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Topic: Dioptre


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Jan

  
  Taking Macros with Close-up lens
The fl one is 5 dioptres and the clear one is 10 dioptres.
A one dioptre has a focal length of 1000mm and a quarter dioptre, as you might find in a pair of glasses, has a focal length of 4 metres.
Below is a grub using a 2 dioptre on the 5700 with full zoom from a distance of about 9 inches.
www.geocities.com /nikon5700itee/dioptres.html   (998 words)

  
 Acute near sightedness – Acute myopia - More relevant information about Acute near sightedness – Acute myopia
The reasons for acute close sightedness are interruptions in the eye function which places the eye too far away from the cornea and the lenses light protection capacity.
If close sightedness is stronger than a factor of minus 6 or minus 7 dioptre then Acute-myopia is indeed a problem.
It can be reconfigured with spectacles and contact lenses albeit with some complications.
www.lensshopper.com /eye-disorders/acute-nearsightedness.asp   (260 words)

  
  Using Nikon Binoculars
Looking through binoculars without dioptre adjustment will not yield a sharp, crisp image because one eye sees things in focus while the other doesn' t.
When the dioptre is adjusted, turn the central focusing ring to focus on the object.
Focusing and dioptre adjustments are performed simultaneously, but a change of object requires both ring.
nikon.topica.ne.jp /bi_e/encyclo/using.htm   (336 words)

  
 Dioptre
A dioptre, or diopter, is a unit of measurement of the optical power of a lens or curved mirror, which is equal to the reciprocal of the focal length measured in metres (that is, 1/metres).
For example, a 3 dioptre lens brings parallel rays of light to focus at 1/3 metre.
The dioptre can also be used as a measurement of curvature equal to the reciprocal of the radius measured in metres.
www.photonicsknowledge.com /optics/Dioptre   (676 words)

  
 Reading Glasses and Sunglasses   (Site not responding. Last check: 2007-10-21)
If you've used a magnifying glass the focal length is the distance from the lens where the smallest point of light is produced (focal point).
To find the Dioptre of a lens follow these steps - (a) With the eyes 10" from the lens, move the object being viewed as far away from the lens where it's still in sharp focus.
For example, if the object maximum sharp focus distance from the lens is 50 centimetres the Dioptre is 2.
www.specky4eyes.co.uk /measuring_dioptre.asp   (122 words)

  
  Spartanburg SC | GoUpstate.com | Spartanburg Herald-Journal   (Site not responding. Last check: 2007-10-21)
A dioptre, or diopter, is a non-SI unit of measurement of the optical power of a lens or curved mirror, which is equal to the reciprocal of the focal length measured in metres (that is, 1/metres).
As humans age, the amplitude of accommodation reduces from approximately 15 to 20 dioptres in the very young, to about 10 dioptres at age 25, to around 1 dioptre at 50 and over.
The dioptre can also be used as a measurement of curvature equal to the reciprocal of the radius measured in metres.
www.goupstate.com /apps/pbcs.dll/section?category=NEWS&template=wiki&text=Dioptre   (610 words)

  
  Dioptre   (Site not responding. Last check: 2007-10-21)
A dioptre (also diopter) is a unit of curvature equal to one per metre.
A circle with radius 1/2 metre has a curvature of 2 dioptres.
It is also used to measure focus ing power of lenses and (curved) mirror s; in this case, the power is the inverse of the focal length.
www.serebella.com /encyclopedia/article-Dioptre.html   (154 words)

  
 Macro photography by Mohammed Belarbi
The dioptre measurement is the reciprocal of the focal length of the lens measured in metres.
Therefore a +1 dioptre lens is 1 metre focal length, a +2 is 500mm and a +4 is 250mm.
A lens of higher dioptre rating is required to achieve a magnification large enough to capture the fine details.
www.belarbi.net /Macro.htm   (2913 words)

  
 [No title]
We have two daughters aged 15 and 11 both of whom have eyes that are almost perfect as far as spherical corrections are concerned they are both at 0 dioptre +/-.25.
My reasoning was that since my eyes had stabilized at about -1.00 to -1.25 dioptre that reading glasses of +1.25 dioptre would probably be about the right level for them.
A l said that both of the girls had very little reserve in their eyes and would both be myopic by the time they were 15.
www.i-see.org /archive/alarie   (3446 words)

