Exposure compensation and Aperture/Shttuer settings


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LBL2009

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#1
What's the difference between using exposure compensation and aperture/shutter settings to achieve over exposed or under exposed picture?

I can change the aperture or shutter to make the picture over or under exposed in M mode, then when do I use the exposure compensation? Is it for fine tuning?

Or exposure compensation is mainly used in P, A and S mode since the camera sets the aperture/shutter combination for us?
 

luna_sea83

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#2
Exposure Compensation is mainly used in P,A and S mode
 

Numnumball

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#3
Remember our eyes see things in perpetual continuty like a video but camera captures collective light in oics over a variable duration. To the camera,it's jus a circle and its eventual tonal intensity is quite variably dependent on the proportion it and the overall exposure set will affect it. Any brighter in life can eventually ends up darker in the final pic if the shutrter duration is short OR bright if the shutter duration is long.

Thats where the Exposure compensation comes in where we need to tell the camera what to do by our manual judgement in which we deem to be too dark or bright..

Like wad Luna_sea says : Exposure Compensation is mainly used in P,A and S mode and it's adjustable after exposure calculate based on ur metering modes..

Hope the above helps

Cheers
 

ZerocoolAstra

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#4
What's the difference between using exposure compensation and aperture/shutter settings to achieve over exposed or under exposed picture?

I can change the aperture or shutter to make the picture over or under exposed in M mode, then when do I use the exposure compensation? Is it for fine tuning?

Or exposure compensation is mainly used in P, A and S mode since the camera sets the aperture/shutter combination for us?
If your camera is in Manual mode, you can try:

1) set the aperture and shutter speed to whatever you think is the appropriate setting. Fire a shot.

2) change the exposure compensation value, say, to +1EV. Fire a shot.

review on your PC. Do you see any difference?
that's your answer.

oh i forgot. to be scientific, of course you have to keep the other variables the same. So best to mount on tripod and focus on the same object.
 

Diavonex

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Sep 23, 2008
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#5
What's the difference between using exposure compensation and aperture/shutter settings to achieve over exposed or under exposed picture?

I can change the aperture or shutter to make the picture over or under exposed in M mode, then when do I use the exposure compensation? Is it for fine tuning?

Or exposure compensation is mainly used in P, A and S mode since the camera sets the aperture/shutter combination for us?
If you are using Automatic to: 1. shoot against the light 2. shoot a subject against a white/black background, you can use exposure compensation to correct the over/under exposure.
 

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Aug 1, 2009
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#6
If your camera is in Manual mode, you can try:

1) set the aperture and shutter speed to whatever you think is the appropriate setting. Fire a shot.

2) change the exposure compensation value, say, to +1EV. Fire a shot.

review on your PC. Do you see any difference?
that's your answer.

oh i forgot. to be scientific, of course you have to keep the other variables the same. So best to mount on tripod and focus on the same object.

Ah... Exposure compensation doesn't work in manual mode (i'm sure i think, i never use it in manual mode anyway can just adjust shutterspeed) It only moves ur Exposure bar left or right.

Exposure compensation is for quick use in A S or P mode when the CPU sets the shutter speed/aperture or both for you, but it's still too dark or light to your liking, (since it's based on metering and you want to keep that setting to shoot) just hit Exposure compensation then change it to how u want to change the shot taken.



Ok for example u r in A mode with F/2.8 which u want to take a photo with to create an effect with shallow DoF, CPU selects 1/500s for S speed based on matrix metering. But u took the shot and it's too bright. so u flip ur EC to -1.0 or w/e then shoot again.
If you switch to f/5.6 to reduce light, the CPU will sellect 1/1000s to match the metering. if u go manual, and u reduce to f/5.6 and set to 1/500s, you loose your shallow DoF. Remember to check your histograms etc and see that nothing is blown or too dark.

I hope it helped, and i'm not wrong. HAHA =X :eek:
 

night86mare

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#7
What's the difference between using exposure compensation and aperture/shutter settings to achieve over exposed or under exposed picture?

I can change the aperture or shutter to make the picture over or under exposed in M mode, then when do I use the exposure compensation? Is it for fine tuning?

Or exposure compensation is mainly used in P, A and S mode since the camera sets the aperture/shutter combination for us?
i think you mean, P,A,S mode versus M mode.

sometimes the metering is "fooled" , i.e. the scene is tricky and whatever the camera thinks is right based on whatever mode you have chosen for metering, that is wrong. other times, we deliberately want to override the "typically correct exposure", you can deliberatley overexpose or underexpose to great effect.

this is when exposure compensation will come in.

as for adjustment of shutter/aperture versus just EV adjustment.. that is just different ways to do the same thing.
 

Aug 1, 2009
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#8
Lets bring it up 1 level ok?


Lets say for Aperture Priority mode; I select f/1.4 and the cpu selects 1/1000 second.
This should by right produce the same image as M mode f/1.4 and 1/1000 correct?

But since EV doesn't work in M mode, if i dial EV - 3.0 in A mode, i can get a dark photo with shallow DoF compared to in M mode. To achieve the same effect in M mode, i've to make the shutter speed 1/1250. Am i correct to say this?

So what happens if the settings are at
A: f/1.4 1/4000
M: f/1.4 1/4000

If i hit EV -3.0 for A mode to make a darker photo,
i can't do the same in Manual mode to make a darker photo. Screwed?

So the bottom line, is EV a electronic change to the sensor or is it mechanical which adjusts the settings of the shot taken. So in Case 2, hitting EV won't help for A mode.
 

