Double Lens Green
Coated or non-coated camera filters?
I just bought a new dslr (Pentax K-X) with 2 lenses. I would like to protect the lens and purchase a couple of filters (the lenses have different diameters). After doing some basic research I found that most people use UV or Skylight filters that double as lens protectors. Most of my pictures are indoors, so I probably will go for the UV filters.
Should I get the regular non-coated filters even though there is a risk of getting lens flare and ghosting?
Or should I shell out the extra bucks to get a multi-coated filter to minimize the risk of lens flare and ghosting?
The 2 lenses I have are coated (I can see a green glare when held up to the light).
I am currently looking at Hoya. B+W is much too expensive. I have read numerous negative reviews about flimsy construction and lousy material about Tiffen.
You should definitely use coated filters for the same reason your lens is multi-coated. Not only do coated filters minimize flare and ghosting when shooting toward bright lights (even if the lights are not within the image area), they result in better contrast in images shot in any light. Coated filters can also reduce the potential for reflections of the sensor to be reflected back through the lens and show up in photos shot at small apertures in environments where there is a lot of stray light getting into the lens from all angles, such as snowy scenes, water and beach scenes with high uniform brightness. For the same reasons, I recommend that people always use the lens hood - it protects the lens from physical abuse as well as keeping stray light out of the lens.
I use Hoya filters and recommend them.
 |
 |
170mW Green Purple Double Lens Laser show system Stage DJ Light DMX512 DISCO Bar |  |
 |
US $119.99 | 16d 5h 26m |
 |
160mW Purple(blue voilet) & Green Double lens Laser Light beam show System DJ | |
|
US $189.00 | 11d 23h 36m |
 |
160mW Double lens green and blue violet DJ laser light | |
|
US $215.00 | 27d 20h 36m |
 |
Disco Double Tunnel 150mW Red Green 2 Lens / Fach Laser Light Projector DMX512 | |
|
US $209.80 | 16d 8h 10m |
 |
Double Lens Blue Violet&green 160mw DJ club laser light | |
|
US $218.00 | 16d 4h 58m |
 |
50mW 2 lens Double Green Laser Light Stage DJ DISCO party KTV | |
|
US $89.99 | 10d 19h 32m |
 |
FREE SHIPPING 170mW Green Purple Double Lens GP Laser Stage DJ Light DISCO SHINP | |
|
US $199.99 | 8d 4m |
 |
250mW 4 Lens Double Red + Green DMX DMX512 Laser Lighting For DJ Party Bar KTV | |
|
US $199.00 | 5d 20h 9m |
 |
250mW Red Green Double Lens Laser. Plug N PLay. DJ | |
|
US $134.95 | 25d 19h 53m |
 |
270mW Red Green Double Lens Laser. Plug N PLay. DJ | |
|
US $190.00 | 14d 19h 36m |
 |
4 Lens 250mW Double Red + Green DMX512 Laser Lighting For DJ Party Bar KTV DMX | |
|
US $197.00 | 9d 19h 51m |
 |
Double Lens 2 lens Green 50mW Beam Show Laser Light DJ Party Lighting Fast ship | |
|
US $148.88 | 6d 22h 30m |
| Powered by phpBay Pro |
|
No items matching your keywords were found.
| Account limit of 2098 requests per hour exceeded. |
4 LENS, DOUBLE RED/GREEN 210mW LASER DISCO LIGHT
Underwater vision
Fish
The crystalline lenses of fishes' eyes are extremely convex, almost spherical, and their refractive indices are the highest of all the animals. These properties enable proper focusing of the light rays and in turn proper image formation on the retina.
Masks and Goggles
Views through a flat mask, above and below water
By wearing a flat diving mask, humans can see clearly under water. The scuba mask's flat window separates one's eyes from the surrounding water by a layer of air. Light rays entering from water into the flat parallel window change their direction minimally within the window material itself. But when these rays exit the window into the air space between the flat window and the eye, the refraction is quite noticeable. The view paths refract (bend) in a manner similar to viewing fish kept in an aquarium. Linear polarizing filters decrease visibility underwater by limiting ambient light and dimming artificial light sources.
While wearing a flat scuba mask or goggles, objects underwater will appear 33% bigger (34% bigger in salt water) and 25% closer than they actually are. Also pincushion distortion and lateral chromatic aberration are noticeable. Double-dome masks restore natural sized underwater vision and field of view, with certain limitations.