  
 Definition of Dioptre
A dioptre (also diopter) is a unit of curvature equal to one per metre; that is, inverse metres, or 1/(metres).
A circle with radius 1/2 metre has a curvature of 2 dioptres.
The dioptre is not an SI unit, and is typically used to measure focusing power of lenses and (curved) mirrors; in this case, the power is the inverse of the focal length.
www.wordiq.com /definition/Dioptre   (196 words)

  
 Dan's Data letters #155
The usual reason why directors use split dioptre is that it lets you use a lens with a large aperture - to let in lots of light - and still manage something resembling good depth of field.
Split dioptre lenses are also used in still photography; they can be had as screw-on filters for various still and motion picture camera lenses, as well as whole separate lenses.
One big split dioptre market - which is to say, it's big by the standards of strange-niche-lens sales - is for underwater photography, when someone wants to take one of those tricky half-underwater shots with the waterline through the middle of the frame, without cheating and just assembling the shot in Photoshop.
www.dansdata.com /danletters155.htm   (1908 words)

  
 Buy the patent: Far or myopia treatment device (no surgical or laser needed) (Patent for sale)
This kind of visual disturbances (or sight defect) are repaired by an operation, a dioptre suitable eyeglasses or contact lenses.
The speed, with which the changes of dioptre arise, can be programmed before also according to desire of the patient.
Also the eye is also pulled in by this dioptre oscillation of the equipment into the process.
www.freepatentauction.com /patent.php?nb=1470   (6900 words)

  
 FINEcut - the use of Macro and Close-up Lens   (Site not responding. Last check: 2007-10-21)
However, when using a supplementary close-up lens, the camcorder is placed at a distance dictated by the dioptre rating, about nine and threequarter inches with a four dioptre.
The required focal distance between the subject and the close-up lens is determined by dividing the dioptre figure into one metre.
Thus a two dioptre lens must be positioned 500mm (approximately 19.5 inches) from the subject matter whilst a four diopter would be 250mm.
www.bonus.com /contour/eye_works/http@@/www.terrymen.demon.co.uk/don_cu.htm   (1232 words)

  
 Optics Main Page
Scope lenses are sometimes shown as having a power in dioptres (eg +0.75 or just 0.75), and sometimes as magnification (eg 6x), but the magnification number is almost meaningless.
The simple fact is that you cannot convert dioptres to magnification without knowing the eye-to-lens distance, and this varies greatly not only between archers, but between set-ups.
Many archery manufacturers appear to use the rule of thumb that magnification = dioptres x 8, but this wildly misleading and only the dioptre value itself is reliable as it doesn't change however the lens is used.
www.alansarchery.pwp.blueyonder.co.uk /Equipment/Optics/optics01.htm   (1942 words)

  
 Dioptre   (Site not responding. Last check: 2007-10-21)
A dioptre, or diopter, is a non-SI unit of measurement of the optical power of a lens or curved mirror, which is equal to the reciprocal of the focal length measured in metres (i.e.
The power of the eye's lens and cornea together is very high, about 40 dioptres, and the normal accommodation range of a young person is a further 15 to 20 dioptres.
The dioptre can also be used as a measurement of curvature equal to the reciprocal of the radius measured in metres.
www.omniknow.com /common/wiki.php?in=en&term=Diopter   (1913 words)

  
 Contact Lens Shop your onestop online disposable soft or toric contact lenses shop australia gold coast and new zealand
This figure represents the power in Dioptres of the spherical lens required to correct your sight.
Hypermetropic people generally have more difficulty seeing close work clearly however depending on the degree of Hypermetropia and age of the person the prescription may be required for distance viewing as well.
This type of lens is used to correct double vision, either intermittent or constant (which is called a Tropia), or a tendency of the eyes to not work perfectly together, and one eye wanting to drift slightly, (this is called a Phoria).
www.contactlensshop.com.au /prescriptions.html   (2993 words)

  
 [No title]
Although not yet generally accepted, the addition of diagnostic refraction takes little time, while enabling the general practitioner to determine whether the visual complaints are caused by myopia or hyperopia, or the wearing of incorrect glasses or contact lenses, or that they are not due to a refractive disorder.
For 2 dioptres the focal distance is ½ metre in front of or behind the lens, and for x dioptres it is 1/x metres.
The total refractive power of these media in the unaccommodated eye is about 58 dioptres; the contribution of the cornea to this is about 43 dioptres and that of the lens is about 15 dioptres.
nhg.artsennet.nl /upload/104/guidelines2/E12.htm   (5571 words)

