Pixalo Photography Community

Go Back   Pixalo Photography Community > Photography Forums > General photography questions and answers

General photography questions and answers: Discuss What does "Stops" mean in Photography ?...Been reading about histogram...The word "stops" keeps coming up how does this relate to shutter speed and aperture ? The ...
Welcome to the Pixalo Photography Community. As a Guest you are free to browse the site, but see what extras you get as a Member here.


Reply
 
LinkBack Thread Tools Display Modes
Old 21-09-2007, 10:50   #1 (permalink)
Quite Chatty
 
Join Date: Sep 2007
Location: Lordswood, Kent
Posts: 86
ise438 is on a distinguished roadise438 is on a distinguished road

Image editing O.K.
User's Gallery
Users Camera Equipment List
What does "Stops" mean in Photography ?

Been reading about histogram...The word "stops" keeps coming up how does this relate to shutter speed and aperture ?

The guy mentioned the following...



"The shot was about 8 stops. You therefore have to make some decisions on how to handle such a scene. To stuff 8 stops worth of dynamic range into a recorded image that can only handle 5 stops your choices are...."
use balanced fill flash on the foreground
use a graduated neutral density filter
take multiple exposures and merge them digitally
go home
He shot the two frames at about 3 1/2 stops apart and merged them digitally
ise438 is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote
Old 21-09-2007, 11:09   #2 (permalink)
Loves the place
 
silkstone's Avatar
 
Join Date: Jan 2005
Location: Silkstone Common, Yorkshire, UK
Posts: 5,719
silkstone is a glorious beacon of lightsilkstone is a glorious beacon of light
silkstone is a glorious beacon of lightsilkstone is a glorious beacon of lightsilkstone is a glorious beacon of lightsilkstone is a glorious beacon of lightsilkstone is a glorious beacon of lightsilkstone is a glorious beacon of lightsilkstone is a glorious beacon of lightsilkstone is a glorious beacon of lightsilkstone is a glorious beacon of lightsilkstone is a glorious beacon of lightsilkstone is a glorious beacon of light

Image editing O.K.
User's Gallery
Users Camera Equipment List
Re: What does "Stops" mean in Photography ?

A 'stop' is an increment of aperture or exposure. With aperture it goes....

f/1.4, f/1.8. f/2.8, f/4, f/5.6, f/8, f/11, f/16, f/22, etc.

f/1.4 is the largest aperture - f/22 is the smallest.

Each increment lets half as much light into the camera, so opening the aperture (which means reducing the f/number) by one stop has the same effect as halving the shutter speed.

It's probably more correct to talk in terms of 'Exposure Value' (EV) which has the same general meaning but can be applied to both shutter speed and aperture. i.e. 1EV means an increase or decrease of one stop (increment) of aperture, or doubling or halving the shutter speed.

In the case you mention, he means that the difference between the lightest and darkest parts of the image was 8EV (or 8 stops) - that's the 'dynamic range' of the scene. He says that the camera's sensor can only handle 5EV - any more than this and the shadows become black with no detail, or the highlights are 'blown' to white, again with no details.

The technique he is using to overcome this is called 'High Dynamic Range' (HDR) photography where you take several shots and different exposures and combine them by taking the shadow detail from one shot and the highlight detail from another - so you are compressing the dynamic range of the scene into something that can be reproduced as a photograph. There is software designed specifically to help you do this, such as Photomatix, but you can also do it on many image editors.

HTH!
silkstone is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote
Old 21-09-2007, 11:19   #3 (permalink)
Quite Chatty
 
Join Date: Sep 2007
Location: Lordswood, Kent
Posts: 86
ise438 is on a distinguished roadise438 is on a distinguished road

Image editing O.K.
User's Gallery
Users Camera Equipment List
Re: What does "Stops" mean in Photography ?

Excellent reply...thanks..

So how can you tell if a shot is going to have more the 5EV ?

If there a technique that can be used or if it just down to experience ?
ise438 is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote
Old 21-09-2007, 11:42   #4 (permalink)
Loves the place
 
silkstone's Avatar
 
Join Date: Jan 2005
Location: Silkstone Common, Yorkshire, UK
Posts: 5,719
silkstone is a glorious beacon of lightsilkstone is a glorious beacon of light
silkstone is a glorious beacon of lightsilkstone is a glorious beacon of lightsilkstone is a glorious beacon of lightsilkstone is a glorious beacon of lightsilkstone is a glorious beacon of lightsilkstone is a glorious beacon of lightsilkstone is a glorious beacon of lightsilkstone is a glorious beacon of lightsilkstone is a glorious beacon of lightsilkstone is a glorious beacon of lightsilkstone is a glorious beacon of light

Image editing O.K.
User's Gallery
Users Camera Equipment List
Re: What does "Stops" mean in Photography ?

That's where the histogram is your best friend.

If you review the shot with the histogram displayed, any spikes up the left or right hand sides mean that the shadows or highlights are lost to pure black or pure white.

In those cases there are several options...