Color vision
Water is responsible for the attenuation of light due to absorption. In other words, as we go deeper on a dive, more color is absorbed by the water. Color vision is also affected by turbidity of the water as well as particulate matter.
The best colors to use for visibility in water was shown by Luria et al. and quoted from Adolfson and Berghage below:
A. For murky, turbid water of low visibility (rivers, harbors, etc.)
1. With natural illumination:
a. Fluorescent yellow, orange, and red.
b. Regular yellow, orange, and white.
2. With incandescent illumination:
a. Fluorescent and regular yellow, orange, red and white.
3. With a mercury light source:
a. Fluorescent yellow-green and yellow-orange.
b. Regular yellow and white.
B. For moderately turbid water (sounds, bays, coastal water).
1. With natural illumination or incandescent light source:
a. Any fluorescent in the yellows, oranges, and reds.
b. Regular yellow, orange, and white.
2. With a mercury light source:
a. Fluorescent yellow-green and yellow-orange.
b. Regular yellow and white.
C. For clear water (southern water, deep water off shore, etc.).
1. With any type of illumination fluorescent paints are superior.
a. With long viewing distances, fluorescent green and yellow-green.
b. With short viewing distances, fluorescent orange is excellent.
2. With natural illumination:
a. Fluorescent paints.
b. Regular yellow, orange, and white.
3. With incandescent light source:
a. Fluorescent paints.
b. Regular yellow, orange, and white.
4. With a mercury light source:
a. Fluorescent paints.
b. Regular yellow, white.
The most difficult colors at the limits of visibility with a water background are dark colors such as gray or black.
Trivia
Lists of miscellaneous information should be avoided. Please relocate any relevant information into appropriate sections or articles. (January 2008)
A very short-sighted person (eyesight abnormality resulting from the eye's faulty refractive index due to which the distant objects appear blurred) can see more or less normally under water.
The Moken people of South-East Asia are able to focus underwater to pick up tiny shellfish and other food items . Gisln et al. have compared Moken and European children and found that the visual acuity of the Moken was twice that of their European counterparts. This ability appears to be due to training rather than evolution or genetics.
See also
Snell's law
References
^ a b c d e f g Adolfson J and Berhage, T (1974). Perception and Performance Under Water. John Wiley & Sons. ISBN 0471009008.
^ a b c Luria SM, Kinney JA (March 1970). "Underwater vision". Science (journal) 167 (924): 145461. PMID 5415277. http://www.sciencemag.org/cgi/pmidlookup?view=long&pmid=5415277. Retrieved 2008-07-06.
^ Weltman G, Christianson RA, Egstrom GH (October 1965). "Visual fields of the scuba diver". Hum Factors 7 (5): 42330. PMID 5882204.
^ Luria SM, Kinney JA (December 1974). "Linear polarizing filters and underwater vision". Undersea Biomed Res 1 (4): 3718. PMID 4469103. http://archive.rubicon-foundation.org/2668. Retrieved 2008-07-06.
^ Gisln A, Dacke M, Krger RH, Abrahamsson M, Nilsson DE, Warrant EJ (May 2003). "Superior underwater vision in a human population of sea gypsies". Curr. Biol. 13 (10): 8336. doi:10.1016/S0960-9822(03)00290-2. PMID 12747831. http://linkinghub.elsevier.com/retrieve/pii/S0960982203002902. Retrieved 2008-07-06.
^ Gisln A, Warrant EJ, Dacke M, Krger RH (October 2006). "Visual training improves underwater vision in children". Vision Res. 46 (20): 344350. doi:10.1016/j.visres.2006.05.004. PMID 16806388. http://linkinghub.elsevier.com/retrieve/pii/S0042-6989(06)00236-7. Retrieved 2008-07-06.
Please help improve this article by adding reliable references. Unsourced material may be challenged and removed. (January 2008)
Further reading
Chou, B; Legerton, JA; Schwiegerling, J. "Improving Underwater Vision: Contact lenses and other options can help patients safely maximize their vision underwater.". Contact Lens Spectrum (June 2007). http://www.clspectrum.com/article.aspx?article=100720. Retrieved 2009-06-27.
Categories: Vision | Underwater divingHidden categories: Articles with trivia sections from January 2008 | All articles with trivia sections | Articles needing additional references from January 2008 | All articles needing additional references
About the Author
I am a professional editor from
China Manufacturers
, and my work is to promote a free online trade platform.
http://www.cheaponsale.com/ contain a great deal of information about
square glass candle
,
hand carved candles
welcome to visit!
