct light from the lens to the back of the camera and the viewfinder. An SLR digital camera is one that uses a single-lens reflex and does not use film but stores the pictures as digital or image files.The first digital camera was made by Kodak in 1975, with the first SLR model created by Sony in 1981. The basics include a mirror that reflects light in a 90 degree angle from the optical lense to the view finder. This light is then reflected three times so the person can see the image properly. When the picture button is pressed the mirror swings in an upward motion which causes the aperture to become smaller. The shutter opens and then light touches the image sensor. A 2nd mirror will swing over the image sensor which will end the light exposure and the mirror swings back into place. In this period there is no image through the viewfinder, known as viewfinder blackout. This entire motion happens very quickly with SLR cameras, as this motion can occur as much as 10 times in a second.

The depth of field refers to the distance between the farthest and nearest object in the picture. These cameras also allow for accurate viewing of depth of field and the lenses can be interchanged. The reason digital SLR cameras are preferred by professionals are that the photographer has a very accurate preview of the actual picture that is being taken. The mirrors used in the camera can be either penta prismor penta-mirror. Entry level versions typically use a penta-mirror, which is a prism that has 5 sides. Instead of being made of glass the penta-mirror is made plastic which is less expensive and much lighter than pentaprism. The pentaprism is in the same shape as the penta-mirror but it is made of glass. When light passes into the prism it bounces off the back wall, changing light direction by 90 degrees.

The ability to change optical lense will depend on the camera maker and the type of lens. The lenses must have the same shape so that it fits into the lens mount on the camera. Many manufacturers use lenses that can fit in many cameras while some manufactures make lenses that are proprietary in which case will only fit in that manufactures camera. The proprietary nature of some SLR digital camera manufacturers would be one of the main reasons that once a photographer makes a choice in a particular camera he stays with that brand as all of their lens will only work with that brand.

WTS Photonics Co., Ltd provide our customers with the superior quality optics products and precision Laser Optics products ,serves a global markets including Laser, Electronics, elecommunication,Thermal Imaging, Infrared Sensor for Industrial, Medical and Scientific Research applications. We spacialize in  bandpass optical filters,laser line filters,Optical Lenses,meniscus lenses, beam splitters , sapphire windows, Mirrors, Filters,Precision Prisms, penta prisms, Quartz, MgF2, CaF2, Ge, Silicon etc..More information about our products pls link to our official website: www.wtsphotonics.com.