clarification needed on exposure compensation


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HTCahHTC

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May 9, 2008
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#1
hi guys!
sorry about this question, but it's a term i can't seem to understand (or i might have).
exposure compensation, let's say, i'm shooting at...
f/4
1/125
... and i dial in a -1EV
doesn't that make my...
aperture f/5.6/shutter speed 1/160?
if thats the case, we can just adjust the aperture/shutter speed accordingly, dont we?
or am i missing something here?:dunno:
 

flipfreak

Senior Member
Nov 26, 2007
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www.rogerchua.com
#2
hi guys!
sorry about this question, but it's a term i can't seem to understand (or i might have).
exposure compensation, let's say, i'm shooting at...
f/4
1/125
... and i dial in a -1EV
doesn't that make my...
aperture f/5.6/shutter speed 1/160?
if thats the case, we can just adjust the aperture/shutter speed accordingly, dont we?
or am i missing something here?:dunno:
shld be either f/5.6 1/125 or f/4 1/250.

u can adjust either if u using manual mode. if u using av or tv, u can only do that right?
 

HTCahHTC

Senior Member
May 9, 2008
896
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#3
shld be either f/5.6 1/125 or f/4 1/250.

u can adjust either if u using manual mode. if u using av or tv, u can only do that right?
haha. i'm just giving a rough idea here. i want to know the main purpose of exposure compensation function, even though it underexposed/overexposed can be adjusted through aperture/shutter speed.
 

Deadpoet

Senior Member
Oct 18, 2004
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#4
haha. i'm just giving a rough idea here. i want to know the main purpose of exposure compensation function, even though it underexposed/overexposed can be adjusted through aperture/shutter speed.
*faint*

why don't you test it out with your camera?
 

luntut

Senior Member
Oct 19, 2007
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Punggol
#5
one thing i learnt about EV compensation in one of my previous shoots:

M mode, f/5.6, 1/125. 0EV.
=> too dark. i cannot increase f/ size cos i want it to be constant, cos i am using 70-300, shooting long range. i need to set at least 1/125 to freeze motion on stage. ISO cannot go higher cos noise will be increasingly unacceptable to me. so i boosted EV.

M mode, f/5.6, 1/125, +2EV
=> brighter, but still not acceptable. ambience light is too low for a decently exposed picture. but stage motion is still freezed in each shot.

M mode, f/5.6, 1/125, +5EV Max.
=> maxed out EV value. image became acceptably exposed. motion still freezed in each shot.

Hence, i can only say that when i increased EV, it doesnt seem to increase aperture size since its already at its biggest at 300mm, no way it dropped shutter speed cos motion is stil frozen. so maybe increased ISO speed? but i doubt so, cos images came out pretty noiseless. D80 noise becomes unacceptable beyond 800. i was already at 800.

2 cents of mine.
 

HTCahHTC

Senior Member
May 9, 2008
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#6
*faint*

why don't you test it out with your camera?
i'm sorry. i've already tested out, but came out with the conclusion above. hence, posting this question. :(

one thing i learnt about EV compensation in one of my previous shoots:

M mode, f/5.6, 1/125. 0EV.
=> too dark. i cannot increase f/ size cos i want it to be constant, cos i am using 70-300, shooting long range. i need to set at least 1/125 to freeze motion on stage. ISO cannot go higher cos noise will be increasingly unacceptable to me. so i boosted EV.

M mode, f/5.6, 1/125, +2EV
=> brighter, but still not acceptable. ambience light is too low for a decently exposed picture. but stage motion is still freezed in each shot.

M mode, f/5.6, 1/125, +5EV Max.
=> maxed out EV value. image became acceptably exposed. motion still freezed in each shot.

Hence, i can only say that when i increased EV, it doesnt seem to increase aperture size since its already at its biggest at 300mm, no way it dropped shutter speed cos motion is stil frozen. so maybe increased ISO speed? but i doubt so, cos images came out pretty noiseless. D80 noise becomes unacceptable beyond 800. i was already at 800.

