snubbr.com

What is a stop?
I see alot of people talking about this camera being one stop better than that camera. What is meant by a stop?..

Comments (9)

Crwdz7 wrote:.

I see alot of people talking about this camera being one stop betterthan that camera. What is meant by a stop?.

You wont be able to learn what a stop is if you dont learn about what exposure is..

This tutorial is quite good because it doesnt assume that you know anything about photography..http://daystarvisions.com/Docs/Tuts/Meter/pg1.html..

Comment #1

See chart middle of page http://en.wikipedia.org/wiki/ApertureTelecorder (Dave)FZee30+RD-S+OlyTC1.7XDee50+Nikon 35mm F2.0D-AF+Nikkor18-70DX+Tam70-300L+BIGMA 50-500 EX HSMMy Image Galleries.

Http://www.nikonians-images.com/...hp?cat=500&ppuser=121399&password=.

Http://Telecorder.smugmug.com/.

Image control:Zoom outZoom 100%Zoom inExpand AllOpen in new window..

Comment #2

Crwdz7 wrote:.

I see alot of people talking about this camera being one stop betterthan that camera. What is meant by a stop?.

Ziggy25 is right - learn about exposure! But the answer to the question is this....

The amount of light that a lens can gather depends on the size of the lens opening (the 'aperture') and also on the field of view. If the aperture is smaller, obviously it collects less light. It's probably a little less obvious, but if the field of view is smaller less light is collected too..

Skipping a lot of the explanation, the result of this is that you can obtain a very useful measure of the light-collecting power by dividing the focal length by the diameter of the aperture, and the result is called the f-number. All lenses at f/4, for example, have an aperture which is 1/4 of the focal length, and all produce the same brightness of image on the film/sensor..

Traditionally, on fully manual cameras, there was a lever which adjusted the aperture. It was fitted with notches which conveniently located it at successive steps, the increment between them being the right amount to give double the aperture area and therefore double the brightness between notches. This ties in nicely with shutter speeds, which also halve/double. The notched positions were called 'f-stops'..

Nowadays we use the term 'stop' in the broader sense of any setting which doubles/halves the exposure, so the difference between shutter speeds can be stated in stops, as can ISO speed, and also the strength of neutral density filters..

Just one thing left to explain. Half the brightness requires half the *area* of lens opening, but the f-number is proportional to the inverse of the *diameter*. So instead of f-numbers doubling between stops, they go up by the square root of 2, which is approximately 1.4..

1 - 1.4 - 2 - 2.8 - 4 - 5.6 - 8 - and so forth...

Comment #3

1 stop equals:.

Double or halve shutter speed (1/100>1/200, or 1/100>1/50).

A change in f-stop values of: f/1>f/1.4>f/2>f/2.8>f/4f/5.6>f/8>f/11>f/16>f/22 etc.Tim'Be the change you wish to see in the world.' -Mahatma Gandhihttp://www.flickr.com/photos/timskis6/..

Comment #4

Telecorder wrote:.

See chart middle of page http://en.wikipedia.org/wiki/Aperture.

It must be a slow morning and I haven't had my second cup of ambition because I really like this type of discussion. I was cruising through the wikipedia article and came across a reference to T factor, for Transmission, that the movie industry uses. They calibrate their system for how much light is transmitted through the lens with the same physical F Stop. I've noticed this with my lens. Another slow day I was doing a lens test and found with the same scene and each lens set at the same aperture I would get a slightly different shutter speed. I can only think that one lens has better glass, attenuating the light less, allowing a higher shutter speed..

Well like I said it's a slow morning and looks like it may rain in central Florida and I found this more interesting then cleaning house. Back to the coffee pot..

Doug.

Http://douginoviedo.smugmug.com/..

Comment #5

Doug Gabler wrote:.

Telecorder wrote:.

See chart middle of page http://en.wikipedia.org/wiki/Aperture.

