Exposure Compensation


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blazer_workz

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#1
The camera system works by allowing a correct amount of light to hit on the film/sensor in order to correctly expose it. And to get this correct amount of light, we have 3 parameters to play with; aperture, shutter speed, and ISO.

We all know that this 3 parameters comes in measurement of stops.
ISO: 25, 50, 100, 200, 400, 800, 1600, ...
Aperture: 2, 2.8, 4, 5.6, 8, 11, 16, 22, ...
Shutter speed: 1/2000, 1/1000, 1/500, 1/250, 1/125, 1/60, 1/30, 1/15, 1/8, 1/4, ...

How about exposure compensation? How does it affect the camera system?

Exposure compensation usually comes like this.
EV: +3, +2, +1, 0, -1, -2, -3

How many stop is each step of exposure compensation?
How does exposure compensation works?
 

ExplorerZ

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#2
blazer_workz said:
The camera system works by allowing a correct amount of light to hit on the film/sensor in order to correctly expose it. And to get this correct amount of light, we have 3 parameters to play with; aperture, shutter speed, and ISO.

We all know that this 3 parameters comes in measurement of stops.
ISO: 25, 50, 100, 200, 400, 800, 1600, ...
Aperture: 2, 2.8, 4, 5.6, 8, 11, 16, 22, ...
Shutter speed: 1/2000, 1/1000, 1/500, 1/250, 1/125, 1/60, 1/30, 1/15, 1/8, 1/4, ...

How about exposure compensation? How does it affect the camera system?

Exposure compensation usually comes like this.
EV: +3, +2, +1, 0, -1, -2, -3

How many stop is each step of exposure compensation?
How does exposure compensation works?
EV compensation doesn't come as a stop they usually comes as -0.3, -0.7, -1, +0.3, +0.7, +1
+1 = a full stop which is from f4 > f2.8
if ur ev compensation is 0, you get a aperture of f4, when you increase it to +0.7, ur aperture should also increase by 2/3 stop which is f3.2 or f3.3 for most camera
 

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Phildate

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#4
It depends if you are shooting in Aperture-Priortity or Shutter-Priority mode. If I am in "A or Av" then applying EV will result in a change to the shutter speed. If I am in "S or Tv" then applying EV will result in a change in aperture.
 

blazer_workz

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#5
ExplorerZ said:
EV compensation doesn't come as a stop they usually comes as -0.3, -0.7, -1, +0.3, +0.7, +1
+1 = a full stop which is from f4 > f2.8
if ur ev compensation is 0, you get a aperture of f4, when you increase it to +0.7, ur aperture should also increase by 2/3 stop which is f3.2 or f3.3 for most camera
Thank you ExplorerZ.

If we are to say that exposure compensation is to adjust the value in a third stops (1/3 stops)..doesn't it make sense to adjust the aperture/shutter speed/ISO instead..as most of the DSLR comes with 1/3 stops adjustments..

E.g. At f/5.6, 1/125 for a EV compensation of -0.7
We can set to f/7.1, 1/125 or f/5.6, 1/200...Is this equivalent to a -0.7EV compensation?

But then, how about manual/film SLR? The older version of cameras are all mechanically controlled, and film speed depends on what you have loaded..hence the setting available are rather fixed..but it still does offer exposure compensation..How does it work for manual/film SLR then?
 

blazer_workz

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#6
ortega said:
it takes the correct exposure and adjusts it up or down (depends on the setting and amount)
Phildate said:
It depends if you are shooting in Aperture-Priortity or Shutter-Priority mode. If I am in "A or Av" then applying EV will result in a change to the shutter speed. If I am in "S or Tv" then applying EV will result in a change in aperture.
So does it means exposure compensation is not necessary for manual mode? Since with current modern DSLR we can achieve aperture/shutter speed/ISO all in a third stop.
 

sk.images

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#7
blazer_workz said:
Thank you ExplorerZ.

If we are to say that exposure compensation is to adjust the value in a third stops (1/3 stops)..doesn't it make sense to adjust the aperture/shutter speed/ISO instead..as most of the DSLR comes with 1/3 stops adjustments..

E.g. At f/5.6, 1/125 for a EV compensation of -0.7
We can set to f/7.1, 1/125 or f/5.6, 1/200...Is this equivalent to a -0.7EV compensation?

But then, how about manual/film SLR? The older version of cameras are all mechanically controlled, and film speed depends on what you have loaded..hence the setting available are rather fixed..but it still does offer exposure compensation..How does it work for manual/film SLR then?
You could do this but then you're using fully manual and no longer relying on TTL metering. You would only normally do this when both aperture and shutter speed are important to the picture you're trying to capture. Exposure compensation is usually used in difficult, but predictable circumstances, e.g. backlight, very bright scene (e.g. snow or sand) or dark scene/subject or when yuo want to achieve a certain look, even under controlled lighting, e.g. high keu in studio.
 

