The Computar 12.5mm/1.3s in that auction are auto-iris, and possibly even CS-mount. ages ago (permalink)

The laser diode is a light emitting diode that uses an optical cavity to amplify the light emitted from the energy band gap that exists in semiconductors.  (See Figure 6.)  They can be tuned to different wavelengths by varying the applied current, temperature or magnetic field.

I suspect they'll have significant vignetting, but any new lens in the wide range is much needed and much welcomed. I have a couple of the Fujinon-TV CF12.5A (1.4/12.5mm), which I believe provide the best coverage of the m4/3 sensor among the 12mm lenses. I've been intending to make this modification to one of them: www.forums.getdpi.com/forum/showthread.php?p=274374 I've just put it on hold because I'm looking for an engineer to machine a couple items (specifically the outer hood needs to be re-constructed), and I've been enjoying the un-modified one. I also have the Cosmicar 12.5mm/1.3, which is also great but has a bit more vignetting than the Fujinon. ages ago (permalink)

How dolaserswork

Thanks. As far as I can see, the Fujinon price is order of ~$200 in some places! I guess it is a hot item. Let me fiddle around a bit more to see if I can find something I want to try. Here is interesting list: forum.getdpi.com/forum/showthread.php?t=17470 ages ago (permalink)

It looked weird to me that is indeed why I asked. Thanks for the pointer and correction! ages ago (permalink)

by D Helde · 2007 · Cited by 29 — Point Spread Function is a method of evaluation the spatial resolution of an imaging system. It is also a measure of the spread of a single point of light.

What are lasers used forin everyday life

Of course, there's always the option of using a wide converter. ages ago (permalink)

Red Laser Pointers · 2 in 1 USB Rechargeable Mini Red Laser Pointer Pen With White LED Pet Light · 3 Packs Laser Pointer Pen Red Blue Green 900Mile Light ...

Laser acronym

The word laser is an acronym for Light Amplification by Stimulated Emission of Radiation.  Lasers are used as research aides in many departments at Princeton University.

In this document, the word laser will be limited to electromagnetic radiation-emitting devices using light amplification by stimulated emission of radiation at wavelengths from 180 nanometers to 1 millimeter.  The electromagnetic spectrum includes energy ranging from gamma rays to electricity.  Figure 1 illustrates the total electromagnetic spectrum and wavelengths of the various regions.

Hi, Sometimes I crave for a cheap "wide-angle" lens for my EP2. I have just seen this announcement: www.43rumors.com/slrmagic-lens-update-with-new-12mm-fast-... I do not particularly like what SLRMagic is doing with these lenses which appear to be adaptations of existing c-mount lenses but the mention Avenir CCTV lens seems interesting. I realize it won't provide a full coverage and I will end up with some vignetting. If I accept to live with that, how much of the FOV am I losing? does anyone have sample shots to share? Any favorite 12mm C-mount lenses? 2:57AM, 29 December 2010 PST (permalink)

HDCVI is an over-coaxial cable video standard that enables long-distance HD video transmission over a wide range of application scenarios at a friendly cost.

Whatis laser in Physics

In contrast, the output of a laser, as shown in Figure 3, has a very small divergence and can maintain high beam intensities over long ranges.  Thus, relatively low power lasers are able to project more energy at a single wavelength within a narrow beam than can be obtained from much more powerful conventional light sources.

Essential equipment for UV curing adhesives. High performance technologies, UV bulb or LED. Various devices adapted to your applications.

i received a fujinon 12.5mm, but of course my adapter couldn't focus to infinity... i ordered the same adapter as maxnk has spoken of in his posts. i also ordered the fujian 35mm and just received it. the adapter works with my fujinon (needs a shim to get it exact). how random??? anyway here's the link for the 35mm(its cheap enough to just get it for the adapter) cgi.ebay.com/35mm-f-1-7-CCTV-Lens-C-Mount-Mirco-Ring-EP1-... ages ago (permalink)