It must be a slow morning and I haven't had my second cup of ambitionbecause I really like this type of discussion. I was cruisingthrough the wikipedia article and came across a reference to Tfactor, for Transmission, that the movie industry uses. Theycalibrate their system for how much light is transmitted through thelens with the same physical F Stop. I've noticed this with my lens.Another slow day I was doing a lens test and found with the samescene and each lens set at the same aperture I would get a slightlydifferent shutter speed. I can only think that one lens has betterglass, attenuating the light less, allowing a higher shutter speed..

Well like I said it's a slow morning and looks like it may rain incentral Florida and I found this more interesting then cleaninghouse. Back to the coffee pot..

Doug.

And, by extension, why 'good glass' is more expensive and gives better IQ... LOL.

Telecorder (Dave)FZee30+RD-S+OlyTC1.7XDee50+Nikon 35mm F2.0D-AF+Nikkor18-70DX+Tam70-300L+BIGMA 50-500 EX HSMMy Image Galleries.

Http://www.nikonians-images.com/...hp?cat=500&ppuser=121399&password=.

Http://Telecorder.smugmug.com/.

Image control:Zoom outZoom 100%Zoom inExpand AllOpen in new window..

Comment #6

Metering a few inches apart in a given scene can give exposure readings a few stops apart. This will significantly change the shutter speed. Even small metering differences on the same subject can give slightly different exposure readings..

It is more likely that you metered on a different part of the scene, even it if was only an inch apart..

A difference in glass would have to be very significant to affect exposure by even 1/3 stop..

Tim'Be the change you wish to see in the world.' -Mahatma Gandhihttp://www.flickr.com/photos/timskis6/..

Comment #7

But the motion picture industry apparently thinks it is important. But then again it's the motion picture industry, the people that brought us Dumb and Dumber, LOL..

Timskis6 wrote:.

Metering a few inches apart in a given scene can give exposurereadings a few stops apart. This will significantly change theshutter speed. Even small metering differences on the same subjectcan give slightly different exposure readings..

It is more likely that you metered on a different part of the scene,even it if was only an inch apart..

A difference in glass would have to be very significant to affectexposure by even 1/3 stop..

Tim'Be the change you wish to see in the world.' -Mahatma Gandhihttp://www.flickr.com/photos/timskis6/.

Doug.

Http://douginoviedo.smugmug.com/..

Comment #8

I am a complete newbie and I read the daystar tutorials and they are very helpful!.

Although I understood the basic concept behind aperture and shutter speed it seemed like so many variables at once that I could find no fixed point from which to depart. so this is a great helpthanks S t..

Comment #9

Click Here to View All...

Sponsored Amazon Deals:

1. Get big savings on Amazon warehouse deals.
2. Save up to 70% on Amazon Products.


This question was taken from a support group/message board and re-posted here so others can learn from it.

 

Categories: Home | Diet & Weight Management | Vitamins & Supplements | Herbs & Cleansing |

Sexual Health | Medifast Support | Nutrisystem Support | Medifast Questions |

Web Hosting | Web Hosts | Website Hosting | Hosting |

Web Hosting | GoDaddy | Digital Cameras | Best WebHosts |

Web Hosting FAQ | Web Hosts FAQ | Hosting FAQ | Hosting Group |

Hosting Questions | Camera Tips | Best Cameras To Buy | Best Cameras This Year |

Camera Q-A | Digital Cameras Q-A | Camera Forum | Nov 2010 - Cameras |

Oct 2010 - Cameras | Oct 2010 - DSLRs | Oct 2010 - Camera Tips | Sep 2010 - Cameras |

Sep 2010 - DSLRS | Sep 2010 - Camera Tips | Aug 2010 - Cameras | Aug 2010 - DSLR Tips |

Aug 2010 - Camera Tips | July 2010 - Cameras | July 2010 - Nikon Cameras | July 2010 - Canon Cameras |

July 2010 - Pentax Cameras | Medifast Recipes | Medifast Recipes Tips | Medifast Recipes Strategies |

Medifast Recipes Experiences | Medifast Recipes Group | Medifast Recipes Forum | Medifast Support Strategies |

Medifast Support Experiences |

 

(C) Copyright 2010 All rights reserved.