ExplorerZ

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#8
blazer_workz said:
So does it means exposure compensation is not necessary for manual mode? Since with current modern DSLR we can achieve aperture/shutter speed/ISO all in a third stop.
some camera including dSLR only can choose ISO in a full stop, like 200 > 400 straight. and most of the time EV compensation doesn't change the ISO value, it only tweak with the shutter and aperture.

Thank you ExplorerZ.

If we are to say that exposure compensation is to adjust the value in a third stops (1/3 stops)..doesn't it make sense to adjust the aperture/shutter speed/ISO instead..as most of the DSLR comes with 1/3 stops adjustments..

E.g. At f/5.6, 1/125 for a EV compensation of -0.7
We can set to f/7.1, 1/125 or f/5.6, 1/200...Is this equivalent to a -0.7EV compensation?


But then, how about manual/film SLR? The older version of cameras are all mechanically controlled, and film speed depends on what you have loaded..hence the setting available are rather fixed..but it still does offer exposure compensation..How does it work for manual/film SLR then?
if at f5.6, 1/125 and f7.1, 1/125 is not equivalent. f7.1, 1/125 will give you -1.3EV since the aperture is 2/3stop slower than at f5.6. the same goes for f5.6, 1/200. (1/200 is 2/3stop faster which in terms give you lesser exposure)
 

ortega

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#9
blazer_workz said:
So does it means exposure compensation is not necessary for manual mode? Since with current modern DSLR we can achieve aperture/shutter speed/ISO all in a third stop.
why do you need to use manual mode?

1. look at your intended image
2. DOF important? use Aperture-Priortity mode
3. Freeze motion or motion blur? use Shutter-Priority mode
4. Meter and look at the exposure that the camera meter sets
5. press the shutter button
6. too bright? use exposure compensation set to - EV
7. too dark? use exposure compensation set to + EV

the beauty of a preview LCD
 

kietgnoel

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#10
Exposure compensation works the same way for both digital and film cameras. When setting exposure compensation, only the aperture and shutter speeds (either one or both) are affected. ISO is not.

Let's say that with zero exposure compensation (i.e. NO compensation), the camera meters and picks 1/250 for shutter speed and f/5.6 for aperture as the correct exposure for a given scene. You then set an exposure compensation of +1. This means that you want the camera to expose more (i.e. allow more light in) by 1 stop.

If you are using aperture priority mode (Av), then the shutter speed is automatically changed to 1/125 = 1 stop more light.

If you are using shutter priority mode (Tv), then the aperture is automatically changed to f/4 = 1 stop more light.

If you are using program mode (P), then either the shutter speed or aperture or both are adjusted accordingly, depending on how the camera was programmed to behave for that scene. E.g. shutter speed might be changed to 1/200 while the aperture is changed to f/4.5 - this still gives you 1 stop more light.
 

blazer_workz

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#11
cyber_m0nkey said:
You could do this but then you're using fully manual and no longer relying on TTL metering. You would only normally do this when both aperture and shutter speed are important to the picture you're trying to capture. Exposure compensation is usually used in difficult, but predictable circumstances, e.g. backlight, very bright scene (e.g. snow or sand) or dark scene/subject or when yuo want to achieve a certain look, even under controlled lighting, e.g. high keu in studio.
Thank you cyber_m0nkey.

From what you have explained. I kind of agree with you.
Yes, exposure compensation is for tricky lighting example bright foreground (-EV) or dark foreground (+EV). But how does it work to affect the light by a third stop?
 

ExplorerZ

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#12
blazer_workz said:
Thank you cyber_m0nkey.

From what you have explained. I kind of agree with you.
Yes, exposure compensation is for tricky lighting example bright foreground (-EV) or dark foreground (+EV). But how does it work to affect the light by a third stop?
1/3 and 2/3 is a faction of a full stop. sometimes when you don need to increase/decrease that much of exposure 1/3 or 2/3 will be better choice than a full stop.
 

blazer_workz

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#13
ExplorerZ said:
some camera including dSLR only can choose ISO in a full stop, like 200 > 400 straight. and most of the time EV compensation doesn't change the ISO value, it only tweak with the shutter and aperture.
So does it mean for manual mode when I do exposure compensation the settings that I use will be change..meaning the aperture or shutter speed that I've set will be tweak?

ExplorerZ said:
if at f5.6, 1/125 and f7.1, 1/125 is not equivalent. f7.1, 1/125 will give you -1.3EV since the aperture is 2/3stop slower than at f5.6. the same goes for f5.6, 1/200. (1/200 is 2/3stop faster which in terms give you lesser exposure)
I don't get you here.

Isn't f/5.6 -> f/7.1 (-2/3 stop) and 1/125 -> 1/200 (-2/3 stop)
Or -2/3 stop not equal to -0.7EV
 

blazer_workz

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#14
ExplorerZ said:
1/3 and 2/3 is a faction of a full stop. sometimes when you don need to increase/decrease that much of exposure 1/3 or 2/3 will be better choice than a full stop.
Yes agree. But with current technology..aperture and shutter speed settings and even ISO settings comes in a third stop..so is it still necessary for exposure compensation?
 

blazer_workz

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#15
ortega said:
why do you need to use manual mode?