2 cents of mine.
hey. thanks alot! now i get it. thanks thanks. :)
 

catchlights

Moderator
Staff member
Sep 27, 2004
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Punggol, Singapore
www.foto-u.com
#7
exposure compensation,
put in a simple term is you override what the camera meter suggested.
if it is on auto exposure mode, it does affect the exposure.

if it is on manual mode, it does affect the meter reading.
 

catchlights

Moderator
Staff member
Sep 27, 2004
21,903
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Punggol, Singapore
www.foto-u.com
#8
one thing i learnt about EV compensation in one of my previous shoots:

M mode, f/5.6, 1/125. 0EV.
=> too dark. i cannot increase f/ size cos i want it to be constant, cos i am using 70-300, shooting long range. i need to set at least 1/125 to freeze motion on stage. ISO cannot go higher cos noise will be increasingly unacceptable to me. so i boosted EV.

M mode, f/5.6, 1/125, +2EV
=> brighter, but still not acceptable. ambience light is too low for a decently exposed picture. but stage motion is still freezed in each shot.

M mode, f/5.6, 1/125, +5EV Max.
=> maxed out EV value. image became acceptably exposed. motion still freezed in each shot.

Hence, i can only say that when i increased EV, it doesnt seem to increase aperture size since its already at its biggest at 300mm, no way it dropped shutter speed cos motion is stil frozen. so maybe increased ISO speed? but i doubt so, cos images came out pretty noiseless. D80 noise becomes unacceptable beyond 800. i was already at 800.

2 cents of mine.
if you are shooting M mode, and the ISO, aperture and shutter are remain the same, how could you have three different exposures at the same situation??
 

HTCahHTC

Senior Member
May 9, 2008
896
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#9
exposure compensation,
put in a simple term is you override what the camera meter suggested.
if it is on auto exposure mode, it does affect the exposure.

if it is on manual mode, it does affect the meter reading.
hey! thanks alot!
but when i'm on Tv mode, and i compensate +1EV at settings f/5.6 1/125, the aperture changes itself to f/4 (or somewhere around there)?
 

Reportage

Senior Member
Nov 24, 2008
5,785
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#10
Its how the camera algorithm is programmed to calculate the ideal settings. dont like it? then go manual.
 

catchlights

Moderator
Staff member
Sep 27, 2004
21,903
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48
Punggol, Singapore
www.foto-u.com
#12
hey! thanks alot!
but when i'm on Tv mode, and i compensate +1EV at settings f/5.6 1/125, the aperture changes itself to f/4 (or somewhere around there)?
Canon term TV is Shutter priority, so the shutter speed remain constant, hence camera change the Aperture value to compensate the exposure.

if you switch to AV (Aperture priority), the camera will change the shutter speed to compensate the exposure.
 

HTCahHTC

Senior Member
May 9, 2008
896
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#13
okay. thanks so much for clarifying! appreciate it! :)
 

acpical

New Member
Jul 25, 2007
414
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#14
one thing i learnt about EV compensation in one of my previous shoots:

M mode, f/5.6, 1/125. 0EV.
=> too dark. i cannot increase f/ size cos i want it to be constant, cos i am using 70-300, shooting long range. i need to set at least 1/125 to freeze motion on stage. ISO cannot go higher cos noise will be increasingly unacceptable to me. so i boosted EV.

M mode, f/5.6, 1/125, +2EV
=> brighter, but still not acceptable. ambience light is too low for a decently exposed picture. but stage motion is still freezed in each shot.

M mode, f/5.6, 1/125, +5EV Max.
=> maxed out EV value. image became acceptably exposed. motion still freezed in each shot.

Hence, i can only say that when i increased EV, it doesnt seem to increase aperture size since its already at its biggest at 300mm, no way it dropped shutter speed cos motion is stil frozen. so maybe increased ISO speed? but i doubt so, cos images came out pretty noiseless. D80 noise becomes unacceptable beyond 800. i was already at 800.

2 cents of mine.
if you are shooting M mode, and the ISO, aperture and shutter are remain the same, how could you have three different exposures at the same situation??
Yes, something has got to give. If you increase the EV while keeping aperture and shutter speed constant, ISO must go up.

Setting the EV doesn't magically allow more/less light while aperture, shutter speed and ISO are constant. Just that if you set e.g +2EV, the exposure is increased by two stops but the camera still shows it to be metered correctly (the scale in the viewfinder).
 

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