Use a graduated filter to reduce the brightness of the sky.
Use fill-in flash to lighten the foreground.
Take several shots - exposed for the lightest and darkest tones - and combine them (HDR).
Exclude the brightest parts (e.g. light grey sky) from the scene altogether.
Decide that some loss of detail doesn't matter, so expose for the main subject.
silkstone is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote
Old 21-09-2007, 12:16   #5 (permalink)
Quite Chatty
 
Join Date: Sep 2007
Location: Lordswood, Kent
Posts: 86
ise438 is on a distinguished roadise438 is on a distinguished road

Image editing O.K.
User's Gallery
Users Camera Equipment List
Re: What does "Stops" mean in Photography ?

Excellent thanks alot...
ise438 is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote
Old 21-09-2007, 12:32   #6 (permalink)
Forum Regular
 
Join Date: Jan 2007
Location: I conduct workshops in Andalucia, Spain
Posts: 782
Les Meehan is a jewel in the rough
Les Meehan is a jewel in the roughLes Meehan is a jewel in the roughLes Meehan is a jewel in the roughLes Meehan is a jewel in the roughLes Meehan is a jewel in the roughLes Meehan is a jewel in the roughLes Meehan is a jewel in the rough

Image editing O.K.
User's Gallery
Users Camera Equipment List
Re: What does "Stops" mean in Photography ?

Quote:
Originally Posted by ise438 View Post
Excellent reply...thanks..

So how can you tell if a shot is going to have more the 5EV ?

If there a technique that can be used or if it just down to experience ?
Check out my tutorial 'Creative Exposure Control' in the Articles and Tutorials section of this forum.

Les
Les Meehan is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote
Old 21-09-2007, 12:45   #7 (permalink)
Jolly nice person
 
Join Date: Aug 2006
Location: Wimbledon
Posts: 7,021
Angela is a jewel in the rough
Angela is a jewel in the roughAngela is a jewel in the roughAngela is a jewel in the roughAngela is a jewel in the roughAngela is a jewel in the roughAngela is a jewel in the roughAngela is a jewel in the rough

Image editing O.K.
User's Gallery
Users Camera Equipment List
Re: What does "Stops" mean in Photography ?

Quote:
Originally Posted by Les Meehan View Post
Check out my tutorial 'Creative Exposure Control' in the Articles and Tutorials section of this forum.

Les
Les's tutorial is here
Angela is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote
Old 21-09-2007, 13:39   #8 (permalink)
Forum Regular
 
Join Date: Jan 2007
Location: I conduct workshops in Andalucia, Spain
Posts: 782
Les Meehan is a jewel in the rough
Les Meehan is a jewel in the roughLes Meehan is a jewel in the roughLes Meehan is a jewel in the roughLes Meehan is a jewel in the roughLes Meehan is a jewel in the roughLes Meehan is a jewel in the roughLes Meehan is a jewel in the rough

Image editing O.K.
User's Gallery
Users Camera Equipment List
Re: What does "Stops" mean in Photography ?

Thanks Angela. didn't occur to me to put a link

Les
Les Meehan is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote
Old 21-09-2007, 15:24   #9 (permalink)
Forum Regular
 
Soupdragon's Avatar
 
Join Date: Oct 2006
Posts: 1,169
Soupdragon will become famous soon enoughSoupdragon will become famous soon enoughSoupdragon will become famous soon enoughSoupdragon will become famous soon enoughSoupdragon will become famous soon enoughSoupdragon will become famous soon enoughSoupdragon will become famous soon enoughSoupdragon will become famous soon enough

Image editing O.K.
User's Gallery
Re: What does "Stops" mean in Photography ?

Quote:
Originally Posted by silkstone View Post
A 'stop' is an increment of aperture or exposure. With aperture it goes....

f/1.4, f/1.8. f/2.8, f/4, f/5.6, f/8, f/11, f/16, f/22, etc.

f/1.4 is the largest aperture - f/22 is the smallest.

Each increment lets half as much light into the camera, so opening the aperture (which means reducing the f/number) by one stop has the same effect as halving the shutter speed.

It's probably more correct to talk in terms of 'Exposure Value' (EV) which has the same general meaning but can be applied to both shutter speed and aperture. i.e. 1EV means an increase or decrease of one stop (increment) of aperture, or doubling or halving the shutter speed.

In the case you mention, he means that the difference between the lightest and darkest parts of the image was 8EV (or 8 stops) - that's the 'dynamic range' of the scene. He says that the camera's sensor can only handle 5EV - any more than this and the shadows become black with no detail, or the highlights are 'blown' to white, again with no details.

The technique he is using to overcome this is called 'High Dynamic Range' (HDR) photography where you take several shots and different exposures and combine them by taking the shadow detail from one shot and the highlight detail from another - so you are compressing the dynamic range of the scene into something that can be reproduced as a photograph. There is software designed specifically to help you do this, such as Photomatix, but you can also do it on many image editors.