  
 What is a close-up filter?
Though you often see a close-up lens referred to as a "dioptre" - usage akin to calling an electric heater a "watt" - a dioptre is actually a unit for measuring the converging power of a lens.
I grew up with "dioptre", but this is one of these cases where the division between British and American spelling isn't clear cut.
If you use units other than millimetres for the focal lengths, the dioptre values will be wrong, but the combination focal length correct, as long as the units are the same.
www.imaginatorium.org /stuff/cufilter.htm   (1590 words)

  
 10x50 Orion Vista vs Carton Adlerblick - Review
Although the dioptre  adjustment is stiffer in the Orions I prefer it slightly, as it tends to drift less.
On the Cartons, however, the dioptre markings are moulded into the rubber surround of the EP, making them difficult to see at night.
It you are sharing the binoculars with someone who sets the dioptre differently than you, this can be annoying under dark skies.
www.cloudynights.com /item.php?item_id=1434   (1226 words)

  
 What is a close-up filter?
Though you often see a close-up lens referred to as a "dioptre" - usage akin to calling an electric heater a "watt" - a dioptre is actually a unit for measuring the converging power of a lens.
I grew up with "dioptre", but this is one of these cases where the division between British and American spelling isn't clear cut.
If you use units other than millimetres for the focal lengths, the dioptre values will be wrong, but the combination focal length correct, as long as the units are the same.
imaginatorium.org /stuff/cufilter.htm   (1590 words)

  
 Visual Perception - Distinct human eye
The range of distances animals can focus on is measured in dioptre.
A child's sight is about fourteen dioptres, and an old person's is about one dioptre.
However, diving birds have 50 dioptres -- the greatest of all animals.
www.artinarch.com /vp05.html   (671 words)

  
 British Garden Birds - Binoculars
Binoculars should have an individual eye (or dioptre) adjustment, often on one of the eyepieces, but sometimes part of the main central focussing mechanism.
The right eyepiece incorporates the dioptre ring for individual eye adjustment, this tends to move unintentionally but a rubber band wrapped around it stops this from happening.
My mother has a much better pair of binoculars, a pair of 8x32 RSPB FG.PC, though not strictly compact they are small enough to put in a large coat pocket or day sack.
www.garden-birds.co.uk /information/binoculars.htm   (1056 words)

  
 ePHOTOzine.com - Forums - Diopter Lenses - Are these any good.
Just avoid 'stacking' dioptres, that set will give you a 7 dioptre effect but with considerable loss of quality.
I normally use a 2 dioptre as a compromise between closeness and results, otherwise with a DSLR there is the extension tube or bellows.
The most 'interesting' CU lens I have is a 7 dioptre, being a 145mm multi element lens which originally was used on a large format camera for copying purposes.
www.ephotozine.com /forum/viewanswers.cfm?qid=42307   (841 words)

  
 Lens with surface correction - Patent 6364481
An optical lens element according to claim 6, wherein the reduction in base-nasal prism is in the range of 0.75 to 2.0 prism dioptre.
An optical tens element according to claim 1, wherein the lens element further includes a secondary prismatic correction in the optical zone to assist in ensuring that the primary line of sight is undisturbed, with the lens element in the as-worn position.
5, a 3 prism dioptre prismatic deviation, corresponding to a field loss of 2.3.degree., is characteristic of existing piano lenses at 115.degree.
www.freepatentsonline.com /6364481.html   (5687 words)

  
 Ball Anemone
This has a +4 dioptre on the bottom half and a 2 f stop ND filter on the top.
I intended to use the camera with a Nikon 20mm lens to take shots of seals on the rocks from the water (which I never did succeed in doing as the water was too choppy).
Using the 16mm fisheye gets you around a lot of difficulties (you don't need the split dioptre so autofocus and metering work and you're not constrained to a single camera orientation) and this would now be my choice.
users.bigpond.net.au /abowie/OUfiles.htm   (398 words)

  
 Snorkel-Mart : How to Choose a Prescription Lens
Our Negative Step Dioptre lenses are available from -1.0 to -10.0 in increments of -0.5, while our Positive Step Dioptre lenses are available from +1.0 to +4.0 in increments of +0.5.
So in example #3 the best Step Dioptre lens for the right eye would be -4.5, and the best lens for the left eye would be -3.25.
As Step Dioptre lenses increase in increments of -0.5 it may not be possible to exactly match your requirements.
www.snorkel-mart.com /files/helpful_links/choose_prescription_lens.cfm   (780 words)

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