I don't think I'm going to go through with the CF12.5A modification. I've disassembled, reassembled, but I can't bring myself to grind it. As maxnk expressed, I rather like the minor vignetting it provides (comparable to many 25mm cine c-mount coverage in 4:3 format)... and the modification will likely result in more chromatic abberation, corner softness all for 'fuller' sensor coverage. The vignetting is not so bad to begin. Eljustinoid, I love your photos in the 'one lens per post' thread in the 'alternative/legacy lens on m4/3' forum'. It's great to have you here as well. You're doing great work! ages ago (permalink)

Gas lasers consist of a gas filled tube placed in the laser cavity as shown in Figure 7.  A voltage (the external pump source) is applied to the tube to excite the atoms in the gas to a population inversion.  The light emitted from this type of laser is normally continuous wave (CW). One should note that if Brewster angle windows are attached to the gas discharge tube, some laser radiation may be reflected out the side of the laser cavity. Large gas lasers known as gas dynamic lasers use a combustion chamber and supersonic nozzle for population inversion.

I found one for £9.99 on eBay several months ago. I don't know how many of us are really looking for them, considering they need machining and other modifications. The other I purchased from eBay seller 'Calkovskycamerasandlensesco' for $99. The £9.99 one is in better shape. The one Calkovsky sold me has 'schneideritis', I tried to trade it for another and he told me he sold out. He's all 'praise Jesus' but he failed to mention the schneideritis (which DOES cause lower contrast, despite what Calkovsky, Schneider or any other so-called 'experts' may claim). I've been following zcream's attempts, and I don't think he'll have much joy beyond the Fujinon CF12.5A, unless he happens to find a Weinberger 8mm which is rare as rocking horse turds. ages ago (permalink)

Properties of laser

This range-gated, two-dimensional imaging camera system operates in the eye-safe Short Wave Infrared (SWIR) band and supports mounted and dismounted operations.

A laser generates a beam of very intense light.  The major difference between laser light and light generated by white light sources (such as a light bulb) is that laser light is monochromatic, directional and coherent.  Monochromatic means that all of the light produced by the laser is of a single wavelength.  White light is a combination of all visible wavelengths (400 - 700 nm).  Directional means that the beam of light has very low divergence.  Light from a conventional sources, such as a light bulb diverges, spreading in all directions, as illustrated in Figure 2.  The intensity may be large at the source, but it decreases rapidly as an observer moves away from the source.

With Multi-View Grow, you can browse several sites on single screen.

The laser output may be steady, as in continuous wave (CW) lasers, or pulsed.  A Q-switch in the optical path is a method of providing laser pulses of an extremely short time duration.  The Q-switch may use a rotating prism, a pockels cell or a shutter device to create the pulse.  Q-switched lasers may produce a high-peak-power laser pulse of a few nanoseconds duration.

Yep, that's the one... love the 'racing clouds' photo, maxnk. ages ago (permalink)

10 uses of laser

Here's the manual focus/manual iris C-mount Computar 12.5/1.3: cgi.ebay.de/COMPUTAR-TV-Lens-1-1-3-12-5mm-man-iris-2-3-Zo.... Nice price. I purchased a couple from this seller just the other day. ages ago (permalink)

This site uses cookies to improve your experience and to help show content that is more relevant to your interests. By using this site, you agree to the use of cookies by Flickr and our partners as described in our cookie policy

LASER full form

The primary wavelengths for lasers used at Princeton University include the ultraviolet, visible and infrared regions of the spectrum.  Ultraviolet radiation for lasers consists of wavelengths between 180 and 400 nanometers (nm).  The visible region consists of radiation with wavelengths between 400 and 700 nm. This is the portion we call visible light.  The infrared region of the spectrum consists of radiation with wavelengths between 700 nm and 1 mm.

Free electron lasers such as in Figure 8 have the ability to generate wavelengths from the microwave to the X-ray region. They operate by having an electron beam in an optical cavity pass through a wiggler magnetic field. The change in direction exerted by the magnetic field on the electrons causes them to emit photons.

A continuous wave laser has a steady power output, measured in watts (W).  For pulsed lasers, the output generally refers to energy, rather than power.  The radiant energy is a function of time and is measured in joules (J).  Two terms are often used to when measuring or calculating exposure to laser radiation.  Radiant Exposure is the radiant energy divided by the area of the surface the beam strikes.  It is expressed in J/cm2.  Irradiance is the radiant power striking a surface divided by the area of the surface over which the radiant power is distributed.  It is expressed in W/cm2.  For repetitively pulsed lasers, the pulse repetition factor (prf) and pulse width are important in evaluating biological effects.