1. look at your intended image
2. DOF important? use Aperture-Priortity mode
3. Freeze motion or motion blur? use Shutter-Priority mode
4. Meter and look at the exposure that the camera meter sets
5. press the shutter button
6. too bright? use exposure compensation set to - EV
7. too dark? use exposure compensation set to + EV

the beauty of a preview LCD
Agree. But can I say that with the setting that I got using aperture or shutter priority mode, I can use manual mode to tweak it +/-EV, using shutter speed for Av mode, and using aperture for Tv mode..So I can also says that exposure compensation is not necessary for manual mode?
 

ExplorerZ

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#16
blazer_workz said:
Yes agree. But with current technology..aperture and shutter speed settings and even ISO settings comes in a third stop..so is it still necessary for exposure compensation?
ok from this statement, i can tell that you got no or very low understanding of exposure compensation.
exposure compensation is only needed when the lighting is tricky such as backlighting where the foreground is underexposed. exposure compensation of +0.7 will helps to lit up the background by taking 0.7 stops more of light.

exposure compensation is still needed for manual, just that the way of input is different. in shutter/apreture mode you can input by a third stop and the camera will automatically set aperture/shutter according. where as in manual you will be be the one choosing if the increase should be on setting higher/lower aperture or shutter.
 

blazer_workz

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#17
kietgnoel said:
Exposure compensation works the same way for both digital and film cameras. When setting exposure compensation, only the aperture and shutter speeds (either one or both) are affected. ISO is not.

Let's say that with zero exposure compensation (i.e. NO compensation), the camera meters and picks 1/250 for shutter speed and f/5.6 for aperture as the correct exposure for a given scene. You then set an exposure compensation of +1. This means that you want the camera to expose more (i.e. allow more light in) by 1 stop.

If you are using aperture priority mode (Av), then the shutter speed is automatically changed to 1/125 = 1 stop more light.

If you are using shutter priority mode (Tv), then the aperture is automatically changed to f/4 = 1 stop more light.

If you are using program mode (P), then either the shutter speed or aperture or both are adjusted accordingly, depending on how the camera was programmed to behave for that scene. E.g. shutter speed might be changed to 1/200 while the aperture is changed to f/4.5 - this still gives you 1 stop more light.
Agree. But what about the exposure compensation available on those old manual cameras/manual lens?
Aperture/Shutter speed/ISO are all restricted.

Aperture is determined by the setting u fixed on the aperture ring.
Shutter speed is determined by the mechanical construction.
ISO is fixed by the film you load.

But it still offers exposure compensation of +3, +2, +1, 0, -1, -2, -3.

How is this possible?
 

ExplorerZ

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#18
blazer_workz said:
So does it mean for manual mode when I do exposure compensation the settings that I use will be change..meaning the aperture or shutter speed that I've set will be tweak?



I don't get you here.

Isn't f/5.6 -> f/7.1 (-2/3 stop) and 1/125 -> 1/200 (-2/3 stop)
Or -2/3 stop not equal to -0.7EV
yes for both the question.

f5.6 is 2/3 stop faster than f7.1 and 1/125 is slower than 1/200 (i use the word slower becos shutter is calculated on time, having a slower shutter = getting more light)
 

ExplorerZ

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#19
blazer_workz said:
Agree. But what about the exposure compensation available on those old manual cameras/manual lens?
Aperture/Shutter speed/ISO are all restricted.

Aperture is determined by the setting u fixed on the aperture ring.
Shutter speed is determined by the mechanical construction.
ISO is fixed by the film you load.

But it still offers exposure compensation of +3, +2, +1, 0, -1, -2, -3.

How is this possible?
if you taking about full manual its very much possible like modern cam, just that the photographer will need to use a light meter, for example if the correct exposure is f8 and 1/100 for a asa100 film, a +1 compensation will be either f5.6 and 1/100 or f8 and 1/50 both on the same film.
 

blazer_workz

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#20
:confused:
I still don't get it..kind of confused. I will re-phrase my questions.

Q1.) Is exposure compensation equivalent to tweaking the aperture or shutter speed in steps of a third stop depending on what you have set?
e.g. -0.7EV (-2/3 stop) exposure compensation:
In Av mode f/5.6,1/125 -> f/5.6,1/200
In Tv mode f/5.6,1/125 -> f/7.1,1/125
In P or M mode f/5.6,1/125 -> f5.6,1/200 or f/7.1,1/125 or f/6.3,1/160

Q2.) So if I shoot in manual mode: to get -0.7EV
I can just select the necessary combination to drop by -0.7EV and not needing to set the exposure compensation value?

Q3.) How does the old type of cameras achieve exposure compensation?
Aperture is fixed by aperture ring
Shutter speed is fixed mechanically
ISO is fixed by film loaded into it

:dunno:
 

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