HTH!
Are stops inversely proportional to go's?
Soupdragon is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote
Old 21-09-2007, 15:32   #10 (permalink)
Jolly nice person
 
Join Date: Aug 2006
Location: Wimbledon
Posts: 7,021
Angela is a jewel in the rough
Angela is a jewel in the roughAngela is a jewel in the roughAngela is a jewel in the roughAngela is a jewel in the roughAngela is a jewel in the roughAngela is a jewel in the roughAngela is a jewel in the rough

Image editing O.K.
User's Gallery
Users Camera Equipment List
Re: What does "Stops" mean in Photography ?

Quote:
Originally Posted by silkstone View Post
f/1.4 is the largest aperture - f/22 is the smallest.

[snip]..so opening the aperture (which means reducing the f/number)
Whoever invented this backwards system needs flippin' shooting!
Angela is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote
Old 21-09-2007, 15:49   #11 (permalink)
Loves the place
 
silkstone's Avatar
 
Join Date: Jan 2005
Location: Silkstone Common, Yorkshire, UK
Posts: 5,719
silkstone is a glorious beacon of lightsilkstone is a glorious beacon of light
silkstone is a glorious beacon of lightsilkstone is a glorious beacon of lightsilkstone is a glorious beacon of lightsilkstone is a glorious beacon of lightsilkstone is a glorious beacon of lightsilkstone is a glorious beacon of lightsilkstone is a glorious beacon of lightsilkstone is a glorious beacon of lightsilkstone is a glorious beacon of lightsilkstone is a glorious beacon of lightsilkstone is a glorious beacon of light

Image editing O.K.
User's Gallery
Users Camera Equipment List
Re: What does "Stops" mean in Photography ?

Ah, well, it's because the f-number is the ratio of iris diameter (aperture) to focal length.

So f/4 on a 400mm lens means that the iris diameter is 400/4 = 100mm. That's why wide-aperture telephotos are so large and expensive! Being pedantic, it's also why it should strictly be written f/4 (or whatever) because the dividing f (focal length) by the number gives the diameter.

silkstone is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote
Old 21-09-2007, 16:14   #12 (permalink)
Ali
Feet under the table
 
Ali's Avatar
 
Join Date: May 2007
Location: Cornwall
Posts: 1,567
Ali will become famous soon enoughAli will become famous soon enoughAli will become famous soon enoughAli will become famous soon enoughAli will become famous soon enoughAli will become famous soon enoughAli will become famous soon enough

Image editing O.K.
User's Gallery
Users Camera Equipment List
Re: What does "Stops" mean in Photography ?

When I first started to attempt to get my head round apertures, exposure and the like.... I'd get myself in knots.

I am a girl who likes to keep things simple, the more simple the explanation the more likely it is I'll understand. Once I have a basic understanding I can usually start to grasp the more complex elements - but without a basic 'Ali Speak' explanation my head will go "la la la la" and I'll never get it.

I have the following written down in a little book that I make photography notes in... it's not techincal and probably not accurate but it helped me immensely. It might not make sense to any of you, but it makes perfect sense to me

Little number (F number) eg. F2.8 (opening up)
= big hole (aperture)
= less in focus (small/narrow depth of field - DOF)
= faster shutter speed (high number)

Big number (F number) eg. F16 (closing down/stopping down)
= small hole (aperture)
= more in focus (large/wider depth of field - DOF)
= slower shutter speed (lower number)
BUT... slow shutter speeds can make things blurry - camera shake as the shutter stays open for longer.

Combination of aperture and shutter speed determine amount of light = exposure.


Obviously it doesn't touch on the actual mathematical element of the F numbers and what is half of what and so on - I really struggle with numbers so the techincal explainations usually leave me reeling. This little note gave me a (very) basic grasp to build from.

You will often find me mumbling "big hole, little number, more fuzziness" in times of uncertainty (photography wise, obviously not while debating whether to buy a new car or not
Ali is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote
Old 21-09-2007, 16:40   #13 (permalink)
Forum Regular
 
Soupdragon's Avatar
 
Join Date: Oct 2006
Posts: 1,169
Soupdragon will become famous soon enoughSoupdragon will become famous soon enoughSoupdragon will become famous soon enoughSoupdragon will become famous soon enoughSoupdragon will become famous soon enoughSoupdragon will become famous soon enoughSoupdragon will become famous soon enoughSoupdragon will become famous soon enough

Image editing O.K.
User's Gallery
Re: What does "Stops" mean in Photography ?

I did write an article on this some time back.

If I could find it? I would post a link.
Soupdragon is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
"Color Boost - Photography Video Tutorial" j sotelo Tutorials and Guides 2 22-05-2007 13:29
Event Photography workshop "Techniques for Profit" - tickets available Pixalo News 0 02-02-2007 16:50
WARNING - Resizing Image in "one go" decreases PQ vs "staged" approach Dave Photo Manipulation 6 12-10-2005 12:52
The photography competition - "Summer" -closing date 07 Aug Steve News 9 15-08-2005 16:15


All times are GMT +1. The time now is 15:51.


vBulletin Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.
ReviewPost & PhotoPost vB3 Enhanced, Copyright 2003-2014 All Enthusiast, Inc.
SEO by vBSEO 3.3.0
Copyright 2006 - 2017 Pixalo.com

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196