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catchlights

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#9
What's the difference between using exposure compensation and aperture/shutter settings to achieve over exposed or under exposed picture?

I can change the aperture or shutter to make the picture over or under exposed in M mode, then when do I use the exposure compensation? Is it for fine tuning?

Or exposure compensation is mainly used in P, A and S mode since the camera sets the aperture/shutter combination for us?
AFAIK, exposure compensation does work on Manual exposure mode.

exposure compensation is simply telling the camera meter to bias towards a one area where the photographer preferred, so when the camera is on P, A and S mode, the exposure compensation will alter the final exposure.

Where as on Manual exposure mode, exposure compensation is indicate the bias of exposure metering, photographer still have decide what is the exposure setting to use.
 

LBL2009

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#10
Thanks all.

After getting your inputs, I tried exposure compensation on P, S, A and M mode in the last two days and at night.

This is what I found -

1. Exposure compensation works in all four modes
2. It helps to achieve the result I want without changing the aperture/shutter combination set by the camera or by myself
3. It is most useful in low light situation when a correct exposure may require shutter speed to be set in seconds at widest aperture if flash is not used. Without a tripot, this will be a problem. However, by setting EV to +5 at widest aperture and iso 1600, I could still get a clear picture at 1/50 second at night under room lighting without flash and tripot.

This is the picture -

f3.5, 1/50, iso1600, EV+5, WB incandescent

 

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catchlights

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#11
Thanks all.

After getting your inputs, I tried exposure compensation on P, S, A and M mode in the last two days and at night.

This is what I found -

1. Exposure compensation works in all four modes
2. It helps to achieve the result I want without changing the aperture/shutter combination set by the camera or by myself
3. It is most useful in low light situation when a correct exposure may require shutter speed to be set in seconds at widest aperture if flash is not used. Without a tripot, this will be a problem. However, by setting EV to +5 at widest aperture and iso 1600, I could still get a clear picture at 1/50 second at night under room lighting without flash and tripot.

This is the picture -

f3.5, 1/50, iso1600, EV+5

not sure what are you try to achieve in your photo.

you use Exposure compensation is when you know the camera meter will not give you the correct setting, so you set Exposure compensation to override the camera meter.

for an example, if you put a person wearing white in front of a white wall, the camera meter will be fool and give underexposed image, and if you place a black cat in front of a black wall, the camera meter will be fool again and give you a overexposed images, this is when you need to override the camera meter by using Exposure compensation.
 

megaweb

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#12
What's the difference between using exposure compensation and aperture/shutter settings to achieve over exposed or under exposed picture?
Yes, there is a difference. Exposure compensation in auto mode (P, A and S modes) can achieve over exposed or under exposed picture. However aperture/shutter settings cannot achieve over exposed or under exposed picture.

I can change the aperture or shutter to make the picture over or under exposed in M mode, then when do I use the exposure compensation? Is it for fine tuning?
Exposure compensation works in auto mode only which is P, A or S mode, and not in manual mode.

Or exposure compensation is mainly used in P, A and S mode since the camera sets the aperture/shutter combination for us?
You are absolutely right.
 

LBL2009

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#13
not sure what are you try to achieve in your photo.

you use Exposure compensation is when you know the camera meter will not give you the correct setting, so you set Exposure compensation to override the camera meter.

for an example, if you put a person wearing white in front of a white wall, the camera meter will be fool and give underexposed image, and if you place a black cat in front of a black wall, the camera meter will be fool again and give you a overexposed images, this is when you need to override the camera meter by using Exposure compensation.
Thanks. I learn something from you.

I was trying to shoot a picture at low light situation without flash and to avoid very low shutter speed called by the camera meter. The picture shown is closer to the 'true' scene. With flash, the picture would be too bright and not showing the 'true' scene. At very low shutter speed without a tripot, my shaky hand gave me a blurred picture. This is a learning shot to see how EV can help me, in this case, a low light situation. Not sure this is the right way to use EV though.
 

catchlights

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#14
Yes, there is a difference. Exposure compensation in auto mode (P, A and S modes) can achieve over exposed or under exposed picture. However aperture/shutter settings cannot achieve over exposed or under exposed picture.


Exposure compensation works in auto mode only which is P, A or S mode, and not in manual mode.


You are absolutely right.
Hi megaweb, Nikon and Canon does thing a little bit differently in Exposure compensation, I share what I know about Nikon in post #9.
 

Diavonex

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#15
Thanks. I learn something from you.

I was trying to shoot a picture at low light situation without flash and to avoid very low shutter speed called by the camera meter. The picture shown is closer to the 'true' scene. With flash, the picture would be too bright and not showing the 'true' scene. At very low shutter speed without a tripot, my shaky hand gave me a blurred picture. This is a learning shot to see how EV can help me, in this case, a low light situation. Not sure this is the right way to use EV though.
You should be playing with your aperture and ISO instead of Exposure Compensation to allow for higher shutter speed.
 

Diavonex

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#16
Wider aperture will allow more light to reach sensor.

Higher ISO will increase sensitivity of sensor.

A combination of these two (i.e. aperture+ISO) will give you higher shutter speed thus avoiding the use of tripod and camera shake.
 

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Diavonex

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#17
EV (Exposure compensation) is generally used in tricky light situation e.g. back lighting or when you want to deliberately over or under-expose a picture when in auto.
 

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#19
This is a good thread.
It fully support/correct the thoughts that I have regarding this type of question!
Thanks guys :thumbsup:
 

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