Fermat's theorem (stationary points): Difference between revisions

From formulasearchengine
Jump to navigation Jump to search
en>Tkuvho
en>MusikAnimal
m Reverted edits by 130.126.218.209 (talk) (HG)
 
Line 1: Line 1:
[[Image:B35 Zeiss Triotar40mm.jpg|thumb|The Carl Zeiss 40mm Triotar lens referred to in Jacobson's lens tutorial.<ref name=jlens/> The dots represent DOF limits for {{f/|8|link=yes}} and {{f/}}16; the dots indicate that the lens is focused at approximately the [[hyperfocal distance]] for {{f/}}16, about 13 feet. Jacobson's inferred [[circle of confusion]] diameter, using <math> c = f\,^2 / (N H)</math>, was about 0.025 mm.]]
free psychic reading ([http://www.zavodpm.ru/blogs/glennmusserrvji/14565-great-hobby-advice-assist-allow-you-get-going www.zavodpm.ru]) I would like to introduce myself to you, I am Andrew and my wife doesn't like it at all. For years he's been living in Mississippi and he doesn't plan on altering it. What me and my family members love is to climb but I'm considering on beginning psychic love readings ([http://black7.mireene.com/aqw/5741 mireene.com]) something new. Office supervising is exactly where her primary income comes from.<br><br>Check out my blog post :: [http://www.edmposts.com/build-a-beautiful-organic-garden-using-these-ideas/ online psychics]
 
In [[photography|photographic]] [[optics]], the '''Zeiss formula''' is a supposed formula for computing a [[circle of confusion]] (CoC) criterion for [[depth of field]] (DoF) calculations.  The formula is <math>c = d/1730</math>, where <math>d</math> is the diagonal measure of a camera format, film, sensor, or print, and <math>c</math> the maximum acceptable diameter of the circle of confusion.
 
The Zeiss formula is [[apocryphal]], in the sense that it has grown to be a well-known named concept by propagation through the internet, even though it has no official origin, little connection to [[Carl Zeiss AG|Carl Zeiss Company]], and no recognition or usage in the photographic industry outside the web community.
 
The number 1/1730 derives from a circle of confusion diameter of 0.025 mm on a full-frame 35 mm [[film format]], with diagonal size about 43.25 mm (43.25/0.025 is 1730).  The CoC size of 0.025 mm for this format appears in Jacobson's Photographic Lenses Tutorial,<ref name=jlens>
{{cite web
| title = Photographic Lenses Tutorial
| url =  http://www.faqs.org/faqs/rec-photo/lenses/tutorial/
| work = rec-photo
| author = David Jacobson
| accessdate =  2006
| date = 1996
| quote = Although there is no one diameter that marks the boundary between fuzzy and clear, .03 mm is generally used in 35mm work as the diameter of the acceptable circle of confusion. (I arrived at this by observing the depth of field scales or charts on/with a number of lenses from Nikon, Pentax, Sigma, and Zeiss. All but the Zeiss lens came out around .03mm. The Zeiss lens appeared to be based on .025 mm.)
}}</ref>
and the 1730 in his 1996 Photographic Lenses FAQ.<ref>
{{cite web
| title = Photographic Lenses FAQ
| url = http://www.faqs.org/faqs/rec-photo/lenses/faq/
| work = rec-photo
| author = David Jacobson
| accessdate =  2006
| date = 1997
| quote = There is no one circle 'small enough' for all circumstances, but rather it depends on how much the image will be enlarged, the quality of the rest of the system, and even the subject. Nevertheless, for 35mm work c=.03mm is generally agreed on as the diameter of the acceptable circle of confusion. Another rule of thumb is c=1/1730 of the diagonal of the frame, which comes to .025mm for 35mm film. (Zeiss and Sinar are known to be consistent with this rule.)
}}</ref>
Jacobson derived the 0.025 mm CoC number from analysis of the Zeiss [[Triotar]] lens DoF markings on the [[Rollei 25|Rollei B35]] (see photo).  The manual for the Rollei B35 also states 0.025 mm CoC for its tabulated DoF distances, though it also includes an example DoF reading that implies a larger CoC.<ref>
{{cite web
| title = Rollei B35 / C35
| url =  http://www.butkus.org/chinon/rollei/rollei_b35_c35/rollei_b35_c35.htm
| work = On-line camera manual library of Mike Butkus
  |  publisher = Rollei-Werke
| accessdate =  2006
}}</ref>
 
By 2001, the term "Zeiss formula" had appeared, in the manual for the on-line DoF calculator f/calc.<ref>
{{cite web
| title = Chapter 14. What Is the “Circle of Confusion”?
| url =  http://fcalc.net/manual/coc.html
| work = ƒ/Calc Manual
| author = Warren Young
|  publisher =
| accessdate =  2006
| quote = ƒ/Calc calculates the CoC using the Zeiss formula: d/1730, where d is the diagonal measure of the imaging area, in millimeters.
}}</ref>
 
On the other hand, Zeiss gives the values ''d''/1000 as the traditional standard and ''d''/1500 as the modern standard.<ref>
{{cite web
| title = Depth of Field – An Insider’s Look
| url =  http://www.zeiss.com/C12567A8003B8B6F/EmbedTitelIntern/CLN01e/$File/CLN1.pdf
| work = Camera Lens News #1
| date = 1997
| author =
|  publisher = Carl Zeiss AG
| accessdate =  2013
| quote = A certain amount of blur is supposed to be tolerable. According to international standards the degree of blur tolerable is defined as 1/1000 of the camera format diagonal, as the normally satisfactory value. With 35mm format and its 43 mm diagonal only 1/1500 is deemed tolerable, resulting in 43 mm/1500 ≈ 0.030 mm.
}}</ref>
 
==See also==
 
*[[Circle of confusion]]
*[[Depth of field]]
*[[Hyperfocal distance]]
 
==References==
 
{{reflist}}
 
[[Category:Science of photography]]

Latest revision as of 20:30, 15 December 2014

free psychic reading (www.zavodpm.ru) I would like to introduce myself to you, I am Andrew and my wife doesn't like it at all. For years he's been living in Mississippi and he doesn't plan on altering it. What me and my family members love is to climb but I'm considering on beginning psychic love readings (mireene.com) something new. Office supervising is exactly where her primary income comes from.

Check out my blog post :: online psychics