Well here's a 13mm, and example photos. It vignettes a lot. Canon. Originally posted ages ago. (permalink) eljustinoid edited this topic ages ago.

The lasing material can be a solid, liquid, gas or semiconductor, and can emit light in all directions.  The pump source is typically electricity from a power supply, lamp or flashtube, but may also be another laser.  It is very common in Princeton University laboratories to use one laser to pump another.

Figure 5 illustrates the basic components of the laser including the lasing material, pump source or excitation medium, optical cavity and output coupler.

Coherent means that the waves of light are in phase with each other.  A light bulb produces many wavelengths, making it incoherent.

For some impressions made with the Fujinon 12.5mm f/1.4 click there: btw: I got mine for 20€ at a second-hand dealer.. ages ago (permalink)

I like the little Computar 12.5/1.3. After removing the stop screw, it reaches infinity and is quite nice. I just tried it with a Nikon x.68 wide angle converter. That increases the angle a little bit but after cropping out the picture to remove vignetting, the effect is minimal. BTW, I tried the same with a Cine Nikkor 10/1.6, similar results and very heavy vignetting. The Canon shown above is nice for its handling IMHO. I also have a Cosmicar TV 12.5/1.4 but I think that one is the weakest reg. IQ. I would love to see a comparison between the Computar and the Fujinon. Other than that, I think the quest continues... Stefan ages ago (permalink)

by S Singh · 1999 · Cited by 45 — A diffraction grating affects the propagation of a wave so that the energy is diffracted into various discrete directions of different orders. A grating ...

Uses of laser in Physics

@ ktf_design : Cool ! Did you cropped the pictures or they're full frame? ages ago (permalink)

The color or wavelength of light being emitted depends on the type of lasing material being used.  For example, if a Neodymium:Yttrium Aluminum Garnet (Nd:YAG) crystal is used as the lasing material, light with a wavelength of 1064 nm will be emitted.  Table 1 illustrates various types of material currently used for lasing and the wavelengths that are emitted by that type of laser.  Note that certain materials and gases are capable of emitting more than one wavelength. The wavelength of the light emitted in this case is dependent on the optical configuration of the laser.

Dye lasers employ an active material in a liquid suspension.  The dye cell contains the lasing medium.   These lasers are popular because they may be tuned to several wavelengths by changing the chemical composition of the dye.  Many of the commonly used dyes or liquid suspensions are toxic.

The Ultra Broadband Dielectric Mirrors are designed for use in applications where high-reflection over a wide range of wavelength is required.

The excitation medium is used to excite the lasing material, causing it to emit light.  The optical cavity contains mirrors at each end that reflect this light and cause it to bounce between the mirrors.  As a result, the energy from the excitation medium is amplified in the form of light.  Some of the light passes through the output coupler, usually a semi-transparent mirror at one end of the cavity.  The resulting beam is then ready to use for any of hundreds of applications.

Thank you all. Maxnk, those are informative. I have tried my 0.25x, opteka fisheye on a nikon f-mount 50mm. I will post the results later but i am not thrilled. if I find one for ~20 euros, I would get the fujinon. ages ago (permalink)

cgi.ebay.com/3-COMPUTAR-APC-TV-LENSES-12-5MM-1-1-3-plus-8... Is this the computar lens? Originally posted ages ago. (permalink) ulugeyik edited this topic ages ago.

Hi! Lenses of 12mm were compared in my blog. blogs.yahoo.co.jp/ktf_turbo/21864857.html ages ago (permalink)

The meaning of VIEW CAMERA is a camera having a rising, tilting, and swinging front, a removable lens board, a long bellows, a focusing cloth, ...

Objectives are designed to image specimens either with air or a medium of higher refractive index between the front lens and the specimen. The field of view is ...

I think, it was kind of luck to find one of these Fujinon lenses for this price. Thanks for the comments on my pictures! ages ago (permalink)